Imidafenacin

イミダフェナシン

Cas 170105-16-5

C₂₀H₂₁N₃O, 319.408

APPROVED JAPAN 2015-07-29

イミダフェナシン
Imidafenacin

C₂₀H₂₁N₃O : 319.4
[170105-16-5]

Imidafenacin (INN) is a urinary antispasmodic of the anticholinergic class. It’s molecular weight is 319.40 g/mol

Kyorin and Ono have developed and launched imidafenacin, an oral M1 and M3 muscarinic receptor antagonist. Family members of the product case, WO9515951, expire in the US in 2019

Imidafenacin was approved by Pharmaceuticals Medical Devices Agency of Japan (PMDA) on Apr 18, 2007. It was marketed as Uritos^® by Kyorin, and marketed as Staybla^® by Ono.

Imidafenacin is a potent M1 and M3-subtype antagonist indicated for the treatment of urinary urgency, frequent urination and urgency urinary incontinence due to overactive bladder.

Uritos^® is available as tablet for oral use, containing 0.1 mg of free Imidafenacin. The recommended dose is 0.1 mg twice daily, and it can be increased to 0.2 mg twice daily, if the efficacy was not enough.

Uritos^® / Staybla^®

MOA：Muscarinic acetylcholine receptor antagonist

Indication：Urinary incontinence; Urinary urgency and frequency

PAPER

WO-2016142173

Imidafenacin, the compound of formula (I), is an antimuscarinic agent marketed in Japan under the brand name Uritos® used to treat overactive bladder, a disease defined by the presence of urinary urgency, usually accompanied by frequency and nocturia, with or without urge incontinence. Overactive bladder dysfunction has a considerable impact on patient quality of life, although it does not affect survival.

(I)

Synthesis of 4-(2-methyl-1 -imidazolyl)-2,2-diphenylbutanamide is first disclosed in Japanese patent JP3294961 B2 as shown in Scheme 1 . 4-bromo-2,2-diphenylbutanenitrile (II) is reacted with three equivalents of 2-methylimidazol, in dimethylformamide and in the presence of triethylamine as a base, to afford 4-(2-methyl-1 H-imidazol-1 -yl)-2,2-diphenylbutanenitrile, compound of formula (III), which is purified by column chromatography and, further, converted into its hydrochloride salt and recrystallized. Then, compound (III) is hydrolyzed with an excess of 70% sulfuric acid at 140-150 °C, followed by basification and recrystallization to provide imidafenacin (I), in an overall yield of only 25% (as calculated by data provided in docume

(III) (I)

Scheme 1

This route of document JP3294961 B2 implies several drawbacks. Firstly, purification of intermediate (III) is carried out by means of chromatographic methods, which are generally expensive, environmentally unfriendly and time consuming. Secondly, the hydrolysis of the nitrile group is carried out under strong acidic conditions and high temperature not convenient for industrial application.

Japanese document JP2003-201281 discloses a process for preparing imidafenacin as shown in Scheme 2. 4-bromo-2,2-diphenylbutanenitrile (II) is reacted, with five equivalents of 2-methylimidazol, which acts also as a base, in dimethylsufoxide to provide intermediate (III), which after an isolation step is further reacted with phosphoric acid in ethanol to provide the phosphate salt of 4-(2-methyl-1 H-imidazol-1-yl)-2,2-diphenylbutanenitrile. Hydrolysis with potassium hydroxide, followed by purification with a synthetic adsorbent provides imidafenacin (I) in a moderate overall yield

(II) (I)

Scheme 2

The use of a synthetic adsorbent is associated with problems with operativities and purification efficiencies from the viewpoint of industrial production, therefore, the process disclosed in document JP2003-201281 is not suitable for industrial application.

EP1845091 A1 discloses a process for preparing imidafenacin, according to previous document JP2003-201281 , however the purification step is carried out by either preparing the hydrochloride or the phosphate salt of imidafenacin followed by neutralization as shown in Scheme 3. Purified imidafenacin is provided in low yield, overall yield of about 31 % (as calculated by data provided in document EP1845091 A1 ). This process has several disadvantages. Firstly, EP1845091 A1 states that the penultimate intermediate, the 4-(2-methyl-1 H-imidazol-1 -yl)-2,2-diphenylbutanenitrile phosphate is hygroscopic, which implies handling problems. Secondly, the additional steps carried out for purification increases the cost of the final imidafenacin process and the pharmaceutical compositions containing it, which already resulted in expensive medications.

(II) (I)

HCI or

H3PO4

purified (I) HCI or Ή3ΡΟ4

Scheme 3

The intermediate phosphate salt of 4-(2-methyl-1 H-imidazol-1 -yl)-2,2-diphenylbutanenitrile obtained and used in prior art processes is a solid form having needle-shaped crystals, which are difficult to filtrate. Moreover, said needle-shaped crystals are very hygroscopic and unstable and transform over time to other solid forms. In addition, the water absorbed by this solid form described in the prior art may react with the intermediate to generate further impurities.

Therefore, there is still a need to develop an improved industrially feasible process for the manufacture of imidafenacin in good purity and good yield, involving the use of stable intermediates having also improved handling characteristics.

Example 1 :

Preparation of 4-(2-methyl-1 H-imidazol-1 -yl)-2,2-diphenylbutanenitrile phosphate in solid Form I

4-bromo-2,2-diphenylbutanenitrile (II, 1.000 Kg, 3.33 mol) and 2-methylimidazol (1 .368 Kg, 16.66 mol) were heated in DMSO (0.8 L) at 100-105 °C for 7 hours. The solution was then cooled to 20-25 °C and toluene (2 L) and water (4 L) were added and stirred for 30 minutes. After phase separation, the aqueous layer was extracted with toluene (1 L). Organic layers were combined and washed twice with water (2 x 1 L). Distillation of toluene provided 4-(2-methyl-1 H-imidazol-1-yl)-2,2-diphenylbutanenitrile as a brown oil (0.915 Kg), which was, then, dissolved in dry acetone (3 L) and water (0.1 L), heated to 40-45°C and seeded with 4-(2-methyl-1 H-imidazol-1 -yl)-2,2-diphenylbutanenitrile phosphate. A solution of orthophosphoric acid (0.391 Kg, 3.39 mol) in acetone (2 L) was then added dropwise, maintaining temperature at 40-45 °C. Once the addition was finished, the reaction mixture was maintained 1 hour at 40-45 °C, cooled to 20-25 °C and stirred for 1 hour. The solid was filtered, washed with acetone (1 L), suspended in 2-propanol (10 L), heated at 80 °C and 2 L of solvent were distilled. The obtained suspension was then seeded with 4-(2-methyl-1 H-imidazol-1 -yl)-2,2-diphenylbutanenitrile phosphate solid Form I and maintained at 80 °C for 5 hours. The suspension was cooled down to 20-25°C, filtered off, washed with 2-propanol (1 L) and, finally, dried (45 °C, 0.5 torr, 12 hours).

Yield: 0.967 Kg (73%)

HPLC: 99.5 %

KF: 0.2 %

Optical microscopy: plate-shaped crystal habit as substantially in accordance to Figure 2.

PSD: D90 of 105 m

PXRD: Crystalline solid form as substantially in accordance to Figure 3.

DSC (10 °C/min): Endothermic peak with onset at 177 °C (-1 18 J/g), as substantially in accordance to Figure 4.

TGA (10 °C/min): Decomposition starting at 180 °C.

DVS: No significant weight gain up to 90% of relative humidity. At this humidity, a total increase of only 0.45% in weight was observed.

SCXRD: Crystal structure substantially in accordance to Figure 5. There are not water or solvent molecules in the crystal structure.

PATENT

https://www.google.com/patents/CN103351344A?cl=en

Overactive Bladder (symptomatic overactive bladder, 0AB) is a common chronic lower urinary tract dysfunction. Its incidence, United States and Europe over 75 year-old male incidence up to 42%, slightly lower incidence of women 31%; the incidence of domestic in Beijing 50 years of age for men was 16.4% for women over the age of 18 mixed The overall incidence of urinary incontinence and urge incontinence was 40.4 percent, seriously affecting the physical and mental health of the patient, reduced quality of life. Common antimuscarinic drugs in vivo and in vivo M receptor in some or all of binding with different affinities to improve the symptoms of OAB, but will also cause many side effects, such as dry mouth, constipation, cognitive impairment , tachycardia, blurred vision and so on. Imidafenacin have diphenylbutanoic amide structure, is a new high anticholinergic drugs, which selectively acts on the M3 and Ml receptors, blocking the contraction of the detrusor choline, so detrusor relaxation, reduce side effects of drugs. Meanwhile imidafenacin inhibit smooth muscle of the bladder and inhibiting acetylcholine free dual role, and selectivity for the bladder stronger than the salivary glands.

imidafenacin is a new diphenylbutanoic amides from Japan Ono Pharmaceutical Co., Ltd. jointly developed with Kyorin Pharmaceutical anticholinergics, structure (I) as follows:

The goods listed in June 2007 in Japan under the trade name: STAYBLA, chemical name: 4- (2-methyl-1-imidazolyl) _2,2- diphenylbutyric amide.

At present the preparation imidafenacin few reports, can be summed up as the following ways:

China Patent CN10699098 reported to bromoethyl diphenyl acetonitrile and 2-methylimidazole as a raw material, at 150 ° C condition, after the reaction DMF / triethylamine system, sulfuric acid hydrolysis reuse imidafenacin. The reaction equation is as follows:

BACKGROUND OF THE INVENTION This two-step method was 24% overall yield is too low, and the second step of the reaction is difficult to control. And the reaction product was purified by column chromatography required to obtain a purified product, is not conducive to industrial production.

Chinese patent CN101362721A referred to as the hydrolysis conditions for the preparation of sulfuric acid and organic acid mixed use imidafenacin yield have mentioned the smell.

 Although this method increases the yield, but still more by-product of the reaction, the product is not easy purification.

 Japanese Patent No. JP2005 / 023216 proposes hydrolysis under alkaline environment, and the use of products and solutions of salts hydrochloride salt and then purified product.

This method improves the yield of the second step of the hydrolysis reaction and simplified purification methods. But the need to use this method to purify salt activated carbon, and filtration devices require more stringent; and a need to be re-crystallized salt solution salt after the operation, a total of four steps of unit operations. Process more cumbersome and more stringent requirements for equipment, it is not conducive to industrial scale production. In addition, the product is dried for a long time, still remaining after solvent treatment product obtained, the purity of the product is still low.

DETAILED DESCRIPTION

 The following typical examples are intended to illustrate the present invention, simple replacement of skill in the art of the present invention or improvement made in all part of the present invention within the protection of technical solutions.

Example 1

4- (2-methyl-1-imidazolyl) -2,2-diphenyl butanamide hydrobromide. The 16.5 g (52 mmol) 4- (2- methyl-1-imidazolyl) -2,2-diphenyl butyramide crude into 100 mL of isopropanol, stirring was added 8.0 mL hydrobromic acid and isopropyl alcohol mixed solution (volume ratio of 1: 1), the solid gradually dissolved, was nearly colorless and transparent liquid. After maintaining the reaction mixture was stirred for half an hour, the reaction mixture was added to 100 mL of ethyl acetate, stirred for I hour at room temperature, solid precipitated. Filtration, and the cake was rinsed with an appropriate amount of ethyl acetate. The solid was collected, 40 ° C drying oven and dried to constant weight to give 19.5 g white 4- (2-methyl-1-imidazolyl) -2,2-diphenyl butyramide hydrobromide, yield 98.9%. ?] \ 1 .228.4-229.00C0MS (m / z): 320 [M + 1] +. 1H-NMR (DMS0-1 / 6, 400 MHz) δ: 2.25 (3H, s), 2.73-2.74 (2H, m), 3.68-3.91 (2H, m), 6.81 (1H, s), 7.28-7.35 (I OH, m), 7.39 (1H, s), 7.49 (1H, d, /=2.4 Hz), 7.55 (1H, d, J = 2.2 Hz), 14.39 (1¾ br s).

Example 2

4- (2-methyl-1-imidazolyl) -2,2-diphenyl butyramide. -2,2-Diphenyl butyric acid amide acetate was dissolved in 900 mL of water to 19.5 g (0.051mmol) obtained in Example 1 4- (2-methyl-1-imidazolyl) embodiment. Extracted with 900mL diethyl ether solution, collecting the inorganic layer. Was added to an aqueous solution of 200 mL of ethanol, was added to the system with stirring in an aqueous solution of KOH 2mol / L, there is a solid precipitated. The reaction was stirred I h after filtration. Cake was washed with 40% ethanol solution rinse, rinsed with water several times. Collect the cake, put 40 ° C drying oven dried to constant weight to give 14.8 g white 4- (2-methyl-1-imidazolyl) -2,2-diphenyl methylbutanamide, yield 91.0% (total yield 90% two steps). Μ.p.192.3-193.00C (CN101076521A 191-193O). MS (m / z): 320 [M + l] +. 1H-NMR (DMSO-J6, 400MHz) δ: 2.11 (3Η, s), 2.69-2.73 (2H, m), 3.61-3.65 (2H, m), 6.75 (1H, d, J = L OMHz), 7.01 (1H, br s), 7.04 (1H, d, J = L 0 MHz), 7.34-7.49 (11H, m).

Example 3

4- (2-methyl-1-imidazolyl) -2,2-diphenyl butyramide. The 14.5 g (0.045mmol) obtained in Example 4- (2-methyl-1-imidazolyl) -2,2-diphenyl butanamide 2 was added 116 mL of ethyl acetate was slowly heated to reflux reflux for 30 min, cooled to room temperature for crystallization 5 h. Suction filtered, the filter cake was rinsed with a small amount of ethanol, collected cake was put 40 ° C drying oven and dried to constant weight to give 13.4 g white 4- (2-methyl-1-imidazolyl) -2,2- diphenyl methylbutanamide refined products, yield 92.4% (three-step total yield 83.1%). Mp192.5-193 (TC (CN101076521A 191_193 ° C) .MS (m / z):.. 320 [M + 1] + 1H-NMR (DMSO-J6, 400 MHz) δ

2.11 (3H, 7.01 (1H,

s), 2.69-2.73 (2H, br s), 7.04 (1H, d,

m), 3.61-3.65 (2H, m), 6.75 (1H, J = L 0 MHz), 7.34-7.49 (11H, m).

PATENT

CN103772286A.

imidafenacin (Imidafenacin) is a new diphenylbutanoic amides from Japan Ono Pharmaceutical Co., Ltd. jointly developed with Kyorin Pharmaceutical anticholinergic drugs, bladder is highly selective for the treatment of overactive bladder, in 2007 in June in Japan. Its chemical name is 4- (2-methyl -1H- imidazol-1-yl) -2,2-diphenyl butyramide chemical structure shown by the following formula I:

Reported in U.S. Patent No. US5932607 imidafenacin preparation method, the method is based on 4-bromo-2 ‘2 ~ phenyl butyronitrile, 2-methylimidazole, triethylamine as raw materials, with DMF as a solvent at 150 ° C reaction 30h, to give the intermediate 4- (2-methyl-imidazol-1-yl) -2,2-diphenyl-butyronitrile, 77% yield, then body 140 ~ 150 ° C with 70% sulfuric acid The resulting intermediate hydrolyzed to the amide, after completion of the reaction required excess soda and sulfuric acid, the reaction is as follows:

Which preclude the use of the dilute sulfuric acid hydrolysis, although succeeded in getting the product, but the yield is very low, only 32%, greatly increasing the production cost, mainly due to 70% sulfuric acid, the reaction is difficult to control amide phase, the product will continue to acid hydrolysis byproducts, resulting in decreased yield.

 European Patent No. EP1845091 reports imidafenacin Another preparation method, the method using potassium hydroxide and isopropyl alcohol 4- (2-methyl-imidazol-1-yl) diphenyl _2,2- Hydrolysis of nitrile to amide phosphates, and the crude product was converted to the hydrochloride or phosphate, and recrystallized to remove impurities and then basified imidafenacin obtained, which reaction is as follows:

This method uses a lot of bases, product purification is too much trouble, and the total yield of 45%.

 Chinese Patent Publication No. CN102746235 also disclosed imidafenacin preparation method of 4- (2-methyl-1-yl) -2,2-diphenyl phosphate or nitrile salt in methanol / ethanol, dimethyl sulfoxide, and the presence of a base, with hydrogen peroxide in 40 ~ 60 ° C under through improved Radziszewski the target compound, the reaction is as follows:

The method used in the hydrogen peroxide solution, but a solution of hydrogen peroxide has strong oxidizing, and has a certain corrosive, inhalation of the vapor or mist respiratory irritation strong, direct eye contact with the liquid may cause irreversible damage and even blindness, security It is not high on the human body and environmentally unfriendly. Alkaline environment, easily decomposed hydrogen peroxide, as the temperature increases, the decomposition reaction increased, and therefore reaction requires a large excess of hydrogen peroxide solution.

The method comprises the steps of: (1) 4-Bromo-2,2-diphenyl-butyronitrile is hydrolyzed to the amide under basic conditions; (2) The obtained 4-bromo-2,2-diphenylbutyric amide is reacted with 2-methylimidazole to give the desired product.

Example 1

2L reaction flask was added 400mL of dry tetrahydrofuran, under a nitrogen atmosphere was added 60% sodium hydride (82.8g, 2.06mol), stirred to obtain a gray turbid solution A. With 400mL dry tetrahydrofuran was sufficiently dissolved diphenyl acetonitrile (200g, 1.04mol), I, 2- dibromoethane (204.2g, 1.08mol), to give a colorless clear liquid B; 5 ~ 15 ° C, a solution of turbid solution B dropwise to solution A, 10 ~ 15 ° C the reaction was incubated 6h, TLC until the reaction was complete, to the reaction system a small amount of water was added dropwise until no bubbles. After addition of 800mL water, 400mL ethyl acetate and stirred, liquid separation, the organic layer was washed with water, saturated sodium chloride solution, respectively, and the organic layer was dried over anhydrous sodium sulfate, suction filtered, concentrated under reduced pressure to give a yellow liquid 310g.

[0018] The resulting yellow liquid with 800mL 90% ethanol and stirred to dissolve at 40 ° C, then cooling and crystallization, filtration, 45 ° C and concentrated under reduced pressure to give a white solid 232.8g, 75% yield.

Preparation of bromo-2,2-diphenyl 4_ butanamide: [0019] Example 2

3L reaction flask was added 4-bromo-2,2-diphenyl-butyronitrile (15 (^, 0.511101), 7501 ^ 6mol / L KOH solution, 750mL dimethylsulfoxide and heated to 100 ~ 120 ° C under stirring The reaction, the reaction lh, until the reaction was complete by TLC after cooling to 40 V, add 2000mL water, 2000mL of methylene chloride was stirred, liquid separation, the organic layer was washed with water, washed with saturated sodium bicarbonate and sodium chloride solution, separated, dried over anhydrous The organic layer was dried over sodium sulphate, filtration, concentrated under reduced pressure to give brown oily liquid 161.92g, 96% yield.

Preparation of bromo-2,2-diphenyl 4_ butanamide: [0020] Example 3

3L reaction flask was added 4-bromo-2,2-diphenyl-butyronitrile (150g, 0.5mol), 666mL 6mol / L NaOH solution, 750mL dimethylsulfoxide, the reaction mixture was stirred and heated to 100 ~ 120 ° C under The reaction lh, until the reaction was complete by TLC after cooling to 40 ° C, add water 2000mL, 2000mL of methylene chloride was stirred, liquid separation, the organic layer was washed with water, washed with saturated sodium bicarbonate and sodium chloride solution, separated, dried over anhydrous sulfate sodium organic layer was dried, filtration, concentrated under reduced pressure to give brown oily liquid 146.73g, 87% yield.

Preparation of bromo-2,2-diphenyl 4_ butanamide: [0021] Example 4

The reaction was stirred 3L reaction flask was added 4-bromo-2,2-diphenyl-butyronitrile (15 (^, 0.511101), 8331 ^ 36% Na2CO3 solution, 750mL dimethylsulfoxide and heated to 100 ~ 120 ° C under The reaction lh, until the reaction was complete by TLC after cooling to 40 ° C, add water 2000mL, 2000mL of methylene chloride was stirred, liquid separation, the organic layer was washed with water, washed with saturated sodium bicarbonate and sodium chloride solution, separated, dried over anhydrous The organic layer was dried over sodium sulphate, filtration, concentrated under reduced pressure to give brown oily liquid 153.48g, yield 91%.

`[0022] Example 5: 4- (2-methyl-imidazol _1_ -1H- yl) butyramide _2,2_ diphenyl (imidafenacin) Preparation 5L reaction flask was added 4-bromo-2 2-diphenyl butyric amide (160g, L 5mol), 2- methyl imidazole (123g,

1.5mol), triethylamine (50.6g, 0.5mol), potassium iodide (5g, 0.03mol), fully dissolved with 1000mL DMF solution was heated to 120 ° C at a reaction 5h, until completion of the reaction by TLC, heating was stopped, to be After cooling, water was added 3000mL system stirred 0.5h, filtration, washed with water until the filtrate is neutral, concentrated under reduced pressure and dried to give a brown solid 146.14g, a yield of 91%.

[0023] Example 6: 4- (2-methyl-imidazol _1_ -1H- yl) butyramide _2,2_ diphenyl (imidafenacin) Preparation 5L reaction flask was added 4-bromo-2, 2- diphenyl butyramide (160g, 0.5mol), 2- methyl imidazole (82.1g,

1.011101), triethylamine (50.68,0.5mol), potassium iodide (5g, 0.03mol), fully dissolved with 1000mL DMF solution was heated to 120 ° C at a reaction 5h, until completion of the reaction by TLC, heating was stopped, the system was cooled until After adding 3000mL water, stirring 0.5h, filtration, washed with water until the filtrate is neutral, concentrated under reduced pressure and dried to give a brown solid 120.45g, 80% yield.

[0024] Example 7: 4- (2-methyl-imidazol _1_ -1H- yl) butyramide _2,2_ diphenyl (imidafenacin) Preparation 5L reaction flask was added 4-bromo-2, 2- diphenyl butyramide (160g, 0.5mol), 2_ methylimidazole (164.2g,

2.011101), triethylamine (50.68,0.5mol), potassium iodide (5g, 0.03mol), fully dissolved with 1000mL DMF solution was heated to 120 ° C at a reaction 5h, until completion of the reaction by TLC, heating was stopped, the system was cooled until After adding water, stirring 3000mL

0.5h, suction filtered, washed with water until the filtrate was neutral, and concentrated under reduced pressure, and dried to give a brown solid 141.33g, yield 88%.

[0025] Example 8: 4- (2-methyl imidazole -1H- _1_ group) _2,2_ diphenylbutanoic amide (imidafenacin) refining up to 80g microphone said that new crude added 300mL of absolute ethanol, the system was warmed to reflux, refluxed

0.5h, after cooling the ethanol was distilled off to IOOmL about 500mL of ethyl acetate was added to precipitate a white solid, a small amount of ethyl acetate and wash the filter cake, 45 ° C and dried in vacuo to give 74.6g of white crystals, yield 93%.

CLIP

Alkylation of diphenylacetonitrile (I) with dibromoethane provided bromide (II). This was condensed with 2-methylimidazole (III) in the presence of Et3N in DMF to afford the substituted imidazole (IV). Finally, hydrolysis of the cyano group of (IV) with 70% sulfuric acid produced the target amide.

Treatment of acetonitrile derivative (I) with dibromoethane (II) in toluene in the presence of NaNH2 affords bromo compound (III), which is then condensed with imidazole derivative (IV) by means of Et3N in DMF to provide compound (V). Hydrolysis of the cyano group of (V) with aqueous H2SO4 yields amide derivative (VI), which is finally subjected to alkyl quaternization by reaction with bromobenzyl bromide (VI) in acetone to furnish the desired product.

Paper

Bioorganic & Medicinal Chemistry Letters 9 (1999) 3003-3008

PAPER

Bioorganic & Medicinal Chemistry 7 (1999) 1151±1161

 4-(2-methyl-1-imidazolyl)- 2,2-diphenylbutyramide (2.02 g, 24%) as a colorless needle:

mp 189.0±190.0 C (from ethyl acetate:ethanol);

High MS (EI+) m/z calcd for C20H21N3O 319.1685, found 319.1671;

1 H NMR (400 MHz, CDCl3) d 2.23 (3H, s), 2.69±2.74 (2H, m), 3.77±3.82 (2H, m), 5.33 (1H, s), 5.49 (1H, s), 6.73 (1H, s), 6.85 (1H, s), 7.31±7.42 (10H, m).

PATENT

CN103880751A.

imidafenacin chemical name 4- (2-methyl–1H–1-yl) -2,2-diphenyl methylbutanamide (I).

In Patent JP93-341467, JP94-319355 and literature Bioorganic & Medicinal ChemistryLetters, 1999, vol.9,3003 – 3008 reported in the chemical synthesis routes to diphenyl acetonitrile (4) as the starting material,

Condensation and hydrolysis reaction step to give imidafenacin (1).

The new method is simple, mild reaction conditions, easy to control, good high yield and purity of the product, do not pollute the environment, suitable for industrial production.

[0012] The first method from 2-methylimidazole and I, 2- dibromoethane under phase transfer catalyst is tetrabutylammonium bromide (TBAB) and inorganic base catalyzed generate 1- (2-bromoethyl) – methyl -1H- imidazole (5), and diphenyl acetonitrile (4) a phase transfer catalyst and an inorganic base catalyzed condensation of 4- (2-methyl–1H- imidazol-1-yl) -2,2 – diphenylbutyronitrile hydrochloride (2), and then hydrolyzed to imidafenacin (I)

CLIP

http://dmd.aspetjournals.org/content/35/9/1624/T3.expansion.html

FIG. 1.

Chemical structures of [¹⁴C]imidafenacin and postulated metabolites, and their fragment ions. ^*, ¹⁴C labeled position; broken line, precursor and product ions obtained by collision-induced dissociation in LC/MS/MS.

1. Kobayashi F, Yageta Y, Segawa M, Matsuzawa S: Effects of imidafenacin (KRP-197/ONO-8025), a new anti-cholinergic agent, on muscarinic acetylcholine receptors. High affinities for M3 and M1 receptor subtypes and selectivity for urinary bladder over salivary gland. Arzneimittelforschung. 2007;57(2):92-100. [PubMed:17396619 ]
2. Miyachi H, Kiyota H, Uchiki H, Segawa M: Synthesis and antimuscarinic activity of a series of 4-(1-Imidazolyl)-2,2-diphenylbutyramides: discovery of potent and subtype-selective antimuscarinic agents. Bioorg Med Chem. 1999 Jun;7(6):1151-61. [PubMed:10428387 ]

Reference

• Kobayashi F, Yageta Y, Segawa M, Matsuzawa S (2007). “Effects of imidafenacin (KRP-197/ONO-8025), a new anti-cholinergic agent, on muscarinic acetylcholine receptors. High affinities for M3 and M1 receptor subtypes and selectivity for urinary bladder over salivary gland”. Arzneimittelforschung. 57 (2): 92–100. doi:10.1055/s-0031-1296589. PMID 17396619.
• Miyachi H, Kiyota H, Uchiki H, Segawa M (June 1999). “Synthesis and antimuscarinic activity of a series of 4-(1-Imidazolyl)-2,2-diphenylbutyramides: discovery of potent and subtype-selective antimuscarinic agents”. Bioorg. Med. Chem. 7 (6): 1151–61.doi:10.1016/S0968-0896(99)00003-6. PMID 10428387.

Imidafenacin

Systematic (IUPAC) name
4-(2-methyl-1H-imidazol-1-yl)-2,2-diphenylbutanamide
Clinical data
Routes of administration	Oral
Legal status
Legal status	℞ (Prescription only)
Identifiers
CAS Number	170105-16-5
ATC code	none
PubChem	CID 6433090
ChemSpider	4938278
UNII	XJR8Y07LJO
ChEMBL	CHEMBL53366
Chemical data
Formula	C20H21N3O
Molar mass	319.40 g/mol
SMILES CC1=NC=CN1CCC(C2=CC=CC=C2)(C3=CC=CC=C3)C(=O)N

//////////イミダフェナシン , D06273, KRP-197, KRP 197, ONO-8025, ONO 8025, UNII:XJR8Y07LJO, Kyorin, Ono ,Imidafenacin, 170105-16-5, JAPAN 2015,  Uritos^® , Staybla^®

Ranolazine

雷诺嗪

• MF C₂₄H₃₃N₃O₄
• MW 427.536

Sponsor/Developer: Gilead

Mechanism of action: Late sodium current inhibitor

Indication (Phase): Type 2 diabetes (Phase III)

A Phase 3 Study of Ranolazine in Subjects With Type 2 Diabetes Who Are Not Well Controlled on Metformin Alone (currently recruiting participants as of August 2012, ClinicalTrials.gov Identifier: NCT01555164, see the link here)

Chemical Name of Ranolazine: (RS)-N-(2,6-dimethylphenyl)-2-[4-[2-hydroxy-3-(2-methoxyphenoxy)-propyl]piperazin-1-yl]acetamide

N-(2,6-dimethylphenyl)-2-[4-[2-hydroxy-3-(2-methoxyphenoxy)propyl]piperazin-1-yl]acetamide

QA-2943

Ranexa®

CLIP

Ranolazine, developed by CV Therapeutics whom Gilead Sciences bought in 2009, is also sold under the trade name Ranexa for the treatment of  chronic angina (chest pain).

Ranolazine, a partial fatty acid oxidation inhibitor available that is also a late sodium channel inhibitor as an oral extended-release tablet, has been developed and launched by Gilead Palo Alto (formerly CV Therapeutics; CVT), a wholly owned subsidiary of Gilead Sciences, under license from Roche Bioscience (formerly Syntex)

Ranolazine, sold under the trade name Ranexa by Gilead Sciences, is a drug to treat angina that was first approved in 2006.

Angina also known as Angina pectoris is indication for heart disease caused by lack of blood circulation to the heart. The most widespread reason for the angina is Atherosclerosis. In coronary heart disease patients, arteries become narrow and stiff when compared with the healthy heart arteries. These narrow and stiff arteries cause difficulties to reach oxygen rich blood for heart. About 17 million Americans are suffering with coronary heart diseases and about 9 millions are suffering with chronic angina. Ranolazine is the one of the medicament used to manage chronic angina, developed by Roche Bioscience (formerly Syntex) and marketed by CV Therapeutics. USFDA was approved Ranolazine 2 under brand name of Ranexa® in January 27, 2006. Subsequently European medical agency (EMEA) approved in July 09, 2008. Latter on it was approved in few other developing countries. Ranexa ® is available in market in the form of 500 mg and 1000 mg film coated tablet and the maximum daily dosage should be less than 2.0g. Over dosage of Ranexa ® lead to dizziness, nausea, and vomiting. Worldwide sales of Ranexa® by December 2011 is about 400 millions USD (~2000 crores) with the consumption of 1, 00, 678 kg. Major contribution is from USA i.e. about 300 millions USD. ……..CLICK

(5) (a) Kluge, A. F.; Clark, R. D.; Strosberg, A. M.; Pascal, J. G.; Whiting, R. United states patent, US 4,567,264, 1986. (b) Kluge, A. F.; Clark, R. D.; Strosberg, A. M.; Pascal, J. C.; Whiting, R. L. European patent, EP 0,126,449, 1987. (c) Kluge, A. F.; Clark, R. D.; Strosberg, A. M.; Pascal, J. C.; Whiting, R. Canadian patent, CA 1256874, 1987.

Amongst the various synthetic routes described for the preparation of Ranolazine, some of the key approaches are discussed here under. Kluge.F.A et al 5 have reported two synthetic approaches for preparation of Ranolazine 2 using commercially available 2-Methoxy phenol 25 and 2, 6-dimethyl aniline 20 as key starting materials. The first synthetic route commenced with the synthesis of methyl oxirane derivative 27. Key intermediate methyl oxirane derivative 27 was synthesized from 25 and epichlorohydrin 26 in presence of NaOH employing Williamson reaction conditions. Thus obtained 27 treated with piperazine 23 in ethanol to obtain hydroxyl piperazine derivative 33. Thereafter, reaction of hydroxyl piperazine derivative 33 with phenyl acetamide derivative 22 in dimethylformamide afforded dihydrochloride salt of ranolazine 2, which was treated with ammonia to furnish ranolazine 2(Scheme 3.1).

Second synthetic path way for the preparation of ranolazine involves the condensation of piperazinyl acetamide intermediate 24 and methyl oxirane 27 in mixture of methanol and toluene (Scheme 3.2).

Mingfieng.S et al reported7 similar approach for the synthesis of Ranolazine 2 utilizing hydroxy propyl halide intermediate 94 instead of methyl oxirane compound 27. The requisite hydroxy propyl halide intermediate 94 prepared by reacting 2-methoxy phenol 25 with 1, 3- dichloropropan-2-ol 93 in presence of NaOH and mixture of ethanol & water as shown in Scheme 3.3.

(7) Lisheng, W.; Xiaoyu, F.; Hong-yuan, Z. Journal of Guangxi University (Natural Science Edition), 2003, 28, 301-303.

Eva.C.A et al.6 discovered an alternative synthetic path way for preparation of Ranolazine. As depicted in Scheme 3.3 reaction of phenyl acetamide derivative 22 with diethanolamine in presence of triethylamine and subsequent chlorination using thionyl chloride furnishes dichloro compound 91. Condensation of dichloro compound 91 with amino isopropanol derivative 92 provided Ranolazine 2. Amino isopropanol derivative 92 is achieved by reaction of methyl oxirane compound 27 with ammonia.

(6) Agai-Csongor, E.; Gizur, T.; Haranyl, K.; Trischler, F.; DemeterSzabo, A.; Csehi, A.; Vajda, E.; Szab-Koml si, G. European patent, EP 483932 A1, 1992.

2 with 99.9% purity.

IR (KBr, cm–1): 3331 (Amine, NH), 3002 (Aromatic, =CH), 2955, 2936 and 2834 (Ali, CH), 1686 (Amide, C=O), 1592 and 1495 (Aromatic, C═C), 1254 and 1022 (Ether, C-O-C) & 1125 (C-N).

1H NMR (500 MHz, DMSO–d6): δH 9.1 (s, 1H, N-H), 6.8-7.1 (m, 6H, ArH), 4.8 (s, 1H, OH), 3.9 (s, 1H, CH), 3.8-3.9 (dd, 2H, J=6.5 Hz, 10.7 Hz, CH2), 3.8 (s, 3H, CH3), 3.1 (s, 2H, CH2), 2.4-2.6 (m, 10H, CH2) 2.1 (s, 6H, CH3).

13C NMR (500 MHz, DMSO–d6): 18.23, 39.16, 39.83, 39.50, 39.76, 39.87, 53.18, 53.31, 55.50, 61.13, 61.44, 66.63, 71.96, 112.37, 113.64, 120.74, 120.03, 126.32, 127.62, 134.97, 135.06, 148.36, 149.17, 167.97.

M/S (m/z): 428.4(M+ + H).

CHN analysis: Anal. Calcd for C24H33N3O4 (427.54): C 67.42, H 7.78, N 9.83.; Found: C 67.62 H 7.47, N 9.68.

Medical uses

Ranolazine is used to treat chronic angina.^[1] It may be used concomitantly with β blockers, nitrates, calcium channel blockers,antiplatelet therapy, lipid-lowering therapy, ACE inhibitors, and angiotensin receptor blockers.^[2]

Contraindications

Some contraindications for ranolazine are related to its metabolism and are described under Drug Interactions. Additionally, in clinical trials ranolazine slightly increased QT interval in some patients^[3] and the FDA label contains a warning for doctors to beware of this effect in their patients.^[2] The drug’s effect on the QT interval is increased in the setting of liver dysfunction; thus it is contraindicated in persons with mild to severe liver disease.^[4]

Side effects

The most common side effects are dizziness (11.8%) and constipation (10.9%).^[1] Other side effects include headache and nausea.^[3]

Biological Activity

Conversion of different model animals based on BSA (Value based on data from FDA Draft Guidelines)

References

[1] Undrovinas AI, et al. J Cardiovasc Electrophysiol,?006, 17 Suppl 1, S169-S177.

[2] Song Y, et al. J Cardiovasc Pharmacol,?004, 44(2), 192-199.3]

3 Baptista T, et al. Circulation,?996, 93(1), 135-142.

Drug interactions

Ranolazine is metabolized mainly by the CYP3A enzyme. It also inhibits another metabolizing enzyme, cytochrome CYP2D6.^[2] For this reason, the doses of ranolazine and drugs that interact with those enzymes need to be adjusted when they are used by the same patient.

Ranolazine should not be used with drugs like ketoconazole, clarithromycin, and nelfinavir that strongly inhibit CYP3A nor with drugs that activate CYP3A like rifampin and phenobarbital.^[2]

For drugs that are moderate CYP3A inhibitors like diltiazem, verapamil, erythromycin, the dose of ranolazine should be reduced.^[2]

Drugs that are metabolized by CYP2D6 like tricyclic antidepressants may need to be given at reduced doses when administered with ranolazine.^[2]

Mechanism of action

Ranolazine inhibits persistent or late inward sodium current (I_Na) in heart muscle^[5] in a variety of voltage-gated sodium channels.^[6] Inhibiting that current leads to reductions in elevated intracellular calcium levels. This in turn leads to reduced tension in the heart wall, leading to reduced oxygen requirements for the muscle.^[3] The QT prolongation effect of ranolazine on the surface electrocardiogram is the result of inhibition of I_Kr, which prolongs the ventricular action potential.^[2]

Legal status

Ranolazine was approved by the FDA in January 2006, for the treatment of patients with chronic angina as a second-line treatment in addition to other drugs.^[3] In 2007 the label was updated to make ranolazine a first-line treatment, alone or with other drugs.^[3] In April 2008 ranolazine was approved by the European EMEA for use in angina.^[7]

History

In 1996, CV Therapeutics licensed the North American and European rights to ranolazine from Syntex, a subsidiary of Roche, which had discovered the drug and had developed it through Phase II trials in angina.^[8] In 2006, CV Therapeutics acquired the remaining worldwide rights to ranolazine from Roche.^[9] In 2008 CV Therapeutics exclusively licensed rights for ranolazine in Europe and some other countries to Menarini.^[10] In 2009, Gilead acquired CV Therapeutics.^[11] In 2013 Gilead expanded the partnership with Menarini to include additional countries, including those in Asia.^[12]

Ranolazine (CAS NO.: 95635-55-5), with its systematic name of 1-Piperazineacetamide, N-(2,6-dimethylphenyl)-4-(2-hydroxy-3-(2-methoxyphenoxy)propyl)-, could be produced through many synthetic methods.

Following is one of the synthesis routes:
The acylation of 2,6-dimethylaniline (II) with chloroacetyl chloride in the presence of triethylamine in dichloromethane affords N-(2,6-dimethylphenyl) chloroacetamide (III), which is condensed with piperidine (IV) in refluxing ethanol to yield N-(2,6-dimethylphenyl)-2-piperazinoacetamide IV). At last, this compound is condensed with 3-(2-methoxyphenoxy)-12-epoxypropane (VI) in refluxing methanol toluene.

CLIP

A novel strategy of ‘all water chemistry’ is reported for a concise total synthesis of the novel class anti-anginal drug ranolazine in its racemic (RS) and enantiopure [(R) and (S)] forms. The reactions at the crucial stages of the synthesis are promoted by water and led to the development of new water-assisted chemistries for (i) catalyst/base-free N-acylation of amine with acyl anhydride, (ii) base-free N-acylation of amine with acyl chloride, (iii) catalyst/base-free one-pot tandem N-alkylation and N-Boc deprotection, and (iv) base-free selective mono-alkylation of diamine (e.g., piperazine). The distinct advantages in performing the reactions in water have been demonstrated by performing the respective reactions in organic solvents that led to inferior results and the beneficial effect of water is attributed to the synergistic electrophile and nucleophile dual activation role of water. The new ‘all water’ strategy offers two green processes for the total synthesis of ranolazine in two and three steps with 77 and 69% overall yields, respectively, and which are devoid of the formation of the impurities that are generally associated with the preparation of ranolazine following the reported processes.

Damodara Naidu Kommi

Prof. Asit K. Chakraborti

PATENT

https://www.google.com/patents/US20130090475

Ranolazine, chemically known as (±)-N-(2,6-dimethylplenyl)-4-[2-hydroxy-3-(2-methoxyphenoxy)propyl]-1-piperazineacetamide, is represented by the formula as given below.

Ranolazine, a novel agent used to treat angina pectoris type coronary heart disease, was developed by American CV Therapeutica Company (now known as Gilead Sciences Company). Ranolazine has firstly been appeared on the market in US in 2006 and could be used to treat myocardial infarction, congestive heart disease, angina and arhythmia etc. The mechanism of action of ranolazine is to inhibit partial fatty acid oxidation, which changes fatty acid oxidation to glucose oxidation in heart, and thereby reduces the cardiac oxygen consumption. Ranolazine is the only antianginal agent without changing heart rate or blood pressure.

The processses for the preparation of ranolazine, which could be roughly divided into two types as shown in FIG. 1 and FIG. 2, were disclosed in International Application Publication No. WO 2010/025370, WO 2010/023687, WO 2009/153651, WO 2008/139492, WO 2008/047388, WO 2006/008753, Chinese patent No. CN101560196, CN101544617, CN1915982, the United States patent No. US2008312247, the publication China Pharmacist, 2007, 10(12), 1176-1177, Chinese Journal of Medicinal Chemistry, 2003, 13(5), 283-285, and Chinese Journal of Pharmaceuticals, 2004, 35(11): 641-642.

The process described in FIG. 1 (method 1) involves reacting [(2,6-dimethylphenyl)-carbamylmethyl]-peperazine with 1-(2-methoxyphenoxy)-2,3-epoxypropane to obtain ranolazine, in which comprises the steps of:

a) condensing 2,6-xylidine with chloroacetyl chloride in the presence of base to get amide, which is further reacted with piperazine by a substitution reaction of N-monoalkylation to get N-(2,6-dimethylphenyl)-1-piperazineacetamide, and

b) condensing guaiacol with epoxy chloropropane to get 1-(2-methoxyphenoxy)-2,3-epoxypropane.

As the condensation is carried out in the alkaline environment, the epoxy ring becomes easy to open loop, and thus the products comprise mixtures of open-looped and looped form, thereby requiring rigorous separation conditions and being difficult to achieve the desired purity in the following reaction.

The process described in FIG. 2 (method 2) involves reacting 2-chloro-N-(2,6-dimethylphenyl)-acetamide with 1-(2-methoxyphenoxy)-3-(N-piperazine)-2-hydroxypropane to get ranolazine, in which comprises the steps of:

a) condensing 2,6-xylidine with chloroacetyl chloride in the presence of base to get 2-chloro-N-(2,6-dimethylphenyl)-acetamide, and

b) condensing guaiacol with epoxy chloropropane to get 1-(2-methoxyphenoxy)-2,3-epoxypropane, which is further reacted with piperazine to get 1-(2-methoxyphenoxy)-3-(N-piperazine)-2-hydroxypropane.

As the condensation is carried out in the alkaline environment, the epoxy ring becomes easy to open loop, and thus the products comprise mixtures of open-looped and looped form, thereby requiring rigorous separation conditions and being difficult to achieve the desired purity in the following reaction. The monosubstitution reaction of N-alkylation reacted with peperazine is further difficult to be controlled to produce the desired products.

Compared with method 2, method 1 could be easier to be industrialized as the quality of intermediates obtained by method 1 could be easier to be controlled and also the method 1 could be easier to be operated. But in the repeated experiments, it was found that it still had a lot of difficulties in realizing the industrialization by method 1 although it could be easier to be operated as there are mixtures including open-looped and looped products rather than single product produced when guaiacol (o-methoxyphenol) was reacted with epoxy chloropropane, so the operation of distillatory separation would still need very high temperature (above 250° C.) and very low vacuum degree (5 mm Hg) with the disadvantages of high energy consumption, high facilities investment and tedious operation. And in the following condensation reaction, there are a lot of products were produced during the reaction so as to make the quality of the products hard to be controlled.

Example 1Preparation of N-(2,6-dimethylphenyl)-1-piperazinylacetamide1.1: Preparation of 2-chloro-N-(2,6-dimethylphenyl)-acetamid

30.5 g (0.252 mol) of 2,6-xylidine, 100 ml of ethyl acetate, 26.5 g (0.25 mol) of sodium carbonate were successively added into a 250 ml of 3-neck flask and placed in an ice-water bath. 36.5 g (0.323 mol) of chloroacetyl chloride was dissolved in 50 ml of ethyl acetate and then the mixture was dropwise added into the 3-neck flask till completion. The ice-water bath was removed and the reaction was carried out for 3 h at the room temperature. The reaction product was slowly added 100 ml of water in an ice-water bath, stirred for 10 min and filtered. The filter cake as white needle solid was washed and dried under vacuum to get 46.3 g of 2-chloro-N-(2,6-dimethylphenyl)-acetamide having a yield of 93%

1.2: Preparation of N-(2,6-dimethylphenyl)-1-piperazinylacetamide

58.3 g (0.3 mol) of piperazine hexahydrate was dissolved in 230 ml of ethanol and 50.0 g (0.25 mol) of 2-chloro-N-(2,6-dimethylphenyl)-acetamide was subsquently added. The mixture was heated under reflux for 3 h till completion. The reaction product was cooled to room temperature and filtered. The filter was concentrated under reduced pressure and 80 ml of water was added. The mixture was extracted with dichloromethane and the organic layer was concentrated under vacuum at 60° C. to get 39.4 g of N-(2,6-dimethylphenyl)-1-piperazinylacetamide having a yield of 63%. ¹HNMR (CDCl₃): 2.23˜2.27,s, 6H, 2.67,s, 4H, 2.96˜2.98,t, 4H, 3.19˜3.21,s, 2H, 7.08˜7.26,m, 3H, 8.69,s, 1H.

Example 2Preparation of Ring-Opening Halide2.1: Preparation of 1-chloro-3-(2-methoxyphenoxy)-2-propylalcohol

26 g (0.65 mol) of sodium hydroxide, 150 ml of water, 150 ml of ethanol, 62 g (0.5 g) of guaiacol were successively added into a reaction flask and 103 g (0.8 mol) of 1,3-dichloro-2-propylalcohol was slowly dropwise added till completion. The mixture was heated up to 45° C. for 24 h. The reaction product was extracted three times with 150 ml of dichloromethane each and the organic layer was combined, dried with anhydrous magnesium chloride and distilled under reduced pressure. The fraction at 160° C. and a pressure of 2 kp was collected to get 73.6 g of faint yellow liquid having a yield of 68%. ¹HNMR (CDCl₃): 3.44˜3.46,d, 1H, 3.69-3.78,dd, 2H, 3.85,s, 3H, 4.11˜4.12,d, 2H; 4.18˜4.22 μm, 1H, 6.89˜7.00,m, 4H. The result confirmed that the yellow liquid was 1-chloro-3-(2-methoxyphenoxy)-2-propylalcohol.

2.2: Preparation of 1-bromo-3-(2-methoxyphenoxy)-2-propylalcohol

26 g (0.65 mol) of sodium hydroxide, 150 ml of water, 150 ml of ethanol, 62 g (0.5 g) of guaiacol were successively added into a reaction flask and 174.4 g (0.8 mol) of 1,3-dibromo-2-propylalcohol was slowly dropwise added till completion. The mixture was heated up to 45° C. for 10 h. The reaction product was extracted three times with 150 ml of dichloromethane each and the organic layer was combined, dried with anhydrous magnesium chloride and distilled under reduced pressure. The fraction at 160° C. and a pressure of 2 kp was collected to get 103 g of faint yellow liquid of 1-bromo-3-(2-methoxyphenoxy)-2-propylalcohol having a yield of 79%.

Example 3Preparation of Ranolazine3.1: 1-chloro-3-(2-methoxyphenoxy)-2-propylalcohol as a raw material

2.5 g (0.01 mol) of 1-chloro-3-(2-methoxyphenoxy)-2-propylalcohol, 3.1 g (0.012 mol) of N-(2,6-dimethylphenyl)-1-piperazinylacetamide, 4.1 g (0.03 mol) of potassium carbonate, 25 ml of methanol and 50 ml of toluene were successively added into a reaction flask and heated under reflux for 4.5 h till completion.

The fraction whose main ingredient was methanol was collected by atmospheric distillation at boiling point of 62-68° C. and then filtrated. The filtrate was washed with 3N HCl to get 50 ml of liquid having a pH of 1-2 and further treated with 50 ml of saturated sodium carbonate solution to adjust pH to 9-10. The product was extracted three times with 20 ml of dichloromethane each and the lower organic phase was combined. After the dichloromethane was removed by distillation under reduced pressure and rotary evaporation, the yellow viscous liquid was obtained and then further dissolved in about 10 ml of methonal. The tetrahydrofuran was then dropwise added under reflux till turbidity. The product was slowly crystallized with cooling and filtrated to get 3.42 g of white solid having a yield of 80.1% by vacuum drying at 40° C

¹HNMR (CDCl₃): 2.22,s, 6H, 2.60˜2.62,t, 4H, 2.75,s, 6H, 3.21,s, 2H, 3.45,s, 3H; 3.85,s, 3H, 4.02˜4.04,t, 2H, 4.16,s, 1H, 6.88˜6.90,t, 2H, 6.91˜6.96,m, 2H, 7.08˜7.1,m, 3H, 8.65,s, 1H. The result confirmed that the compound obtained is ranolazine. Purity by HPLC (area normalization method): 99.1%.

PATENT

https://www.google.com/patents/CN102875490A?cl=zh

Ranolazine piperazine derivatives, chemical name: (±) -1- [3- (2_ methoxyphenoxy) -2_-hydroxypropyl] -4- [N- (2, 6- dimethylphenyl) carbamoylmethyl] piperazine. Ranolazine is a novel antianginal drugs, which can provide metabolic myocardial protection at the cellular level by improving myocardial energy, while heart rate, blood pressure and hemodynamic impact, has a good prospect. [0004] Currently, the literature synthetic routes ranolazine can be grouped into three: a route: literature (Wolff HeartFailure Reviews, 2002,7 (2): 187- 203.) Using 2_ [N, N- two – ( 2-chloroethyl) amino] -2,6-dimethyl-acetanilide and 3- (2-methoxyphenoxy) -2-propanol of the -I-, amino cyclization to synthesize the desired product. The advantage of this method is to avoid the use of large amounts of piperazine, but the drawback is six steps required to complete the reaction step is long, the total yield is low, is not applicable to industrial production. Route II: literature (US, 4567264; LI Shu-chun Chinese Journal of Medicinal Chemistry, 2003, 13 (5): 283-285) piperazine used directly as the raw material, the advantage of a four-step reaction process is shorter, but due to the direct use of piperazine N- (2,6- dimethylphenyl) -2-chloro – acetamide (2) the reaction, in order to avoid generating disubstituted compound and increased the yield dropping proportion piperazine, piperazine need to consume a large amount. Route III: Document (Qin Mingli, Xinyang Normal University, 2007,20 (2): 226-229) synthetic routes and route only difference is that two different priorities on the piperazine ring substituted on. After two routes have two places noteworthy: how to avoid the generation of disubstituted compounds and the compound (4), (it) is purified.

Synthesis of Compound (3)

In the synthesis of the compound (3), since piperazine simultaneous introduction of two groups, by changing the reaction conditions, to seek optimal reaction molar ratio, in order to optimize the synthesis process, to improve the yield. Since the formation of crystalline anhydrous piperazine water easily precipitated in the solvent methylene chloride, anhydrous conditions so the need to control and make the feed ratio of I: 2 Avoid disubstituted product formation. Methanol can also be used as solvent to avoid precipitation of piperazine, and generates less disubstituted, but did not significantly increase yield (61.5%), it is still producing less toxic with methylene chloride as the solvent, control anhydrous conditions. Removed by filtration and the compound (3) excess piperazine, after the solvent is evaporated, dissolved in water, filtered off disubstituted extracted with methylene chloride, in high purity in the latter studies, may be mono-substituted piperazine as the raw material, and then and then removing the protecting group, thereby avoiding the generation of double substitution also improves the yield.

Synthesis [0008] Compound (5)

When the use of trifluoroacetic acid deprotection, since the compound (4) itself has two salt-forming groups, so the need to increase the TFA feeding, paper, compound (4): trifluoroacetic acid = 1: 6 feeding, the reaction was stirred at room temperature for two hours after the end, and then try to solvent evaporated to dryness, a small amount of ethyl acetate was added and then repeatedly evaporated with divisible trifluoroacetic acid. Finally ethanol: petroleum ether = 1: 1.4 was recrystallized to give compound (5).

Synthesis [0009] Compound (I),

Document (Mcaroon, J Med Chem, 1981,24 (11): 1320- 1328) with methanol – toluene system, literature (US, 4567264) with DMF system. Considering the safety, environmental protection, price, cost, industrial production and other factors, we use isopropyl alcohol as a solvent. In this step, less side reaction byproducts concentrated in raw materials, in strict accordance with the reaction so after molar ratio, TLC detection, should be enough to make up the raw materials, to minimize raw material residues, reducing the difficulty of recrystallization.

[0010]

Specific implementation methods

Synthesis below with embodiments of the present invention will be further described in Example a N- (2,6- dimethylphenyl) -2-chloroacetamide (2)

In 3000ml three-neck flask, into 2,6-dimethylaniline (45. 53 g, 0. 375 mol), toluene (750 ml), sodium carbonate (39. 75g, 0. 375 mol), water (750 ml ), with vigorous stirring slowly added dropwise chloroacetyl chloride (50. 90 g, 0. 45mol), temperature 20~35 ° C (ice water bath). During the reaction, TLC detection reaction process. After completion of the reaction, ice-water bath cooling and crystallization, filtration, washed with toluene, recrystallized from 50% ethanol to give the compound (2), white needles (64. 53g, yield of 86. 9%, mp: 148 ~149 ° C).

Synthesis Example Two N-BOC’s [0011] implementation

In three 250ml flask inputs piperazine (3. 07g, 0. 0356mol), dichloromethane 50ml, piperazine with vigorous stirring to dissolve. Was slowly added dropwise while piperazine (2. 99g, 0. 0347mol dissolved in 50ml of methylene chloride), a BOC anhydride (7. 30g, was dissolved in 50ml of methylene chloride), temperature (Γ 5 ° C. After the addition was complete, the reaction was stirred overnight .TLC detection process. after completion of the reaction, a white solid was filtered off. the filtrate was concentrated, dissolved in water IOOml, a white solid was filtered off. the filtrate with dichloromethane (50ml X3 times). the organic layer was dried over anhydrous sodium sulfate , the drying agent was removed by filtration and the filtrate evaporated to give the compound (3), white needle crystals 4. 07g, yield 65. 3%, 1H-NMR (CDCL3):.. 3. 75 (s, 4H), 2 86 ~2. 91 (m, 4H,), I. 99 Cs, 1H), I. 45 (s, 9H).

[0012] Example (2,6-dimethylphenyl) Synthesis of (N-B0C piperazinyl) acetamide (4) of the three N- -1-.

[0013] In 150ml three-necked flask was added N-BOC piperazine (3) (5. 40g, O. 0289mol), the compound (2) (5. 71g, 0.0289mo, potassium carbonate (4. OOgO. 0202mol) in dry ethanol 10ml, was heated 4h, TLC detection progress of the reaction. after completion of the reaction, water was added 10ml, extracted with ethyl acetate (30mlX2). The organic layer was dried over anhydrous sodium sulfate, filtered off and the filtrate was concentrated and dried U. homogeneous, with ethyl .: petroleum ether = 1: 32 recrystallized compound (4) (white solid, 8 Olg, yield 79. 6%, mp: 119~120 ° C; 1H-NMR3 (s, 7. 09, 3H, Ar-H), 3. 50 (q, 4H, J = 4. 8), 3. 22 (s, 2H), 2.64 (q, 4H, J = 4.8), 2. 23 (s, 6H, 2 X CH3), 1.611 (s, 9H, 3X CH3);.. 13CNMR (167.95,154.43,134.78,133.35,128.14,127.08,79.83,61.65,53.40,43.37,26 24,18 47).

[0014] Fourth Embodiment N- (2,6-dimethylphenyl) -1-piperazine acetamide put in 50ml round bottom flask N- (2,6-dimethylphenyl) -1 – (N-BOC piperazine) -acetamide (4) (. 4 30g, O. 121mol), trifluoroacetic acid (8. 24g, 0 0722mol.), ethyl acetate 6ml, was stirred at room temperature under reflux for 2h, TLC detection reaction process . After completion of the reaction, the solvent evaporated to dryness to give a white solid. With ethanol: petroleum ether = 1: 14 recrystallized compound

(5), a white powder (2. 82g, yield 92. 5%, mp:. 130~131 .., 1H-NMR3 9. 573 (s, IN-H), 9 043 (s, 2XN- H), 7 · 187~7. 087 (t, 3X Ar-H), 3. 66 (s, 4H), 3. 27 (s, 2H), 3. 07 (s, 4Η) ^ _

2. 142 (s, 6Η, 2 X CH3).

Four cases of ranolazine dihydrochloride (I) Synthesis of [0015] implementation

In three 150ml round bottom flask was added the compound (3) (5. OOg, O. 02mol), isopropyl alcohol (35. Oml), was slowly added dropwise at the reflux temperature of the compound (5) (4. 14g, 0. 023mol ), continued under reflux conditions I. 5h, TLC detection progress of the reaction, the reaction was complete, cooled and added to the reactor 9. Oml 12mol / L of concentrated hydrochloric acid solution was adjusted to pH 2 and concentrated to near dryness to give bright yellow brown liquid, repeatedly adding ethanol, rotary evaporation to a white solid. Absolute ethanol and recrystallized to give compound (the I), as a white solid (6. 80g, yield 78. 7%, mp: 217 ~219 ° C (Dec) j1H-NMR (DMS0-d6): 10. 17 ( s, 1H, -CONH-), 7.21 ~6.87 (m, 7H, Ar-H), 4. 42 (m, 1H, -OCH2CHCH2-), 4. 23 (s, 2H, -CH2N), 4. 00 ~3.92 (m, 2H, -OCH2CHCH2), 3. 77 (s, 3H, -OCH3), 2. 67~2. 50 (m, 8H, 2 X -NCH2CH2N-), 2. 33 ~I. 91 ( m, 2H, -OCH2CHCH2), 2. 17 (s, 6H, 2 X CH3); MS (m / e): 427. 54).

CLIP

An in silico modelling based biocatalytic approach for the synthesis of drugs and drug intermediates in enantiopure forms is a rationalized methodology over the organo-chemical routes. In this study, enzyme-ligand based docking was carried out using (RS)-ranolazine, as the model drug for the screening of a suitable biocatalyst for the kinetic resolution of the racemic drug. The differential interaction of the two enantiomers with the lipase was analyzed on the basis of docking score and H-bond interaction with the amino acid residues, which helped to define the trans-esterification mechanism. Ranolazine [N-(2,6-dimethylphenyl)-2-[4-(2-hydroxy)-3-(2-methoxyphenoxy)propylpiperazin-1-yl]acetamide], an anti-anginal drug, significantly reduces the frequency of anginal attack and has also been used for the treatment of ventricular arrhythmias, and bradycardia. Various lipases were examined via computational as well as wet lab screening and Candida antartica lipase in the form of CLEA was the most efficient one for the (S)-selective kinetic resolution of (RS)-ranolazine, with highest conversion and enantiomeric excess. This is the first report of the chemo-enzymatic synthesis of (S)-ranolazine where the whole drug molecule was used for lipase catalysis. The present study showed that the combination of in silico studies and a classical wet lab approach could change the paradigm of biocatalysis.

CLIP

https://www.researchgate.net/publication/259824588_Synthesis_of_Ranolazine_Derivatives_Containing_the_1_S_4_S_-25-Diazabicyclo221Heptane_Moiety_and_Their_Evaluation_as_Vasodilating_Agents

OTHER NMR…….http://onlinelibrary.wiley.com/store/10.1111/cbdd.12285/asset/supinfo/cbdd12285-sup-0001-SupplementaryData.pdf?v=1&s=1c11a72432d0627b201f1bd37dab7ef913b0ff1f

OF Epimer (S,S,S)-5, Epimer (S,S,R)-5

PATENT

WO-2016142819

Ranolazine is marketed under the brand name Ranexa® and is indicated for the treatment of chronic angina. Ranexa may be used with beta-blockers, nitrates, calcium channel blockers, anti-platelet therapy, lipid-lowering therapy, ACE inhibitors, and angiotensin receptor blockers. Ranolazine is a racemic mixture, chemically described as 1-piperazineacetamide, N-(2, 6-dimethylphenyl)-4-[2-hydroxy-3-(2-methoxyphenoxy) propyl]-, (±)- indicated by compound of formula (1).

(1)

U.S. Patent No. 4,567,264 teaches two methods for the preparation process of Ranolazine. Method 1 disclosed reaction of 2-methoxyphenol compound of formula (2) with epichlorohydrin in presence of water, dioxane and NaOH to obtain l-(2-methoxyphenoxy)-2, 3-epoxypropane compound of formula (3) which is condensed with piperazine in presence of ethanol to obtain 2-(2-methoxyphenoxy)-l-(piperazin-l-yl) ethanol compound of formula (4). Reacting 2, 6-Dimethylaniline compound of formula (5) with chloroacetyl chloride in presence of TEA and MDC to obtain 2-chloro-N-(2,6-dimethylphenyl) acetamide compound of formula (6). Compound of formula (4) was condensed with compound of formula (6) in presence of dimethylformamide to obtain Ranolazine compound of formula (1). The method (1) is depicted below as scheme (I).

Scheme (I) (1)

US ‘264 taught another method for preparation of Ranolazine by condensing compound of formula (6) with piperazine in presence of ethanol to obtain N-(2, 6-dimethylphenyl)-2-(piperazin-l-yl) acetamide compound of formula (7). Compound of formula (3) was condensed with compound of formula (7) in presence of mixture of methanol and toluene at reflux temperature. The obtained Ranolazine is purified by column chromatography on silica gel. Excess of hydrochloric acid in methanol was added to get dihydrochloride salt of Ranolazine which was converted into its free base by suspending it in ether and stirred with excess of dilute aqueous potassium carbonate to get Ranolazine free base. The scheme is depicted below by Scheme (II).

Scheme (II) (!)

EP0483932A1 disclosed condensation of condensation of N, N-bis (2-chloro ethyl)-amino]-2,6-dimethyl acetanilide compound of formula (9) with l-[3-(2-methoxyphenoxy)-2-hydroxy]propylamine compound of formula (8) to obtain Ranolazine base. The base was purified by column chromatography; hydrochloride salt was formed by treating with methanolic HCI. The detailed impurity profile study was not reported for Ranolazine. The synthetic scheme is depicted below in scheme (III).

Chinese patent application No.102875490 disclosed condensation of compound of formula (6) with N-Boc-piperazine to obtain compound of formula (10) in the presence of K₂CO₃ in EtOH, removal of Boc group by means of TFA in EtOAc gives compound of formula (7) which is then converted into Ranolazine. The synthetic scheme is depicted below in scheme (IV).

Scheme (IV)

Organic Process Research & Development 2012, 16, 748-754 disclosed condensation of compound of formula (6) with piperazine in methanol to produce compound of formula (7), in which unwanted solid bis alkylated compound of formula (11) was filtered. The resulting filtrate pH adjusted to 5.0-5.5 with 44% phosphoric acid solution to recover piperazine monophosphate monohydrate salt. The compound of formula (7) was extracted with MDC.

PCT application No. 2008/047388 disclosed a process for the preparation Ranolazine, by reacting 2, 6-dimethyl aniline with Chloroacetyl chloride in the presence of base in water. The resulting amide intermediate is reacted with piperazine, and the resulting piperazine derivative is further condensed with l-(2-methoxyphenoxy)-2,3-epoxypropane in an inert solvent to produce crude Ranolazine, which is further purified by crystallizing from organic solvents selected from alcohols or aromatic hydrocarbons. Ranolazine obtained in the disclosed art does not have satisfactory purity for pharmaceutical use. Unacceptable amounts of impurities are generally formed along with Ranolazine. In addition, the processes involve the additional step of column chromatographic purifications, which are generally undesirable for large-scale operations.

As described above the cited literature processes suffer from many drawbacks like use of excess amount of piperazine during the reaction, which is difficult to handle in large scale; generation of large amount of effluent due to excessive use of piperazine, that is difficult to recover and recycle; Ranolazine obtained as an oil is difficult to handle in large scale production and laborious chromatographic

techniques are used for purification of Ranolazine.

It is observed that pharmaceutically acceptable salts of Ranolazine when prepared from impure Ranolazine do not meet the pharmaceutical acceptable quality. There is therefore, an unfulfilled need to provide industrially feasible process for the preparation of Ranolazine free base and its acid addition salt with high purity. The present invention provides Ranolazine of high purity by using phosphate salt of piperazine to prepare Ranolazine. In this process, excess of unreacted piperazine is easy to recover and recycle in the next reactions. Thus it is easy to avoid the generation of large amount of effluent due to reuse of piperazine, which are generally desirable for large-scale operations thereby making the process commercially feasible.

All the available literature uses unprotected piperazine and protected piperazine leading to formation of dimer impurities which are difficult to remove from the product and also resulting in poor overall yield of the product. The maximum daily dosage of Ranolazine is 2 g; therefore, known and unknown impurities must be controlled below 0.05% in the final drug substance.

From the above known fact our main target is:

1. To study the detailed impurity profile to and to control the formation of all the impurities below the desired limit (NMT 0.05%).

2. To obtained the Cost effective process by utilizing the maximum consumption of piperazine in the form of piperazine monophosphate salt there by reducing formation of unwanted impurities and also reusing recovered piperazine.

All the available literature uses unprotected piperazine and protected piperazine leading to formation of dimer impurities which are difficult to remove from the product and also resulting in poor overall yield of the product.

EXAMPLES

The following examples are presented for illustration only, and are not intended to limit the scope of the invention or appended claims.

Example 1 :

Preparation of [(2, 6-Dimethylphenyl)-amino carbonyl methyl) chloride (6)

To 0.74 kg of potassium carbonate and 2.51ml of water, was added. 500 gm of 2,6-Dimethyl aniline in 1.25 L of Acetone at 0-5 °C. 650 gm of Chloroacetyl chloride was added to the reaction mixture below 5 °C and stirred for 3 hrs. 2500 ml of water was added, stirred for 1 hr, filtered the product, washed with water and dried at 75 °C to get [(2,6- Dimethylphenyl)-amino carbonyl methyl] chloride (6). Yield: 95%; purity >98%

Example 2:

Preparation of l-(2-Methoxy phenoxy)-2, 3-epoxy propane (3)

Added 2.5 L of water to R.B Flask, 80 gms of NaOH was added and stirred to dissolve. Added 500 gms of Guaiacol, 1.12 Kg of Epichlorohydrine and stirred at 25-350C for 5-6 h. The organic layer was separated. To the Epichlorohydrine layer charged 160 gms NaOH dissolved in 2.5 L of water and stirred at 25-30°C for 3-4 h. The organic layer was separated and washed with 150 gms NaOH dissolved in 1.5 L of water. Excess Epichlorohydrine was recovered by distillation of the product layer at 90°C under vacuum (600-700 mmHg) to give 650-680 gms of oil. To the crude oil was added 3.0 L of Isopropanol and cooled to 0°C and filtered the product to get l-(2- Methoxy phenoxy)-2,3-epoxy propane (3).

Yield: 80%; purity >98%.

Example 3:

Preparation of piperazine monophosphate monohydrate

Added 1000 ml of water to R.B Flask 109 gms piperazine was added and stirred to dissolve. pH was adjusted to 5.0-5.5 with O-phosphoric acid. After stirring for 1-2-h at room temperature. Filtered the reaction mass and solid was isolated as piperazine monophosphate monohydrate.

Example 4:

Preparation of compound of formula (7)

Added 1000 ml of water to R.B Flask. 109 gms piperazine was added and stirred to dissolve. pH was adjusted to 5.0-5.5 with O-phosphoric acid. After stirring for 1-2- h at room temperature. Filtered the reaction mass and solid was isolated as piperazine monophosphate monohydrate and charged further to R.B Flask containing 1000 ml water. 100 gms of [(2,6-Dimethylphenyl)-amino carbonyl methyl)chloride (6) was added and heated the reaction mixture at reflux temperature for 7-8 h. Cooled the reaction mixture at 25-30°C and adjusted the pH to 5.5-6.0 with dilute sodium hydroxide solution filtered. Filtrate was washed with 100 ml x 2 methylene chloride and further basified with dilute sodium hydroxide solution and extracted with 500 ml x 3 methylene chloride to obtained compound of formula (7).

Example 5:

Preparation of Ranolazine

Added 1000 ml of water to R.B Flask 109 gms piperazine was added and stirred to dissolve. pH was adjusted to 5.0-5.5 with O-phosphoric acid, 100 gms of [(2,6-Dimethylphenyl)-amino carbonyl methyl)chloride (6) was added and heated the reaction mixture at reflux temperature for 7-8 h. Cooled the reaction mixture at 25-30°C and adjusted pH to 5.5-6.0 with dilute sodium hydroxide solution and filtered. Filtrate was washed with 100 ml x 2 methylene chloride and further basified with dilute sodium hydroxide solution and extracted with 500 ml x 3 methylene chloride. Combined organic layer was washed with saturated brine solution and 80 gm of l-(2-Methoxy phenoxy)-2, 3-epoxy propane (3) was added. Distilled out Methylene chloride under reduced pressure, added 500 ml methanol and refluxed for 5-6 h. Cooled the reaction mass to room temperature and added 500 ml water and cooled to 0°C. Filtered the product to get crude Ranolazine. Yield: 80%; purity >99%.

Example 6:

Preparation of Ranolazine from recovered piperazine monophosphate monohydrate

Added 1000 ml of water to R.B Flask 109 gms piperazine was added and stirred to dissolve. Added recovered piperazine monophosphate monohydrate and pH was adjusted to 5.0-5.5 with O-phosphoric acid, 100 gms of [(2,6-Dimethylphenyl)-amino carbonyl methyl)chloride (6) was added and heated the reaction mixture at reflux temperature for 7-8 h. Cooled the reaction mixture at 25-30°C and adjusted pH 5.5-6.0 with dilute sodium hydroxide solution and filtered. Filtrate was washed with 100 ml x 2 methylene chloride and further basified with dilute sodium

hydroxide solution and extracted with 500 ml x 3 methylene chloride. Combined organic layer was washed with saturated brine solution and 80 gm of l-(2-Methoxy phenoxy)-2,3-epoxy propane (3) was added. Distilled out Methylene chloride under reduced pressure, added 500 ml methanol and refluxed for 5-6 h. Cooled the reaction mass to room temperature and added 500 ml water and cooled to 0°C. Filtered the product to get crude Ranolazine. Yield: 80%; purity >99%.

Example 7:

Preparation of Ranolazine.

Added 1000 ml of water to R.B Flask 109 gms piperazine was added and stirred to dissolve. pH was adjusted to 5.0-5.5 with O-phosphoric acid. 100 gms of [(2,6-Dimethylphenyl)-amino carbonyl methyl)chloride (6) was added and heated the reaction mixture at reflux temperature for 7-8 h. Cooled the reaction mixture at 25-30°C, adjusted pH to 5.5-6.0 with dilute sodium hydroxide solution and filtered. Filtrate was washed with 100 ml x 2 methylene chloride and further basified with dilute sodium hydroxide solution and extracted with 500 ml x 3 methylene chloride. Combined organic layer was washed with saturated brine solution and 80 gm of l-(2-Methoxy phenoxy)-2,3-epoxy propane (3) was added. Distilled out Methylene chloride under reduced pressure, added 500 ml isopropyl alcohol, refluxed for 5-6 h. cooled the reaction mass to 0°C. Filtered the product to get crude Ranolazine. Yield: 80%; purity >98%.

Example 8:

Preparation of Ranolazine

Added 1000 ml of water to R.B Flask 109 gms piperazine was added and stirred to dissolve. pH was adjusted to 5.0-5.5 with O-phosphoric acid. After stirring for 1-2- h at room temperature. Filtered the reaction mass and solid was isolated as piperazine monophosphate monohydrate and charged further to R.B Flask containing 1000 ml water. 100 gms of [(2,6-Dimethylphenyl)-amino carbonyl methyl)chloride (6) was added and heated the reaction mixture at reflux temperature for 7-8 h. Cooled the reaction mixture at 25-30°C and adjusted the pH to 5.5-6.0 with dilute sodium hydroxide solution filtered. Filtrate was washed

with 100 ml x 2 methylene chloride and further basified with dilute sodium hydroxide solution and extracted with 500 ml x 3 methylene chloride. Combined organic layer was washed with saturated brine solution and 80 gm of l-(2-Methoxy phenoxy)-2,3-epoxy propane (3) was added. Distilled out Methylene chloride under reduced pressure, added 500 ml methanol and refluxed for 5-6 h. Cooled the reaction mass to room temperature, added 500 ml water, cooled to 0°C and filtered the product to get crude Ranolazine. Yield: 80%; purity >99%.

Example 9:

Purification of Ranolazine

Added 300 ml of methanol to R.B Flask, 100 gms of crude ranolazine piperazine and heated to dissolve. Added Activated charcoal and filtered the hot solution through hyflo and washed the hyflo with 100 ml methanol. Reaction mixture was cooled to room temperature. 200 ml water was added and was cooled further to 0-5°C. Filtered to afford pure Ranolazine. Yield: 90%; purity >99.9%.

PATENT

WO2006008753,

https://www.google.com/patents/WO2006008753A1?cl=en

US Patent 4567264 describes the preparation of Ranolazine base from basic stages by condensing [(2,6-dimethyphenyl) amino; carbonyl methyl] – chloride (II) with l-[3-(2-metlioxyphenoxy)-2- hydroxypropyl]piperazine.(III) The base was purified by column chromatography and isolated as oil. The hydrochloride salt was prepared in methanol using hydrochloric acid and the salt was isolated by addition of ether.

Ranolazine Base

EP 0483932 describes the preparation of Ranolazine base by condensation of α-[ N₃N -bis (2-cWoroetiiyl)-amino]-2,6-dimetliylacetanilide hydrochloride (IV) with l-[3-(2-methoxy phenoxy)-2-hydroxy]-propylamine (V). The base was purified using column chromatography and hydrochloride was formed by treating with metholic hydrochloric acid and crystallized by addition of diethyl ether as co solvent to obtain a product with melting point 229- 230 ⁰C.

Ranolazine base

It is a long standing need to avoid the formation of oil and obtain the product directly as solid there by eliminating laborious and expensive column chromatographic methods and achieving the higher yields of Ranolazine diliydrochloride. More over the prior art does not teach, any features such as polymorphic forms of the drug which may have varying pharmacological effects ^‘

Example-1:

Preparation of l-[3-(2-Metkoxyphenoxy)-2-hydroxypropyl ] piperazine

100 gms l-(2-methoxyphenoxy)-2,3-epoxypropane was added in a 60 min at 0-5 ⁰C to 192 gms of anhydrous piperazine dissolved in 500 ml methanol. Reaction mixture is stirred further for 2 Hrs at 0-5 ⁰C. It is quenched in 400 ml DMW & filtered. The product is obtained by extraction with MDC from the saturated aqueous layer with sodium chloride. 65 gms of acetic acid and 400 ml water is added in the MDC layer. Aqueous layers was separated and basified with 100 ml liquor ammonia. The product was extracted with 500 ml methylene dichloride and isolated by evaporation of solvent. The residue was used as such in the next reaction.

Yield =80 gms. HPLC purity = 96-$k %.

ExampIe-2 r-

Preparation of crude (+)-l-[3~(2-Methoxyphenoxy)-2-hydroxypropyl]-4- [N-(2,6-dimethylphenyl)carbamoylmethyl] piperazine dihydrochloride.

A mixture of 90 gms l-[3-(2-Memoxyphenoxy)-2-hydroxypropyl ] piperazine, 85 gms [(2,6-dimethylphenyl) aminocarbonyl methyl)chloride, 120 gms anhydrous potassium carbonate and 3.6 gms sodium iodide in 260 ml dimethyl formamide is stirred at room temperature (30-35 ⁰C) for 18 Hrs. The reaction mixture is quenched in 1600 ml water and extracted thrice with 300 ml methylene dichloride each time . Combined methylene dichloride layer is treated with a mixture of 1100 ml aqueous hydrochloric acid ( 35 %) & 900 ml water. Acidic aqueous layer is basified with ammonia, extracted with methylene dichloride and solvent is evaporated to get Ranolazine base. ; Yield = 140 gms ,

The above Ranolazine base is taken in 2160 j ml j acetone and 100 hydrochloric acid gas dissolved in isopropyl alcohol is added at room temperature till pH is acidic. The precipitated dihydrochloride compound is Filtered, is washed with acetone to give the Ranolazine dihydrochloride Yield = 144 gm.

Example-3 :-

Preparation of Crystalline (+)-l-[3-(2-Methoxyphenoxy)-2- hydroxypropyl]-4-[N-(2,6-diniethylphenyl)carbamoylmethyl] piperazine dihydrochloride.

100 gms of Crude (+)-l-[3-(2-Methoxyphenoxy)-2-hydroxypropyl]-4-[N- (2,6-dimemylplienyl)caitamoyhnetliyl] piperazine dihydrochloride is dissolved to get a clear solution in 500 ml methanol., The solution is cooled to room temperature and further cooled to 10⁰C. The product is filtered, washed with 2 X 50 ml methanol and dried at 75 degree C for 10 Hrs. get crystalline Form -A of Ranolazine diliydrochloride] ;: characterized .by XRD & DSC as shown in Figure |I and II.

Example-4: –

Preparation of Amorphouse (+)-l-[3-(2-Methoxyphenoxy)-2- hydroxypropyl]-4-[N-(2,6-dimethylphenyl)carbamoylmethyl] piperazine dihydrochloride

100 gms Ranolazine diliydrochloride is added in 500 ml water and heated to get a clear solution. Water is distilled off under reduced pressure, the residue is cooled to room temperature to obtain, amorphous form characterized by a XRD pattern (Figure III ) and DSC (Figure IV) exhibiting a broad endotherm around 80 and exotherm bet 220-224 and followed by endotherm 150-156 ⁰C.

Example-5: –

Preparation of Amorphouse ,(+)-l-[3-(J2-Methoxyphenoxy)-2- hydroxypropyl]-4-[N-(2,6-dimethylphenyl)carbampylitnethyl] piperazine dihydrochloride

100 gms Ranolazine dihydrochloride is added _;i| in 2000 ml ethanol containing 10 % water and heated to get a clear: solution. Solvent is distilled off under reduced pressure, the residue is cooled to room temperature to obtain amorphous form characterized by a XRD pattern (Figure m ) and DSC (Figure IV) exhibiting a broad endotherm around 80 and exotherm bet 220-224 and followed by endotherm 150-156 ⁰C.

Example -6:~

Preparation of Ranolazine base from its di hydrochloride salt

20 gms Ranolazine dihydrohloride at room temperature is added to a mixture containing 150 ml water and 50 ml acetone and 20 ml liquor ammonia. It is stirred for two hrs. The precipitated base, was _. filtered and dried under vacuum at 70 ⁰C to get crystalline form of Ranolazine base characterized by XRD & DSC as shown in Figure V & VI. Yield = 12 gms.

CLIP

Improved Process for Ranolazine: An Antianginal Agent†

References

External links

• Ranexa (ranolazine) Official Patient Website

RANEXA (ranolazine) Extended-release Tablets

Ranolazine is a racemic mixture, chemically described as 1-piperazineacetamide, N-(2,6-dimethylphenyl)-4-[2-hydroxy-3-(2-methoxyphenoxy)propyl]-, (±)-. It has an empirical formula of C₂₄H₃₃N₃O₄, a molecular weight of 427.54 g/mole, and the following structural formula:

Ranolazine is a white to off-white solid. Ranolazine is soluble in dichloromethane and methanol; sparingly soluble in tetrahydrofuran, ethanol, acetonitrile, and acetone; slightly soluble in ethyl acetate, isopropanol, toluene, and ethyl ether; and very slightly soluble in water.

RANEXA tablets contain 500 mg or 1000 mg of ranolazine and the following inactive ingredients: carnauba wax, hypromellose, magnesium stearate, methacrylic acid copolymer (Type C), microcrystalline cellulose, polyethylene glycol, sodium hydroxide, and titanium dioxide. Additional inactive ingredients for the 500 mg tablet include polyvinyl alcohol, talc, Iron Oxide Yellow, and Iron Oxide Red; additional inactive ingredients for the 1000 mg tablet include lactose monohydrate, triacetin, and Iron Oxide Yellow.

Ranolazine

Systematic (IUPAC) name
(RS)-N-(2,6-Dimethylphenyl)-2-[4-[2-hydroxy-3-(2-methoxyphenoxy)-propyl]piperazin-1-yl]acetamide
Clinical data
AHFS/Drugs.com	Monograph
MedlinePlus	a606015
License data	EU EMA: Ranexa US FDA: Ranolazine
Pregnancy category	US: C (Risk not ruled out)
Routes of administration	By mouth (tablets)
Legal status
Legal status	US: ℞-only
Pharmacokinetic data
Bioavailability	35 to 50%
Protein binding	~62%
Metabolism	Extensive in liver (CYP3A,CYP2D6) and intestine
Biological half-life	7 hours
Excretion	Renal (75%) and fecal (25%)
Identifiers
CAS Number	142387-99-3
ATC code	C01EB18 (WHO)
PubChem	CID 56959
IUPHAR/BPS	7291
DrugBank	DB00243
ChemSpider	51354
UNII	A6IEZ5M406
ChEBI	CHEBI:87681
ChEMBL	CHEMBL1404
Chemical data
Formula	C24H33N3O4
Molar mass	427.537 g/mol
Chirality	Racemic mixture
SMILES O=C(Nc1c(cccc1C)C)CN3CCN(CC(O)COc2ccccc2OC)CC3

////////////////////Ranolazine, 盐酸雷诺嗪 ,雷诺嗪 , Antianginal

Structure credit http://lgmpharma.com/eteplirsen-still-proves-efficacious-duchenne-drug/

FDA grants accelerated approval to first drug for Duchenne muscular dystrophy
New therapy addresses unmet medical need

The U.S. Food and Drug Administration today approved Exondys 51 (eteplirsen) injection, the first drug approved to treat patients with Duchenne muscular dystrophy (DMD). Exondys 51 is specifically indicated for patients who have a confirmed mutation of the dystrophin gene amenable to exon 51 skipping, which affects about 13 percent of the population with DMD.

Read more. 

Release

The U.S. Food and Drug Administration today approved Exondys 51 (eteplirsen) injection, the first drug approved to treat patients with Duchenne muscular dystrophy (DMD). Exondys 51 is specifically indicated for patients who have a confirmed mutation of the dystrophin gene amenable to exon 51 skipping, which affects about 13 percent of the population with DMD.

“Patients with a particular type of Duchenne muscular dystrophy will now have access to an approved treatment for this rare and devastating disease,” said Janet Woodcock, M.D., director of the FDA’s Center for Drug Evaluation and Research. “In rare diseases, new drug development is especially challenging due to the small numbers of people affected by each disease and the lack of medical understanding of many disorders. Accelerated approval makes this drug available to patients based on initial data, but we eagerly await learning more about the efficacy of this drug through a confirmatory clinical trial that the company must conduct after approval.”

DMD is a rare genetic disorder characterized by progressive muscle deterioration and weakness. It is the most common type of muscular dystrophy. DMD is caused by an absence of dystrophin, a protein that helps keep muscle cells intact. The first symptoms are usually seen between three and five years of age, and worsen over time. The disease often occurs in people without a known family history of the condition and primarily affects boys, but in rare cases it can affect girls. DMD occurs in about one out of every 3,600 male infants worldwide.

People with DMD progressively lose the ability to perform activities independently and often require use of a wheelchair by their early teens. As the disease progresses, life-threatening heart and respiratory conditions can occur. Patients typically succumb to the disease in their 20s or 30s; however, disease severity and life expectancy vary.

Exondys 51 was approved under the accelerated approval pathway, which provides for the approval of drugs that treat serious or life-threatening diseases and generally provide a meaningful advantage over existing treatments. Approval under this pathway can be based on adequate and well-controlled studies showing the drug has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit to patients (how a patient feels or functions or whether they survive). This pathway provides earlier patient access to promising new drugs while the company conducts clinical trials to verify the predicted clinical benefit.

The accelerated approval of Exondys 51 is based on the surrogate endpoint of dystrophin increase in skeletal muscle observed in some Exondys 51-treated patients. The FDA has concluded that the data submitted by the applicant demonstrated an increase in dystrophin production that is reasonably likely to predict clinical benefit in some patients with DMD who have a confirmed mutation of the dystrophin gene amenable to exon 51 skipping. A clinical benefit of Exondys 51, including improved motor function, has not been established. In making this decision, the FDA considered the potential risks associated with the drug, the life-threatening and debilitating nature of the disease for these children and the lack of available therapy.

Under the accelerated approval provisions, the FDA is requiring Sarepta Therapeutics to conduct a clinical trial to confirm the drug’s clinical benefit. The required study is designed to assess whether Exondys 51 improves motor function of DMD patients with a confirmed mutation of the dystrophin gene amenable to exon 51 skipping. If the trial fails to verify clinical benefit, the FDA may initiate proceedings to withdraw approval of the drug.

The most common side effects reported by participants taking Exondys 51 in the clinical trials were balance disorder and vomiting.

The FDA granted Exondys 51 fast track designation, which is a designation to facilitate the development and expedite the review of drugs that are intended to treat serious conditions and that demonstrate the potential to address an unmet medical need. It was also granted priority review and orphan drug designation.Priority review status is granted to applications for drugs that, if approved, would be a significant improvement in safety or effectiveness in the treatment of a serious condition. Orphan drug designation provides incentives such as clinical trial tax credits, user fee waiver and eligibility for orphan drug exclusivity to assist and encourage the development of drugs for rare diseases.

The manufacturer received a rare pediatric disease priority review voucher, which comes from a program intended to encourage development of new drugs and biologics for the prevention and treatment of rare pediatric diseases. This is the seventh rare pediatric disease priority review voucher issued by the FDA since the program began.

Exondys 51 is made by Sarepta Therapeutics of Cambridge, Massachusetts.

CAS 1173755-55-9 [RN]

eteplirsen [INN] [USAN] [Wiki]

eteplirsén [Spanish] [INN]

étéplirsen [French] [INN]

eteplirsenum [Latin] [INN]

этеплирсен [Russian] [INN]

إيتيبليرسان [Arabic] [INN]

Eteplirsen

Systematic (IUPAC) name
(P-deoxy-P-(dimethylamino)](2′,3′-dideoxy-2′,3′-imino-2′,3′-seco)(2’a→5′)(C-m5U-C-C-A-A-C-A-m5U-C-A-A-G-G-A-A-G-A-m5U-G-G-C-A-m5U-m5U-m5U-C-m5U-A-G),5′-(P-(4-((2-(2-(2-hydroxyethoxy)ethoxy)ethoxy)carbonyl)-1-piperazinyl)-N,N-dimethylphosphonamidate) RNA
Clinical data
Routes of administration	Intravenous infusion
Legal status
Legal status	Investigational
Identifiers
CAS Number	1173755-55-9
ATC code	None
ChemSpider	34983391
UNII	AIW6036FAS
Chemical data
Formula	C364H569N177O122P30
Molar mass	10305.738

///////////Exondys 51, Sarepta Therapeutics, Cambridge, Massachusetts, eteplirsen,  Orphan drug designation, Priority review, fast track designation, Duchenne muscular dystrophy, этеплирсен ,  إيتيبليرسان ,

Pimavanserin

• MF C₂₅H₃₄FN₃O₂
• MW 427.555

Pimavanserin, ACP 103, ACP-103; BVF-048

N-(4-fluorophenylmethyl)-N-(1-methylpiperidin-4-yl)-N’-(4-(2-methylpropyloxy)phenylmethyl)carbamide,

706779-91-1 (Pimavanserin )
706782-28-7 (Pimavanserin Tartrate)

For treatment of psychotic symptoms in patients with Parkinson’s disease

WATCH OUT AS THIS POST IS UPDATED………..

Trade Name：Nuplazid^®

MOA：5-HT2A inverse agonist

Indication：Hallucinations and delusions associated with Parkinson’s disease psychosis

Company：Acadia (Originator)

APPROVED US FDA 2016-04-29, ACADIA PHARMS INC, (NDA) 207318

To treat hallucinations and delusions associated with psychosis experienced by some people with Parkinson’s disease

	706782-28-7 (tartrate)

Urea, N-[(4-fluorophenyl)methyl]-N-(1-methyl-4-piperidinyl)-N’-[[4-(2-methylpropoxy)phenyl]methyl]-, (2R,3R)-2,3-dihydroxybutanedioate (2:1)

Pimavanserin Tartrate was approved by the U.S. Food and Drug Administration (FDA) on Apr 29, 2016. It was developed by Acadia, then marketed as Nuplazid^® by Acadia in US.

Pimavanserin Tartrate is a 5-HT_2A receptor inverse agonists, used to treat hallucinations and delusions associated with psychosis experienced by some people with Parkinson’s disease.

Nuplazid^® is available as tablet for oral use, containing 17 mg of pimavanserin. Recommended dose is 34 mg, taken orally as two tablets once daily.

Pimavanserin (INN), or pimavanserin tartate (USAN), marketed under the trade name Nuplazid, is a non-dopaminergic atypical antipsychotic^[2] developed by Acadia Pharmaceuticals for the treatment of Parkinson’s disease psychosis and schizophrenia. Pimavanserin has a unique mechanism of action relative to other antipsychotics, behaving as a selective inverse agonist of theserotonin 5-HT_2A receptor, with 40-fold selectivity for this site over the 5-HT_2C receptor and no significant affinity or activity at the5-HT_2B receptor or dopamine receptors.^[1] The drug has met expectations for a Phase III clinical trial for the treatment ofParkinson’s disease psychosis,^[3] and has completed Phase II trials for adjunctive treatment of schizophrenia alongside anantipsychotic medication.^[4]

Pimavanserin is expected to improve the effectiveness and side effect profile of antipsychotics.^[5][6][7] The results of a clinical trial examining the efficacy, tolerability and safety of adjunctive pimavanserin to risperidone and haloperidol were published in November 2012, and the results showed that pimavanserin potentiated the antipsychotic effects of subtherapeutic doses ofrisperidone and improved the tolerability of haloperidol treatment by reducing the incidence of extrapyramidal symptoms.^[8]

On September 2, 2014, the United States Food and Drug Administration granted Breakthrough Therapy status to Acadia’s New Drug Application for pimavanserin.^[9] It was approved by the FDA to treat hallucinations and delusions associated with psychosis experienced by some people with Parkinson’s disease on April 29, 2016.^[10]

Clinical pharmacology

Pimavanserin acts as an inverse agonist and antagonist at serotonin 5-HT_2A receptors with high binding affinity (K_i 0.087 nM) and at serotonin 5-HT_2C receptors with lower binding affinity (K_i 0.44 nM). Pimavanserin shows low binding to σ₁ receptors (K_i 120 nM) and has no appreciable affinity (K_i >300 nM) to serotonin 5-HT_2B, dopaminergic (including D₂), muscarinic, histaminergic, oradrenergic receptors, or to calcium channels.^[2]

Pimavanserin tartrate, 1-(4-fluorobenzyl)-3-(4-isobutoxybenzyl)-1-(1-methylpiperidin-4-yl)urea L-hemi-tartrate, has the following chemical structure:

Pimavanserin tartrate was developed by Acadia Pharmaceuticals and was approved under the trade name NUPLAZID® for use in patients with Parkinson’s disease psychosis.

Pimavanserin free base and its synthesis are disclosed in US 7,601,740 (referred to herein as US ‘740 or the ‘740 patent) and US 7,790,899 (referred to herein as US ‘899 or the ‘899 patent). US ‘740 discloses the synthesis of Pimavanserin free base (also referred to herein as“Compound A”), which includes O-alkylation followed by ester hydrolysis, and then in situ azidation. This process suffers from low process safety, and utilizes the hazardous reagent diphenylphosphoryl azide. The process is illustrated by the following Scheme 1.

Scheme 1:

US ‘899 describes another process, which includes O-alkylation followed by aldehyde reductive amination to obtain an intermediate which is then reacted with the hazardous reagent phosgene. This process is illustrated by the following Scheme 2:

Scheme 2:

Both of the above processes for the preparation of Pimavanserin include a reaction between 1-isobutoxy-4-(isocyanatomethyl)benzene, a benzyl isocyanate intermediate, and N-(4-fluorobenzyl)-1-methylpiperidin-4-amine. Processes for preparing benzyl isocyanate derivatives are generally described in the literature, such as in US ‘740; US ‘899; Bioorganic & Medicinal Chemistry, 21(11), 2960-2967, 2013; JP 2013087107; Synthesis (12), 1955-1958, 2005; and Turkish Journal of Chemistry, 31(1), 35-43, 2007. These processes often use the hazardous reagents like phosgene derivatives or diphenylphosphoryl azide.

synthetic route:

First, reduction of the ketone and a secondary amine to amine condensation after S-3 . 4- hydroxybenzaldehyde etherification, followed by condensation with hydroxylamine to give the oxime S-. 7 , which is then reduced by hydrogenation to the amine S-. 8 , S.8- light gas reaction to give the isocyanate S-. 9 , S. 9- react with the primary amine can be obtained Nuplazid ( pimavanserin ).Kg product can be obtained by this route.

WO2006036874

https://www.google.com/patents/WO2006036874A1?cl=en

Example 1 : Preparation of N-(4-fluorobenzyl)-N-( 1 -methylpiperidin-4-yl)-N’ -( 4-(2- methylpropyloxy)phenylmethyl)carbamide a) Preparation of

Tπacetoxy borohydπde (6.5 kg) was added over 1.5 h to a solution of N- methylpiperid-4-one (3.17 kg) and 4-fluorobenzylamme (3.50 kg) in methanol (30 1), maintaining the temperature under 27 ⁰C. The reaction mixture was stirred for 15 h at 22 ⁰C. The residual amine was checked by gel chromatography (4-fluorobenzylamine: < 5%). A solution of 30% sodium hydroxide (12.1 kg) in water (13.6 kg) was added in 75 minutes (min) maintaining the temperature under 20 ⁰C. Methanol was distilled off to a residual volume of 26 litters. Ethyl acetate was added (26 L), the solution was stirred for 15 min, the phases were decanted over 15 min and the lower aqueous phase was discarded. Ethyl acetate was distilled under reduced pressure from the organic phase at 73-127 ⁰C. At this stage the residue was mixed with a second crude batch prepared according to this method. The combined products were then distilled at 139-140 ⁰C / 20 mbar to yield 11.2 kg product (> 82%). b) Preparation of

4-Hydroxybenzaldehyde (4.0 kg) and ethanol (20 1) were added to a solution of isobutyl bromide (9.0 kg) in ethanol (15 1). Potassium carbonate (13.6 kg) was added and the suspension was refluxed (74-78 ⁰C) for 5 days. The residual 4- hydroxybenzaldehyde was checked by HPLC (< 10%). The suspension was cooled to 20 ⁰C and used in the next step.

c) Preparation of

] Hydroxylamine (50% in water, 8.7 kg) was added to the product from previous step b)(174 1, 176 kg) and ethanol (54 1). The suspension was refluxed (77 ⁰C) for 3 h. Unreacted residual amounts of the compound of step b was checked by HPLC (< 5%). The suspension was cooled to 30 ⁰C, filtered and the filter was washed with ethanol (54 1). The solution was concentrated by distillation under reduced pressure at 30 ⁰C to a residual volume of 67 litters. The solution was cooled to 25 ⁰C and water (110 1) was added. The suspension was concentrated by distillation under reduced pressure at 30 ⁰C to a residual volume of 102 litters. Petrol ether (60-90 fraction, 96 1) was added and the mixture was heated to reflux (70 ⁰C). The solution Λvas cooled to 40 ⁰C and crystallization was initiated by seeding. The suspension was cooled to 5 ⁰C and stirred for 4h. The product was centrifuged and the cake was washed with petrol ether (60-90 fraction, 32 1). The wet cake was dried at about 40 ⁰C to yield 16kg product (63%).

d) Preparation of

[0105] The product from previous step c) (15.7 kg) was dissolved in ethanol (123 1). Acetic acid (8.2 kg) and palladium on charcoal 5% wet (1.1 kg) were added. The oxime was hydxogenated at 22 ⁰C and 1.5 bar for 4h. Consumption of oxime was checked by HPLC (for information). The catalyst was filtered and the solvent was distilled under reduced pressure at 36 ⁰C to a final volume of 31 1. Ethyl acetate (63 1) was added and the mixture was heated to reflux (75 ⁰C) until dissolution. The solution was cooled to 45 ⁰C and the crystallization was initiated by seeding. The suspension was cooled to 6-10 ⁰C and stirred for 2.5h. The product was centrifuged and the cake was washed with 2 portions of ethyl acetate (2 x 0.8 1). The wet cake was dried at a temperature of about 40 ⁰C to yield 8 kg (41%).

e) Preparation of

Aqueous sodium hydroxide (30%, 5.0 kg) was added to a suspension of the product from previous step d) (7.9 kg) in heptane (41 1). The solution was heated to 47 ⁰C, stirred for 15 mm and decanted o~ver 15 mm. The pH was checked (pH>12) and the aqueous phase was separated. The solvent was removed by distillation under reduced pressure at 47-65⁰C. Heptane was added (15 1) and it was removed by distillation under reduced pressure at 58-65 ⁰C. Heptane was added (7 1), the solution was filtered and the filter was washed with heptane (7 1). The solvent was removed by distillation under reduced pressure at 28-60 ⁰C. Tetrahydrofuran (THF, 107 1) and tπethylamme (TEA, 6.8 kg) were added and the temperature was fixed at 22 ⁰C. In another reactor, phosgene (5.0 kg) was introduced in tetrahydrofuran (88 1) previously cooled to -3 ⁰C. The THF and TEA s olution was added to the solution of phosgene in 3h 50 mm maintaining the temperature at -3 ⁰C. The reactor was washed with tetrahydrofuran (22 1). The mixture was stirred for 45 min at 20 ⁰C and then for 90 min at reflux (65 ⁰C). The solvent was distilled under reduced pressure at 25-30 ⁰C to a residual volume of 149 1. The absence of phosgene was controlled. At this stage, there still was phosgene and the suspension was degassed by bubbling nitrogen through it. After this operation the level of phosgene above the solution was below 0.075 ppm. The suspension was filtered and washed with tetrahydrofuran (30 1). The solvent was distilled under reduced pressure at 20-25 ⁰C to a residual volume of 40 1. Tetrahydrofuran (51 1) was added and the solvent was distilled under reduced pressure at 20-25 ⁰C to a residual volume of 40 1. The final volume was adjusted to about 52 litters by addition of tetrahydrofuran (11 1). The solution was analysed and used in the next step. f) Preparation of the title compound of formula I

The product from previous step e) (51 1) was added in 1 h to a solution of the product from step a) (7.3 kg) in tetrahydrofuian (132 1) at 17 ⁰C. The line was washed with tetrahydrofuran (12 1) and the mixture was stirred for 15h. Residual product from the first step was checked by HPLC The solvent was removed ^“by distillation under reduced pressure at 20-38 ⁰C to a residual volume of 165 1. Charcoal (Noπt SXl-G, 0 7 kg) was added, the mixture was stirred for 15 mm and filtered. The lme was washed with tetrahydrofuran (7 1) and the solvent was removed by distillation under reduced pressure at 20-25 ⁰C to a residual volume of 30 1. Isopropyl acetate (96 1) was added to obtain a solution of the title compound of formula I, which contains a small amount of impurities, which were mainly side products from the previous reactions. Removal of the solvent from a sample yields a substantially amorphous solid

g) Preparation of N-(4-fluorobenzyl)-N-(l-methylpipeπdm-4-yl)-N’-(4-(2-methylpropyloxy)phe- nylmethyl)carbamide hemi-tartrate

To the solution of the compound of Formula I in isopropyl acetate (96 1) from step f was added at 23 ⁰C a previously prepared solution of tartaric acid (1 7 kg) in water (1.7 1) and tetrahydrofuran (23 1) The residual suspension was stirred for 2.5 days at 22 ⁰C The tartrate crude product was centrifuged and the cake was washed with 4 portions of isopropyl acetate (4 x 23 1). A total of 107 kg of mother liquors was saved for later use in obtaining the tartrate salt The wet cake was dπed at about 40 ⁰C to yield 8.3 kg (50%) product.

h) First Purification

The tartrate crude product of step g) (8.1 kg) was dissolved m demmeralized water (41 1) at 22 ⁰C. Isopropyl acetate (40 L), 30% aqueous sodium hydroxide (4.3 kg) and sodium chloride (2 kg) were added. The pH was checked (>12) and the solution was stirred for 15 mm. The solution was decanted over 15 mm and the aqueous phase was separated. The aqueous phase was re-extracted with isopropyl acetate (12 1) Demmeralized water (20 1) and sodium chloride (2 0 kg) were added to the combined organic phases, the solution was stirred for 15 mm, decanted over 15 mm and the aqueous phase was discarded. Charcoal (0.4 kg) was added, the mixture was stirred for 20 mm and filtered. After a line wash with isopropyl acetate (12 1), the solvent was removed under reduced pressure at 20-25 ⁰C Heptane (49 1) was added and the suspension was stirred for 15 mm at 40 °C. Then, 8 1 of solvent was removed by distillation under reduced pressure at 38-41 ⁰C The slurry was cooled to 20 ⁰C and stirred for 1 h. The product was centrifuged and the cake was washed with heptane (5 1) The wet compound of Forrnu-la I (5.5 kg) was dissolved m ethanol (28 1) at 45 ⁰C. A solution of tartaric acid (0.72 kg) m ethanol (11 1) was added at 45 ⁰C and the line was washed with ethanol (91). The solution was cooled to 43 ⁰C, seeded with the tartrate salt of the compound o f Formula I, then the slurry was cooled to 35⁰C m 30 mm, stirred at this temperature for 1 h and cooled to -5 ⁰C After 14 h at this temperature the product was centrifuged and washed with two portions of ethanol (2×6 1) The wet cake was dried at about 45 ⁰C for 76 h to yield 4 kg of the herm-tartrate

i) Re -crystallization

150 O g of herm-tartrate obtained m h) was dissolved under stirring at 65 ⁰C m 112 ml absolute ethanol and then cooled under stirring to 48 ⁰C at a cooling rate of 1 °C/mm Crystallization started after a few minutes at this temperature and the suspension turned to a thick paste withm 1 h. The suspension was heated again to 60 ⁰C and then cooled to 48⁰C at a rate of 1 °C/mm The obtained suspension was stirred and was cooled to 15 ⁰C at a cooling rate of 3 °C/h. The crystalline precipitate was separated by filtration and the bottle was washed with 10 ml absolute ethanol cooled to 5 ⁰C. The crystalline residue was dried under vacuum and 40 ⁰C for 50 hours to yield 146 g crystalline pure herm-tartrate.

j) Second purification

15 78 g of the tartrate salt prepared from step i) was dissolved 121 130 ml water 500 ml TBME was added and the pH -was adjusted to 9 8 by addition of 2 ISf NaOH solution. After precipitation of a white solid, the aqueous phase was extracted 5 times by 500 ml TBME The organic phases were concentrated until a volume of about 400 ml remained. The solution was stored at 6⁰C. The precipitate was filtered, washed with TBME and finally dried m vacuum for 5 hours. Yield: 8.24 g of a white poΛvder. The mother liquor was concentrated to a fourth and stored at 6⁰C. The precipitate was filtered and dried m vacuum for 18 hours. Yield: 1.6 g of a white powder.

PXRD revealed a crystalline compound of formula I. No Raman peaks from tartaric acid were found. The first scan of DSC (-50⁰C to 210⁰C₅ 10°K/mm) revealed a melting point at 123.6°C. Above about 19O⁰C, the sample started to decompose. Example 2. Preparation of N-(4-fluoroben2yl)-N-(l-methylpiperidin-4-yl)-N’-(4-(2- methylpropγloxy)phenylmethyl)carbamide citrate of formula FV

a) 90 mg of the product from Example 1 and 40 mg citnc acid were suspended m 5.0 ml ethylacetate. The suspension was stirred at 60 ⁰C for 15 minutes (mm), cooled to 23±2 ⁰C, and then stored for 30 mm at 23±2 ⁰C. The precipitate was filtered off and dried in air for 30 mm to yield 52 mg of a crystalline white powder. Optical microscopy shows that the obtained solid was crystalline

b) 182 mg of the product from Example 2 and 78.4 mg citric acid were suspended m 10.0 ml ethyl acetate The suspension was stirred at 60 ⁰C for 30 mm, then stirred at 40 ⁰C for 90 mm, and finally stirred for 60 mm at 23 ⁰C The suspension was filtered and washed with heptane, yielding 237 mg of a white crystalline powder -with an endothermic peak near 153 ⁰C (enthalpy of fusion of about 87 J/g), determined by differential scanning caloπmetry at a rate of 10K/mm (DSC). Thermogravimetry (TG-FTIR) showed a mass loss of about 0.7% between 60 and 160 ⁰C, which was attributed to absorbed water Decomposition started at about 170 ⁰C Solubility m water was about 14 mg/ml The crystalline powder remained substantially unchanged when stored for 1 week at 60 ⁰C and about 75% r_h. m an open container (HPLC area was 99.4% compared to reference value of 99.9%). Elemental analysis and ¹H-NMR complies with an 1 : 1 stoichiometry.

PATENT

http://www.google.im/patents/WO2008144326A2?cl=en

Example 1 : Preparation of N-(4-fluorobenzyl)-N-Cl-methylpiperidin-4-yl)-N’-(^‘4-f2- methylpropyloxy)phenylmethγl)carbamide a) Preparation of

Triacetoxy borohydride (6.5 kg) was added over 1.5 h to a solution of N- methylpiperid-4-one (3.17 kg) and 4-fluorobenzylamine (3.50 kg) in methanol (30 L) maintaining the temperature under 27 ⁰C. The reaction mixture was stirred for 15 h at 22 ⁰C. The residual amine was checked by gel chromatography (4-fluorobenzylamine: < 5%). A solution of 30% sodium hydroxide (12.1 kg) in water (13.6 kg) was added in 75 minutes (min) maintaining the temperature under 20 ⁰C. Methanol was distilled off to a residual volume of 26 litres. Ethyl acetate was added (26 L), the solution was stirred for 15 min, the phases were decanted over 15 min and the lower aqueous phase was discarded. Ethyl acetate was distilled under reduced pressure from the organic phase at 73-127 ⁰C. At this stage the residue was mixed with a second crude batch prepared according to this method. The combined products were then distilled at 139-140 ⁰C / 20 mbar to yield 11.2 kg product (> 82%). b) Preparation of

4-Hydroxybenzaldehyde (4.0 kg) and ethanol (20 L) were added to a solution of isobutyl bromide (9.0 kg) in ethanol (15 L). Potassium carbonate (13.6 kg) was added and the suspension was refluxed (74-78 ⁰C) for 5 days. The residual 4- hydroxybenzaldehyde was checked by HPLC (< 10%). The suspension was cooled to 20 °C and used in the next step.

c) Preparation of

[0117] Hydroxylamine (50% in water, 8.7 kg) was added to the product from previous step b) (174 L₅ 176 kg) and ethanol (54 L). The suspension was refluxed (77 ⁰C) for 3 h. Unreacted residual was checked by HPLC (< 5%). The suspension was cooled to 30 °C, filtered and the filter was washed with ethanol (54 L). The solution was concentrated by distillation under reduced pressure at 30 ⁰C to a residual volume of 67 litters. The solution was cooled to 25 ⁰C and water (1 10 L) was added. The suspension was concentrated by distillation under reduced pressure at 30 °C to a residual volume of 102 litters. Petrol ether (60-90 fraction, 96 L) was added and the mixture was heated to reflux (70 °C). The solution was cooled to 40 ⁰C and crystallization was initiated by seeding. The suspension was cooled to 5 ⁰C and stirred for 4h. The product was centrifuged and the cake was washed with petrol ether (60-90 fraction, 32 L). The wet cake was dried at about 40 °C to yield 16kg product (63%). d) Preparation of

The product from previous step c) (15.7 kg) was dissolved in ethanol (123 L). Acetic acid (8.2 kg) and palladium on charcoal 5% wet (1.1 kg) were added. The oxime was hydrogenated at 22 ⁰C and 1.5 bar for 4h. Consumption of oxime was checked by HPLC. The catalyst was filtered and the solvent was distilled under reduced pressure at 36 °C to a final volume of 31 L. Ethyl acetate (63 L) was added and the mixture was heated to reflux (75 ⁰C) until dissolution. The solution was cooled to 45 ⁰C and the crystallization was initiated by seeding. The suspension was cooled to 6-10 °C and stirred for 2.5h. The product was centrifuged and the cake was washed with 2 portions of ethyl acetate (2 x 0.8 L). The wet cake was dried at a temperature of about 40 ⁰C to yield 8 kg (41%).

e) Preparation of

Aqueous sodium hydroxide (30%, 5.0 kg) was added to a suspension of the product from previous step d) (7.9 kg) in heptane (41 L). The solution was heated to 47 °C, stirred for 15 min and decanted over 15 min. The pH was checked (pH>12) and the aqueous phase was separated. The solvent was removed by distillation under reduced pressure at 47-65 °C. Heptane was added (15 L) and then removed by distillation under reduced pressure at 58-65 ⁰C. Heptane was added (7 L), the solution was filtered, and the filter was washed with heptane (7 L). The solvent was removed by distillation under reduced pressure at 28-60 ⁰C. Tetrahydrofuran (THF, 107 L) and triethylamine (TEA, 6.8 kg) were added and the temperature was fixed at 22 ⁰C. In another reactor, phosgene (5.0 kg) was introduced in tetrahydrofuran (88 L) previously cooled to -3⁰C. The THF and TEA solution was added to the solution of phosgene in 3h 50 min, maintaining the temperature at – 3 ⁰C. The reactor was washed with tetrahydrofuran (22 L). The mixture was stirred for 45 min at 20 ⁰C and then for 90 min at reflux (65 ⁰C). The solvent was distilled under reduced pressure at 25-30 ⁰C to a residual volume of 149 L. The absence of phosgene was controlled. At this stage, phosgene was still present and the suspension was degassed by bubbling nitrogen through it. After this operation, the level of phosgene above the solution was below 0,075 ppm. The suspension was filtered and washed with tetrahydrofuran (30 L). The solvent was distilled under reduced pressure at 20-25 ⁰C to a residual volume of 40 L. Tetrahydrofuran (51 L) was added and the solvent was distilled under reduced pressure at 20- 25 ⁰C to a residual volume of 40 L. The final volume was adjusted to about 52 litters by addition of tetrahydrofuran (1 1 L). The solution was analysed and used in the next step.

f) Preparation of the title compound of formula I

The product from previous step e) (51 L) was added in 1 h to a solution of the product from step a) (7.3 kg) in tetrahydrofuran (132 L) at 17 ⁰C. The line was washed with tetrahydrofuran (12 L) and the mixture was stirred for 15h. Residual product from the first step was checked by HPLC. The solvent was removed by distillation under reduced pressure at 20-38 ⁰C to a residual volume of 165 L. Charcoal (Norit SXl-G₅ 0.7 kg) was added, the mixture was stirred for 15 min and filtered. The line was washed with tetrahydrofuran (7 L) and the solvent was removed by distillation under reduced pressure at 20-25 ⁰C to a residual volume of 30 L. Isopropyl acetate (96 L) was added to obtain a solution of the title compound of formula I, which contains a small amount of impurities (mainly side products from the previous reactions.) Removal of the solvent from a sample yields a substantially amorphous solid.

The solution with the crude product was used for the direct preparation of the hemi-tartrate and simultaneously for the purification of the free base via the hemi-tartrate through crystallization from suitable solvents.

Example 5: Preparation of the hemi-tartrate of formula IV from crude free base of formula I

Crude product according to Example l(f) (4.3 kg) was dissolved at 45 ⁰C in ethanol (23 L). A solution of (+)-L-tartaric acid (0.58 kg) in ethanol was added at 45 ⁰C and the line was washed with 6 L of ethanol. The solution was stirred for 20 min (formation of solid precipitate) and the slurry was cooled to 35 ⁰C over 30 min. The slurry was stirred at this temperature for 1 hour and then cooled to -5 ⁰C. After 14 hours stirring at this temperature, the product was centrifuged and washed with 2 portions of ethanol (2 x 4 L). The wet cake was dried at 45 ⁰C for 80 hours yielding 3.3 kg of product (85%, based on tartaric acid). PXRD of the product revealed that polymorph A was formed.

PATENT

WO2014085362A1.

CN101031548A

CN101035759A

CN102153505A

CN1816524A

US2008280886A1.

WO0144191

PATENT

WO-2016141003

Scheme 4:

The reaction depicted in Scheme 4 can be carried out in a suitable organic solvent such as acetone at rather mild conditions (e.g.40-50°C). If necessary, the R¹ substituent may subsequently be converted to an isobutoxy group to obtain Pimavanserin or a salt thereof.

An overview about certain processes for preparation of Pimavanserin is shown in Scheme 5 below.

Scheme 5:

Compound A L-Tartaric acid

Hemi-tartrate salt *Compound A is Pimavanserin

Scheme 10:

^{Compound 1 Compound 2 Pimavanserin}

Scheme 13:

An overview about synthetic routes to Pimavanserin via Compound XVI is shown in the following Scheme 14:

Scheme 14:

Example 16: Preparation of hemi-tartrate salt of Pimavanserin

To a 25 mL seal tube, equipped with a stir bar, was charged 344.4 mg of the above crude PMV (1.0 mmol in theory), 75 mg of L-tartaric acid (FW: 150.09, 0.5 mmol, 0.5 equiv.), and 7 mL (16.4 vol.) of absolute ethanol. The tube was sealed and heated to 70°C to afford a clear solution, then cooled down gradually to room temperature. The product precipitated, and the batch was further cooled down to 0-5°C and stirred at this temperature for 0.5 hour. The product was collected by vacuum filtration, and the filter cake was washed with 2 × 1 mL (2.3 vol.) of EtOH. The product was dried in the Buchner funnel under vacuum overnight, affording 177.6 mg of salt, representing a 35.4% yield in 99.6 A% purity. 1H NMR (CDCl₃, 400 MHz): δ = 1.01 (d, J = 6.4 Hz, 6 H), 1.79-1.82 (m, 2H), 2.02-2.19 (m, 3H), 2.63 (brs, 5H), 3.38-3.47 (m, 2H), 3.67 (d, J = 6.4 Hz, 2H), 4.25 (d, J = 4.8 Hz, 2H), 4.32 (s, 1H), 4.38 (s, 2H), 4.58 (brs, 2H), 6.77 (d, J = 8.0 Hz, 2H), 6.95-6.99 (m, 4H), 7.17 (d, J = 7.2 Hz, 2H).

Example 21: Preparation of Pimavanserin via compound V as dihydrochloride salt

Step 1: Preparation of N-(4-fluorobenzyl)-1-methylpiperidin-4-amine dihydrochloride (Compound V x 2HCl)

The reaction was performed in 300 mL reactor. The reactor was purged with N₂, then Argon. 4-Fluorobenzylamine (10 g; 80 mmol, 1.0 eq) was dissolved in dry MeCN (100 mL), then 1-methylpiperidin-4-one (10.9 g; 96 mmol, 1.2 eq) was added and the reaction mixture was stirred at ambient temperature for 18h. Then, the reaction mixture was cooled to 0°C and 25.4 g of NaBH(OAc)₃ (25.4 g; 120 mmol, 1.5 eq) was added in portions over 20 min and the reaction was allowed to stir to room temperature. After 1h, the reaction was quenched by the addition of 200 ml of water, pH was adjusted to 2 with 5M HCl and then extracted using 3 x 250 mL of DCM. Basification of the aqueous layer to pH 9.5 with 30% sol. NaOH and extraction 3 x 300 ml of DCM followed. The organic layers were collected and dried over anh. Na₂SO₄, filtered and evaporated to dryness yielding 17.24 g (92%) of oily product, N-(4-fluorobenzyl)-1-methylpiperidin-4-amine (Compound V).

To a 250 mL, three necked, round bottom flask, equipped with a stir bar and thermometer, N-(4-fluorobenzyl)-1-methylpiperidin-4-amine (10 g; 0.045 mol) and DCM (50 mL) were charged and cooled to 10-15 °C. To the resulting solution, 5-6 N HCl in 2-PrOH (3 equiv., 0.135 mmol) was added dropwise over 25 min., white crystals formed, and the solution then cooled to 0-5 °C for 2 hours. Crystals were filtered off, washed with 50 mL of DCM, dried at 50°C/10 mbar for 10 hours yielding 12.8 g (96.4%) of N-(4-fluorobenzyl)-1-methylpiperidin-4-amine dihydrochloride (Compound V x 2HCl).

Step 2: Preparation of 4-isobutoxybenzaldehyde (Compound XIII)

4-Hydroxybenzaldehyde (10 g; 0.082 mol), potassium carbonate (33.95 g; 0.246 mol) and potassium iodide (1.36 g; 0.008 mol) were suspended in N,N-dimethylformamide (50 mL). Isobutyl bromide (26.7 mL; 0.246 mol) was added and the reaction was heated at 70°C under nitrogen for 3 hours. The reaction was cooled down, diluted by using 150 mL of water and extracted by using 300 mL of ethyl acetate. The organic layer was extracted five times by using 150 mL of 10% NaCl solution, dried under Na₂SO₄, filtered and concentrated which resulted in 14.3 g (98%) of yellow oily product of 4-isobutoxybenzaldehyde

(Compound XIII).

Step 3: Preparation of (4-isobutoxyphenyl)methanamine hydrochloride (Compound XI x HCl)

[0142] To a solution of 4-isobutoxybenzaldehyde (Compound XIII) (19.9 g; 0.112 mol) in methanol (90 mL), Raney nickel (6 g) and 7N methanol ammonia solution (90 mL) were added. The reaction mixture was stirred under hydrogen atmosphere (0.5 bar) at 10-15°C for 24 hours. The reaction solution was filtered through Celite to remove the catalyst. Methanol was distilled off and toluene (500 mL) was added. The solution was concentrated to 250 mL and 5-6 N HCl in 2-PrOH (30 mL; 0.15 mol) was added dropwise at ambient temperature. The resulting suspension was then cooled to 5 °C and stirred for additional 2 hours. Crystals were filtered off, washed with 60 mL of toluene, dried at 50°C/10 mbar for 10 hours yielding 20.88 g (86.7%) of (4-isobutoxyphenyl)methanamine hydrochloride (Compound XI x HCl). The product was analyzed by PXRD– form I was obtained, the PXRD pattern is shown in Figure 3.

Step 4: Option 1: Preparation of 1-(4-fluorobenzyl)-3-(4-isobutoxybenzyl)-1-(1-methylpiperidin-4-yl)urea (Pimavanserin

Part a: Preparation of Compound VI-a:

To a 250 mL, three necked, round bottom flask, equipped with a stir bar, condenser and thermometer, (4-isobutoxyphenyl)methanamine hydrochloride (Compound XI x HCl) (5 g, 0.023 mol), CDI (6.01 g; 0.037 mol) and acetonitrile (40 mL) were charged. The resulting solution was stirred for 1 h at 65-70 °C and monitored by HPLC until full conversion to Compound VI-a.

Part b: Preparation of Pimavanserin:

N-(4-fluorobenzyl)-1-methylpiperidin-4-amine (Compound V) (7.73 g; 0.035 mol) was added to Compound VI-a obtained above. After 2h, complete conversion was observed. Upon completion, the reaction solution was cooled to 50 °C and water was added dropwise in a 1:3 ratio (120 mL). After addition of a whole amount of water, crystals were formed and suspension was allowed to cool to ambient temperature. The crystals were filtered off, washed with 2 x 40 mL solution of CH₃CN:H₂O 1:3, then 40 mL of water, dried at 45°C/10 mbar for 10 hours yielding 9.35 g (94.4%) of 1-(4-fluorobenzyl)-3-(4-isobutoxybenzyl)-1-(1-methylpiperidin-4-yl)urea (Pimavanserin).

Step 4– option 2: Preparation of 1-(4-fluorobenzyl)-3-(4-isobutoxybenzyl)-1-(1-methylpiperidin-4-yl)urea (Pimavanserin)

Part a: Preparation of Compound VI-a:

To a 500 mL, three necked, round bottom flask, equipped with a stir bar, condenser and thermometer, (4-isobutoxyphenyl)methanamine hydrochloride (Compound XI x HCl) (10 g; 0.046 mol), CDI (11.28 g; 0.07 mol) and acetonitrile (100 mL) were charged. The resulting solution was stirred for 1 h at 65-70 °C and monitored by HPLC until full conversion to Compound VI-a.

Part b: Preparation of Pimavanserin:

[0146] The reaction solution containing Compound VI-a obtained above was cooled to 30°C and N-(4-fluorobenzyl)-1-methylpiperidin-4-amine dihydrochloride (Compound V x 2HCl) (20.53 g; 0.07 mol) and K₂CO₃ (9.61 g; 0.07 mol) were added. The reaction mixture was heated to 65-70 °C and stirred for next 18 hours. Upon completion, the reaction solution was cooled to 50 °C, pH of solution was adjusted to 10.5 with 6N NaOH solution, and water was added dropwise in ratio 1:3 (300 mL). After addition of a whole amount of water, crystals were formed, and suspension was allowed to cool to ambient temperature, and then cooled on ice-bath (0-5°C) for 1.5 hour. The crystals were filtered off, washed with 2 x 100 mL solution of CH₃CN:H₂O 1:3, then 100 mL of water, dried at 45°C/10 mbar for 10 hours yielding 18.797 g (95.6%) of 1-(4-fluorobenzyl)-3-(4-isobutoxybenzyl)-1-(1-methylpiperidin-4-yl)urea (Pimavanserin).

Example 26: One pot preparation of Pimavanserin (without isolation of Compound 1)

Step 1: Preparation of 2-(4-isobutoxyphenyl)acetic acid

To a 250 mL, 3 neck, round bottom flask, equipped with thermocouple and nitrogen sweep, was charged 10 g of 4-hydroxy phenyl acetic acid (Molecular weight (FW): 152.15, 65.7 mmol, 1.0 equiv.), 30 g of potassium carbonate (FW: 138.21, 216.8 mmol, 3.3 equiv.), 1.1 g of potassium iodide (KI, FW: 166, 6.57 mmol, 0.1 equiv.), followed by 100 mL (10 vol.) of DMF. After stirring for 5 minutes at room temperature, 15.7 mL of isobutyl bromide (FW: 137.02, 144.6 mmol, 2.2 equiv.) was charged into the batch. The mixture was then heated to 75°C and kept stirring at the same temperature for 2 days until no limited starting material remaining as determined by HPLC. The reaction was cooled down to room temperature, and quenched by charging with 100 mL of deionized (DI) water. The pH of the reaction mixture was adjusted to less than 1 by charging 100 mL of 2N HCl. The product was extracted with 150 mL of ethyl acetate. After partitioning, the upper organic layer was washed with additional 100 mL of DI water, concentrated to dryness on the rotary evaporator under vacuum. The residue was dissolved in 100 mL each of THF (10 vol) and DI water (10 vol). After charging 20 g of lithium hydroxide, the mixture was heated to reflux for 3 hours until complete reaction. The batch was cooled to room temperature, concentrated on rotary

evaporator to remove THF. The residue was acidified with 300 mL of 2N HCl and 45 mL of 6N HCl aqueous solution until pH <1. The product was extracted with 2×250 mL of methylene chloride, dried over sodium sulfate, and filtered on Buchner funnel. The filtrate was concentrated to dryness on rotary evaporator under vacuum to afford 10.18 g of 2-(4-isobutoxyphenyl)acetic acid, representing a 74.4% yield in 98.5 A% purity. ¹H NMR (d₆-DMSO, 400 MHz): δ = 0.97 (d, J = 6.8 Hz, 6 H), 1.96-2.02 (m, 1H), 3.47 (s, 2H), 3.71 (d, J = 6.4 Hz, 2H), 6.86 (d, J = 8.8 Hz, 2H), 7.14 (d, J = 8.8 Hz, 2H).

Step 2: Preparation of Pimavanserin

To a 50 mL, single neck, round bottom flask, equipped with thermocouple and nitrogen sweep, was charged 333.2 mg of 2-(4-isobutoxyphenyl)acetic acid (FW: 208.25, 1.6 mmol, 1.0 equiv.), 311.3 mg of CDI (FW: 162.15, 1.92 mmol, 1.2 equiv.), and 3.3 mL of CH₃CN (10 vol.). After stirring at room temperature for 1 hour, this was charged 139 mg (FW: 69.5, 2.0 mmol, 1.25 equiv.) of NH₂OH^.HCl and stirred for additional 15-18 hours at room temperature. Additional 518.9 mg of CDI (FW: 162.15, 3.2 mmol, 2.0 equiv.) was charged and the batch turned from a slurry to a clear solution again. This was followed by charging a solution of 334 mg of Compound V (FW: 222.3, 1.5 mmol, 0.94 equiv.), and heating up to 60 ^oC. The reaction was stirred at this temperature for approximately 5 hour before cooling back to room temperature. The reaction was quenched with 20 mL of DI water, and concentrated on rotary evaporator to remove acetonitrile. The aqueous residue was diluted with 40 mL of ethyl acetate, and washed with 2×20 mL of brine. The organic phase was concentrated to dryness on rotary evaporator under vacuum. The residue was purified by chromatography (160 g RediSep Alumina column), eluting with 0-5% of methanol in dichloromethane to afford 305 mg of Pimavanserin, representing a 47.6% yield in 99.3 A% purity.¹H NMR (CDCl₃, 400 MHz): δ = 1.01 (d, J = 6.8 Hz, 6 H), 1.62-1.73 (m, 4H), 2.03-2.09 (m, 3H), 2.25 (s, 3H), 2.84-2.87 (m, 2H), 3.68 (d, J = 6.4 Hz, 2H), 4.27-4.34 (m, 5H), 4.45-4.48 (m, 1H), 6.67-6.79 (m, 2H), 6.99-7.02 (m, 4H), 7.16-7.27 (m, 2H). HRMS-ESI (m/z): [M+1]⁺ Calcd for C₂₅H₃₅F₁N₃O₂: 428.2708; found 428.2723.

Example 27: Preparation of Pimavanserin (with isolation of Compound 1)

Step 1: Preparation of Compound 1

To a 100 mL, single neck, round bottom flask, equipped with thermocouple and nitrogen sweep, was charged 1 g of Compound XV (FW: 208.25, 4.8 mmol, 1.0 equiv.), 934.0 mg of CDI (FW: 162.15, 5.76 mmol, 1.2 equiv.), followed by 10 mL (10 vol.) of acetonitrile. After stirring for 45 minutes at room temperature, 417 mg of NH₂OH.HCl (FW: 69.5, 6.0 mmol, 1.25 equiv.) was charged into the batch. The mixture was kept stirring at the ambient temperature overnight and turned into a thick slurry. HPLC determined 1.6 A% of starting material remaining. The batch was diluted with 6 mL of acetonitrile (6 vol.) and 16 mL (16 vol.) of DI water, and cooled down to 0-5 ºC. After stirring at the same temperature for additional 1 hour, the batch was filtered on the Buchner funnel. The filter cake was washed with 2×10 mL (10 vol.) of DI water, and dried in the funnel under vacuum overnight to afford 774.1 mg of hydroxamic acid Compound 1, representing a 72% yield in 99.6 A% purity. ¹H NMR (CDCl₃, 400 MHz): δ = 0.96 (d, J = 6.8 Hz, 6 H), 1.95-2.02 (m, 1H), 3.19 (s, 2H), 3.70 (d, J = 6.4 Hz, 2H), 6.85 (d, J = 8.4 Hz, 2H), 7.14 (d, J = 8.4 Hz, 2H), 8.80 (s, 1H), 10.61 (s, 1H).

Step 2: Synthesis of Pimavanserin

To a 50 mL sealed tube, equipped with nitrogen sweep, was charged 250 mg of compound 1 (FW: 223.27, 1.12 mmol, 1.0 equiv.), 217.9 mg of CDI (FW: 162.15, 1.34 mmol, 1.2 equiv.), and 1.7 mL of acetonitrile (6.8 vol.). After stirring at room temperature for 40 minutes, the batch was heated to 60 ^oC and kept stirring at the same temperature for additional 10 minutes. This was followed by charging 373.5 mg of Compound 3 (FW: 222.3, 1.68 mmol, 1.5 equiv.). The container of Compound V was rinsed with 0.5 mL (2 vol.) of acetonitrile, and the wash was combined with the batch. The reaction was monitored by HPLC and complete in 2 hours. The batch was cooled down to room temperature, diluted with 5 mL (20 vol.) of ethyl acetate, which was washed with 3×5 mL (20 vol.) of DI water. After partitioning, the upper organic layer was concentrated to dryness on rotary evaporator. The residue was re-dissolved into 3 mL (12 vol.) of ethyl acetate after heating up to reflux to afford a slightly milky solution. This was charged with 12 mL (48 vol.) of heptane, and cooled down to 0-5^oC. The batch was kept stirring at the same temperature for 1 hour and filtered on a Buchner funnel. The filter cake was washed with 2×5 mL (20 vol.) of heptane, and dried in the funnel with a nitrogen sweep for 1 hour to afford 270.8 mg of Pimavanserin as a white solid, representing a 56.6% yield in 98.8 A% purity. ¹H NMR (CDCl₃, 400 MHz): δ = 1.01 (d, J = 6.8 Hz, 6 H), 1.62-1.73 (m, 4H), 2.03-2.09 (m, 3H), 2.25 (s, 3H), 2.84-2.87 (m, 2H), 3.68 (d, J = 6.4 Hz, 2H), 4.27-4.34 (m, 5H), 4.45-4.48 (m, 1H), 6.67-6.79 (m, 2H), 6.99-7.02 (m, 4H), 7.16-7.27 (m, 2H). HRMS-ESI (m/z): [M+1]⁺ Calcd for C₂₅H₃₅F₁N₃O₂: 428.2708; found 428.2723.

Example 34: Preparation of Pimavanserin from Compound 2

To a 25 mL, three neck, round bottom flask, equipped with a stir bar, condenser and thermocouple, Compound 2, 0.210 g, was charged (FW: 249.26, 0.84 mmol, 1.0 equiv.). This was followed 3 mL of acetonitrile, anhydrous, 99.8%. The mixture was stirred at 60°C for 4 h. Then, to the reaction mixture, Compound V, 0.375 g (FW: 222.30, 1.69 mmol, 2.0 equiv.), was added. After 1h, complete conversion was observed. The reaction was diluted with EtOAc (20 mL) and washed twice with a saturated solution of NH4Cl (2 x 15 mL), then H2O (10 mL) and finally with a saturated NaCl solution (10 mL). The organic layer was dried over anh. sodium sulfate, filtered and concentrated under partial vacuum to about 5 mL of EtOAc. To this solution, n-heptane (10 ml) was added with vigorous stirring, in a dropwise manner, over half an hour. A white precipitate was formed, followed by filtration and drying in vacuum at 45°C for 3h, affording 0.188 g of Pimavanserin. HPLC-MS (m/z) [M+1]+ 428.2; 1H NMR (CDCl3, 400 MHz): δ = 1.01 (d, J = 6.7 Hz, 6 H), 1.68-1.77 (m, 4H), 2.03-2.10 (m, 3H), 2.30 (s, 3H), 2.91-2.97 (m, 2H), 3.67(d, J = 6.7 Hz, 2H), 4.27 (d, J = 5.4 Hz, 2H), 4.31-4.43 (m, 3H), 4.50 (brt, J = 5.5 Hz, 1H), 6.74-6-79 (m, 2H), 6.95-7.05 (m, 4H), 7.14-7.22 (m, 2H).

Example 38: Preparation of Pimavanserin from Compound and Compound V x 2HCl

250 mL reactor was charged with N-hydroxy-2-(4-isobutoxyphenyl)acetamide (Compound 1) (10 g, 0.045 mol), CDI (10.53 g, 0.076 mol) and 100 mL of MeCN, p.a. The resulting solution was stirred for 1.5 h at 60-65 °C and monitored by HPLC. Upon full conversion to the corresponding isocyanate, reaction solution was cooled to 35 °C and N-(4- fluorobenzyl)-1-methylpiperidin-4-amine dihydrochloride (Compound V x 2HCl) (22.48 g, 0.065 mol) and K₂CO₃ (6.19 g, 0.045 mol) were added. Reaction mixture was heated up to 60-65 °C and stirred for 6 hours and followed by 17 h at ambient temperature.

Upon completion, the reaction solution was cooled to 20 °C and water was added dropwise in ratio 1:3 (300 mL) with adjustment of pH to 11 with 6N NaOH solution. After addition of whole amount of water, crystals were formed and suspension was stirred at 20 °C for 2 h and 0-5°C for next 2 hour. Crystals were filtered off, washed with 2 x 100 mL solution of MeCN:H₂O 1:3, then 100 mL of H₂O, dried at 30°C/10 mbar for 24 hours yielding 17.56 g (91.7%) of Pimavanserin.

PAPER

Bioorg. Med. Chem. Lett. 2015, 25, 1053–1056.

Bioorganic & Medicinal Chemistry Letters

Volume 25, Issue 5, 1 March 2015, Pages 1053–1056

Clip

THURSDAY Oct. 31, 2013 — Many people living with Parkinson’s disease suffer from hallucinations and delusions, but an experimental drug might offer some relief without debilitating side effects.

READ ALL AT

http://www.drugs.com/news/new-shows-early-promise-treating-parkinson-s-psychosis-48630.html

The drug — pimavanserin — appears to significantly relieve these troubling symptoms, according to the results of a phase 3 trial to test its effectiveness.

Pimavanserin (ACP-103) is a drug developed by Acadia Pharmaceuticals which acts as an inverse agonist on the serotonin receptor subtype 5-HT_2A, with 40x selectivity over 5-HT_2C, and no significant affinity or activity at 5-HT_2B or dopamine receptors.^[1] As of September 3 2009, pimavanserin has not met expectations for Phase III clinical trials for the treatment of Parkinson’s disease psychosis,^[2] and is in Phase II trials for adjunctive treatment of schizophrenia alongside an antipsychotic medication.^[3] It is expected to improve the effectiveness and side effect profile of antipsychotics.^[4][5][6]

3-D MODEL OF DRUG PIMAVANSERIN, THE DEVELOPMENT OF WHICH HAS BEEN EXPEDITED BY THE FDA

External links

• Nuplazid (pimavanserin) Official Site

References

1.  Friedman, JH (October 2013). “Pimavanserin for the treatment of Parkinson’s disease psychosis”. Expert Opinion on Pharmacotherapy. 14 (14): 1969–1975.doi:10.1517/14656566.2013.819345. PMID 24016069.
2. ^ Jump up to:^{a b c} “Nuplazid (pimavanserin) Tablets, for Oral Use. U.S. Full Prescribing Information” (PDF). ACADIA Pharmaceuticals Inc. Retrieved 1 May 2016.
3. Jump up^ ACADIA Pharmaceuticals. “Treating Parkinson’s Disease – Clinical Trial Pimavanserin – ACADIA”. Archived from the original on February 25, 2009. Retrieved 2009-04-11.
4. Jump up^ “ACADIA Announces Positive Results From ACP-103 Phase II Schizophrenia Co-Therapy Trial” (Press release). ACADIA Pharmaceuticals. 2007-03-19. Retrieved 2009-04-11.
5. Jump up^ Gardell LR, Vanover KE, Pounds L, Johnson RW, Barido R, Anderson GT, Veinbergs I, Dyssegaard A, Brunmark P, Tabatabaei A, Davis RE, Brann MR, Hacksell U, Bonhaus DW (Aug 2007). “ACP-103, a 5-hydroxytryptamine 2A receptor inverse agonist, improves the antipsychotic efficacy and side-effect profile of haloperidol and risperidone in experimental models”. The Journal of Pharmacology and Experimental Therapeutics. 322 (2): 862–70. doi:10.1124/jpet.107.121715.PMID 17519387.
6. Jump up^ Vanover KE, Betz AJ, Weber SM, Bibbiani F, Kielaite A, Weiner DM, Davis RE, Chase TN, Salamone JD (Oct 2008). “A 5-HT2A receptor inverse agonist, ACP-103, reduces tremor in a rat model and levodopa-induced dyskinesias in a monkey model”. Pharmacology, Biochemistry, and Behavior. 90 (4): 540–4. doi:10.1016/j.pbb.2008.04.010. PMC 2806670.PMID 18534670.
7. Jump up^ Abbas A, Roth BL (Dec 2008). “Pimavanserin tartrate: a 5-HT2A inverse agonist with potential for treating various neuropsychiatric disorders”. Expert Opinion on Pharmacotherapy. 9 (18): 3251–9.doi:10.1517/14656560802532707. PMID 19040345.
8. Jump up^ Meltzer HY, Elkis H, Vanover K, Weiner DM, van Kammen DP, Peters P, Hacksell U (Nov 2012). “Pimavanserin, a selective serotonin (5-HT)2A-inverse agonist, enhances the efficacy and safety of risperidone, 2mg/day, but does not enhance efficacy of haloperidol, 2mg/day: comparison with reference dose risperidone, 6mg/day”. Schizophrenia Research. 141 (2-3): 144–152. doi:10.1016/j.schres.2012.07.029. PMID 22954754.
9. Jump up^ “ACADIA Pharmaceuticals Receives FDA Breakthrough Therapy Designation for NUPLAZID™ (Pimavanserin) for Parkinson’s Disease Psychosis”. Press Releases. Acadia. 2014-09-02.
10. Jump up^ “Press Announcements — FDA approves first drug to treat hallucinations and delusions associated with Parkinson’s disease”. U.S. Food and Drug Administration. Retrieved1 May 2016.

NUPLAZID contains pimavanserin, an atypical antipsychotic, which is present as pimavanserin tartrate salt with the chemical name, urea, N-[(4-fluorophenyl)methyl]-N-(1-methyl-4-piperidinyl)-N’-[[4-(2- methylpropoxy)phenyl]methyl]-,(2R,3R)-2,3-dihydroxybutanedioate (2:1). Pimavanserin tartrate is freely soluble in water. Its molecular formula is (C₂₅H₃₄FN₃O₂)₂•C₄H₆O₆ and its molecular weight is 1005.20 (tartrate salt). The chemical structure is:

The molecular formula of pimavanserin free base is C₂₅H₃₄FN₃O₂ and its molecular weight is 427.55.

NUPLAZID tablets are intended for oral administration only. Each round, white to off-white, immediaterelease, film-coated tablet contains 20 mg of pimavanserin tartrate, which is equivalent to 17 mg of pimavanserin free base. Inactive ingredients include pregelatinized starch, magnesium stearate, and microcrystalline cellulose. Additionally, the following inactive ingredients are present as components of the film coat: hypromellose, talc, titanium dioxide, polyethylene glycol, and saccharin sodium.

WO2006036874A1 *	26 Sep 2005	6 Apr 2006	Acadia Pharmaceuticals Inc.	Salts of n-(4-fluorobenzyl)-n-(1-methylpiperidin-4-yl)-n’-(4-(2-methylpropyloxy)phenylmethyl)carbamide and their preparation
WO2006037043A1 *	26 Sep 2005	6 Apr 2006	Acadia Pharmaceuticals Inc.	Synthesis of n-(4-fluorobenzyl)-n-(1-methylpiperidin-4-yl)-n’-(4-(2-methylpropyloxy)phenylmethyl)carbamide and its tartrate salt and crystalline forms
WO2007133802A2 *	15 May 2007	22 Nov 2007	Acadia Pharmaceuticals Inc.	Pharmaceutical formulations of pimavanserin
US20060205780 *	3 May 2006	14 Sep 2006	Thygesen Mikkel B	Synthesis of N-(4-fluorobenzyl)-N-(1-methylpiperidin-4-yl)-N’-(4-(2-methylpropyloxy)phenylmethyl)carbamide and its tartrate salt and crystalline forms
US20060205781 *	3 May 2006	14 Sep 2006	Thygesen Mikkel B	Synthesis of N-(4-fluorobenzyl)-N-(1-methylpiperidin-4-yl)-N’-(4-(2-methylpropyloxy)phenylmethyl)carbamide and its tartrate salt and crystalline forms
US20070260064 *	15 May 2007	8 Nov 2007	Bo-Ragnar Tolf	Synthesis of n-(4-fluorobenzyl)-n-(1-methylpiperidin-4-yl)-n’-(4-(2-methylpropyloxy)phenylmethyl)carbamide and its tartrate salt and crystalline forms

Reference
1	*	WANG, Y. ET AL: “ACP-103: 5-HT2A receptor inverse agonist treatment of psychosis treatment of sleep disorders” DRUGS OF THE FUTURE , 31(11), 939-943 CODEN: DRFUD4; ISSN: 0377-8282, 2006, XP002446571

Pimavanserin

Systematic (IUPAC) name
N-(4-fluorophenylmethyl)-N-(1-methylpiperidin-4-yl)-N’-(4-(2-methylpropyloxy)phenylmethyl)carbamide
Clinical data
Trade names	Nuplazid
Routes of administration	Oral (tablets)
Legal status
Legal status	US: ℞-only
Pharmacokinetic data
Protein binding	94–97%[1]
Metabolism	Hepatic (CYP3A4, CYP3A5,CYP2J2)[2]
Biological half-life	54–56 hours[1]
Identifiers
CAS Number	706779-91-1  706782-28-7 (tartrate)
ATC code	None
PubChem	CID 10071196
DrugBank	DB05316
ChemSpider	8246736
UNII	JZ963P0DIK
KEGG	D08969
ChEBI	CHEBI:133017
ChEMBL	CHEMBL2111101
Synonyms	ACP-103
Chemical data
Formula	C25H34FN3O2
Molar mass	427.553 g/mol
SMILES[hide] CC(C)COc3ccc(cc3)CNC(=O)N(C(CC2)CCN2C)Cc(cc1)ccc1F

//////////Pimavanserin, FDA 2016,  Nuplazid®,  Acadia , Breakthrough Therapy, PRIORITY REVIEW, 

FDA approves Amjevita, a biosimilar to Humira

The U.S. Food and Drug Administration today approved Amjevita (adalimumab-atto) as a biosimilar toHumira (adalimumab) for multiple inflammatory diseases.

Read more.

Adalimumab
Farmaceutische gegevens
t1/2	10–20 dagen
Databanken
CAS-nummer	331731-18-1
ATC-code	L04AB04
DrugBank	BTD00049
Farmacotherapeutisch Kompas	Adalimumab
Chemische gegevens
Molaire massa	144190.3 g/mol

///////FDA, Amjevita, biosimilar, Humira, FDA 2016

WO-2016147120, AZILSARTAN, NEW PATENT, SMILAX Laboratories Ltd

(WO2016147120) AN IMPROVED PROCESS FOR THE PREPARATION OF SUBSTANTIALLY PURE AZILSARTAN

Azilsartan (I) is an angiotensin receptor II antagonist used in the treatment of hypertension. Angiotensin II causes vasoconstriction via an angiotensin II receptor on the cell membrane and elevates blood pressure.

Azilsartan medoxomil i.e. (5-methyl-2-oxo-l,3-dioxol-4-yl)methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid is developed by Takeda pharmaceuticals and is marketed under the trade name Edarbi. It was approved by USFDA on 25 Feb, 2011 and EMEA on 7 Dec 2011 for the treatment of high blood pressure in adults.

Azilsartan medoxomil and its salts thereof are imbibed with properties such as strong and long lasting angiotensin II antagonistic activity and hypotensive action which has an insulin sensitizing activity useful for the treatment of metabolic diseases such as diabetes and the like., and a useful agent for the prophylaxis or treatment of circulatory diseases such as hypertension, cardiac diseases, nephritis and stroke. Azilsartan medoxomil is the prodrug of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan).

Methods of preparing benzimidazole derivative useful as an angiotensin II receptor antagonist such as Azilsartan Medoxomil and salts thereof are disclosed by Takeda in US 5,243,054 (herein after referred as US ‘054 patent). The US’054 patent describes several synthetic routes for preparing Azilsartan. According to one of the synthetic process, the compound of formula II is reacted with hydroxylamine hydrochloride in a conventional organic solvent and sodium methoxide in methanol to give the amidoxime compound of formula III which on further reaction with ethyl chloroformate in presence of triethylamine base in refluxing xylene undergoes cyclization to provide a compound of formula IV. Azilsartan was prepared by hydrolysis of compound of formula IV in presence of lithium hydroxide by adjusting the pH with HC1. The process is as depicted below in Scheme A:

However, the amidoxime compound of formula III obtained by the above process contains about 50% of amide imputiy along with desired product, owing to the strong reaction conditions which impairs the quality and loss of yield. The pH adjustment with HC1 in the hydrolysis step of compound IV results in the formation of an undesired desethyl impurity of formula V due to acid sensitive nature of the ether linkage in the benzimidazole moiety of Azilsartan.

Formula V

According to another method disclosed in US’054 for the preparation of Azilsartan comprises by reacting ethoxycarboimidoyl biphenyl benzimidazole derivative of compound with ethyl chloroformate to give N-methoxycarbonyl ethoxycarboimidoyl biphenyl benzimidazole derivative, which is further converted to compound of formula IV and then to Azilsartan of formula I by hydrolysis.

According to one another embodiment method for the preparation of Azilsartan disclosed in US ‘054, cyanobiphenyl aminobenzoate derivative compound reacts with hydroxylamine hydrochloride in presence of triethylamine subsequently followed by addition of ethyl chlorocarbonate results in the formation of compound of formula IV which is further hydrolyzed to obtain Azilsartan of formula I.

J. Med. Chem. Vol. 39, No. 26, 5230-5237 (1996) describes the use of triethylamine as base during the conversion of compound of formula II to amidoxime compound of formula III and use of 2-ethylhexylchloroformate instead of ethylchloroformate as cyclizing agent.

Processes for the preparation of Azilsartan medoxomil and its potassium salt are described in US 7,157,584 which comprises reacting Azilsartan with 4-hydroxymethyl-5-methyl-l,3-dioxol-2-one in presence of dimethylacetamide, p-toluoyl sulfonylchloride, 4-dimethylaminopyridine and potassium carbonate.

PCT publication WO 2012/107814 discloses process for the preparation of Azilsartan or its esters or salts by reacting amidoxime compound of formula III with carbonyl source such as carbodiimides, dialkyl carbonate and phosgene equivalents in presence of a suitable base to obtain compound of formula IV which is further converted to Azilsartan and its pharmaceutically acceptable salts. The process for the preparation of Azilsartan is as depicted in Scheme B:

Scheme – B

This publication also discloses that use of a carbonyl source reduces the formation of the content of desethyl impurity during cyclization.

Polymorphs of Azilsartan and its salts are disclosed in WO 2013/044816 and WO 2013/186792.

All the above prior art methods for the preparation of Azilsartan have inherent disadvantages such as the usage of unsafe reagents, high boiling solvents, extreme reaction conditions invariably resulting in the formation of low pure intermediates as well as Azilsartan having a considerably higher content of desethyl impurity. Accordingly, there remains a need for the industrial preparation of substantially pure Azilsartan which is free of impurities with high yield.

Examples

Example-1: Preparation of Methyl-2-ethoxy-l-[[2′- ((hydroxycarbamimidoyl)biphenyl)-4-yl]methyl]-lH-benzimidazole-7-carboxylate (Formula-Ill):

To a stirred solution of DMSO (1500.0 mL), Hydroxylamine hydrochloride ( 126.7g 1.83mol) and Dipotassium hydrogen phosphate (634.9g 3.65mol) was added Methyl l-[[2′-cyanobiphenyl-4-yl]methyl]-2-ethoxybenzimidazole-7-carboxylate (lOO.Og 0.243mol) at 25-30°C. The reaction mass temperature was raised to 80-85°C and maintained for 30-40 hours. Reaction completion was monitored by TLC. Upon completion of reaction, reaction mass was cooled to 10- 15°C, and was poured into water (3000.0 mL), stirred for 45min at 20-25°C. and was filtered. The filtered wet solid was washed with water and dried at 65°C to get crude Methyl-2-ethoxy-l-[[(2′-(hydroxycarbarmrmdoyl)biphenyl-4-yl]methyl]-lH-benzimidazole-7-carboxylate. The wet material was slurried in Acetone (optional) at reflux and filtered at room temperature to obtain pure compound.

Yield: 79.92 g, 74.0%; HPLC Purity: 97.78%; Desethyl impurity: 0.318%; Amide impurity: 1.42%.

Example-2: Preparation of Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (Formula-IV) :

To the pre cooled solution of Methylene dichloride (375.0 mL) and Methyl-2-ethoxy-1 -[[2′ -((hydroxycarbamimidoyl)biphenyl)-4-yl] methyl]- lH-benzimidazole-7-carboxylate (75.0g, 0.168mol) was added ethyl chloroformate ( 18.3g 0.168mol)

followed by addition of triethylamine (18.75g 0.185mol). The reaction mass was maintained at 0-5 °C for about 1 hour. Upon completion of the reaction, reaction mass was poured into water (200.0 mL), organic layer was separated and washed with 5% NaHC0₃ solution (150.0 mL) and then with water (150.0 mL). The organic layer was dried over sodium sulfate and distilled to obtain the crude material (optionally be isolated using cyclohexane solvent). To this obtained crude material, ethyl acetate (750.0mL) and potassium carbonate (112.5g 0.814mol) were added and heated to reflux for 6 to 8 hours. The contents were cooled, filtered and wet solid was slurried in water. Wet material so obtained was slurried in ethyl acetate at reflux and filtered at room temperature and dried at 60-65°C to give Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate.

Yield: 64.27 g, 81.0 %; HPLC Purity: 99.80%; Desethyl impurity: 0.085%.

Example-3: Preparation of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

A mixture of 0.4N NaOH solution (395.8 mL) and Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (25. Og) were stirred at 50-55°C for period of 60min. The reaction mass was cooled to room temperature and the product layer was washed with ethyl acetate (125.0mL). pH of the separated aqueous product layer was adjusted to 4.0 to 5.0 using dilute acetic acid at 0-5 °C. The obtained solid material was filtered and washed with water (lOO.OmL). This material was dried to obtain the title product.

Yield: 20.0 g, 82.47%; HPLC Purity : 99.80%; Desethyl impurity: 0.10%.

Example-4: Preparation of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

A mixture of 0.4N NaOH solution (633.33 mL) and Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (40.0g) were stirred at 50-55°C for period of 60min. The reaction mass was cooled to room temperature and the product layer was washed with ethyl acetate (200.0mL). pH of the separated aqueous product layer was adjusted to 4.0 to 4.5 using acetic acid at 10-15°C. The obtained solid material was filtered and washed with water (lOO.OmL). This material was dried to obtain the title product.

Yield: 32.35 g, 83.37%; HPLC Purity: 99.45%; Desethyl impurity: 0.12%.

Example-5: Preparation of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

A mixture of 0.4N NaOH solution (791.66 mL) and Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (50.0g) were stirred at 50-55°C for period of 60min. The reaction mass was cooled to room temperature and the product layer was washed with ethyl acetate (250.0mL). pH of the separated aqueous product layer was adjusted to 3.0 to 4.0 using citric acid at 10-15°C. The obtained solid material was filtered and washed with water (125.0mL). This material was dried to obtain the title product.

Yield: 37.0 g, 76.28%; HPLC Purity: 99.69%; Desethyl impurity: 0.083%.

Example-6: Preparation of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

A mixture of 0.4N NaOH solution (395.83 mL) and Methyl 2-ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylate (25. Og) were stirred at 50-55°C for period of 60min. The reaction mass was cooled to room temperature and the product layer was washed with ethyl acetate (lOO.OmL). pH of the separated aqueous product layer was adjusted to 3.0 to 4.0

using hydrochloric acid at 10-15°C. The obtained solid material was filtered and washed with water (72.5 mL). This material was dried to obtain the title product. Yield: 20.22 g, 83.37%; HPLC Purity: 99.45%; Desethyl impurity: 0.217%.

Example-7: Purification of 2-Ethoxy-l-[[2′-(2,5-dihydro-5-oxo-l,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (Azilsartan)

Charged 2-Ethoxy- 1 – [[2′ -(2,5-dihydro-5-oxo- 1 ,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]benzimidazole-7-carboxylic acid (lOO.Og), methanol (600.0ml) and methylene dichloride (600.0ml) and were stirred for 10 min at 25-30°C to get a clear solution. Above solution was treated with Activated carbon (lO.Og) and stirred for 10.0 min at 25-30°C. Reaction mixture was passed through a hyflow bed and washed with a mixture of (1: 1) ratio of 200.0ml methanol and methylene dichloride. The solvent mixture was distilled out at below 50°C till the solid formation was observed. Reaction mixture is stirred for 30.0min at 30°C, then the solid was filtered and washed with 200.0ml of methylene dichloride. To the obtained solid, methanol (450.0 ml) was charged at 25-30°C, heated to 45°C, stirred for 30 min at 45°C and then cooled to 30°C. After cooling, the solid was filtered and washed with methanol (90.0ml) which was further dried at 50-55°C for 12 hours.

Yield: 80.0 g, 80.0%; HPLC Purity: 99.96%; Desethyl impurity : 0.012%.

Smilax Managing Director, S. Murali Krishna received the award from Hon’ble Chief Minister of Andhra Pradesh Shri. N. Kiran Kumar Reddy.

WO 2016147197, DAPAGLIFLOZIN, NEW PATENT, HARMAN FINOCHEM LIMITED

LINK>>> (WO2016147197) A NOVEL PROCESS FOR PREPARING (2S,3R,4R,5S,6R)-2-[4-CHLORO-3-(4-ETHOXYBENZYL)PHENY 1] -6-(HY DROXY METHYL)TETRAHYDRO-2H-PY RAN-3,4,5-TRIOL AND ITS AMORPHOUS FORM

HARMAN FINOCHEM LIMITED [IN/IN]; 107, Vinay Bhavya Complex 159-A, C.S.T. Road Kalina, Mumbai 400098 Maharashtra (IN)

KADAM, Vijay Trimbak; (IN).
SAIKRISHNA; (IN).
CHOUDHARE, Tukaram Sarjerao; (IN).
MINHAS, Harpreet Singh; (IN).
MINHAS, Gurpreet Singh; (IN)

CHAIRMAN

(2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol is sodium dependent glucose transporter (SGLT) which is currently under investigation for the treatment of type-2 diabetes. (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol is marketed under the tradename Farxiga or Forxiga.

(2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol is also known as D-glucitol, l,5-anhydro-l-C-[4-chloro-3-[(4ethoxyphenyl)methyl]phenyl]-, (I S). (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3, 4,5 -triol is a white to off-white powder with a molecular formula of C2iH2₅C10₆ and a molecular weight of 408.87

Formula-I

US 6,515,117 B2 discloses (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol and its pharmaceutically acceptable salts. US 6,515,117 B2 also describes process for preparation of (2S,3R,4R,5S,6R)-2-[4- chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol which comprises reaction of 5-bromo-2-chloro-4′-ethoxydiphenylmethane with 2,3,4,6-tetra-O-trimethylsilyl- -D-glucolactone in presence of THF/Toluene, methansulfonic acid to yield o-methylglucoside product which further reacts with Et₃SiH, BF₃Et₂0 in presence of MDC and acetonitrile to yield yellow solidified foam which is dissolved in MDC, pyridine and followed by acetylation with acetic anhydride, DMAP to yield tetra acetylated- β-C-glucoside as a white solid which is further deprotected with LiOH H₂0 in presence of THF/MeOH/H₂0 to get (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

The drawback of said prior art is having multiple process steps which makes the process very lengthy and tedious. Moreover the process discloses use of hazardous chemicals like pyridine which is not applicable to industry.

Process for preparation of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenylJ-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol is disclosed in US 7,375,213 B2 and J.Med.Chem.2008, 51, 1145-1149. The preparation process is depicted in Scheme-I.

Scheme-1

Prior art US’213 describes reaction of 2-chloro-5-bromo-4′-ethoxy-diphenylmethane with 2,3,4,6-tetra-O-trimethylsilyl-D-gluconolactone, n-BuLi in presence of THF and Heptane. After basification with TEA, the oily residue of methyl- l-C-(2-chloro-4′- ethoxy-diphenylmethan-3-yl)-a-D-glucopyranose obtained as solid compound after workup. This compound reacts with acetic anhydride in presence of THF, DIPEA and DMAP to get oily residue of methyl-2,3,4,6 tetra-0-acetyl-l-C-(2-chloro-4′-ethoxydiphenylmethan-3-yl)-a-D-glucopyranose which further undergoes reduction reaction in presence of acetonitirle, t riethylsilane, boron trifluoride etherate to yield 2,3,4,6-tetra-0-acetyl-l-C-(2-chloro-4′-ethoxydi henylmethan-3-yl)-β-D-glucopyranose which is further deprotected by reacting with LiOH monohydrate in presence of THF/MeOH/H₂0 to get (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

The said prior art describes multiple, time consuming process steps which involves getting the intermediate products as oily residue at various stages of the process, which is difficult to purify and handle for further process step. More over the workup involves multiple evaporation of product which may result in decomposition. Another drawback of the process is that the process describes n-BuLi reaction with two pot reaction. It is very difficult to transfer the material from one reactor to second reactor at -78 °C at industrial level with highly moisture sensitive reaction mass. This makes process uneconomical, cumbersome and commercially not viable. Further when practically the said method followed, a-Isomer of the final product is formed in the range of 6-8% along ith Des-bromo impurity formed in the range of 7-9 %, which increases after addition of n-butyllithium and kept the mass for overnight reaction. Moreover lactone ring cleavage is also observed in the range of 3-4% after addition of Methanesulphonic Acid/Methanol and maintained overnight for reaction completion, the removal of which is difficult from the final product.

WO 2008002824 A 1 discloses crystalline forms of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol comprising (S)-propylene glycol (PG), (R)-PG, EtOH, ethylene glycol (EG), 1 :2 L-proline, 1 : 1 L-proline, 1 : 1 L-proline hemihydrate, 1 : 1 L-phenylalanine and its preparation process.

In the light of the above drawbacks, it is necessitated to provide economical, robust, safe and commercially viable process for preparing (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

Accordingly, it is an objective of the present invention to provide a commercially viable process for the preparation of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxyb.enzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol, prepared via riovel intermediates which gives higher yield and purity and facilitates easy recovery of the final compound. The purification process does not involve any costly technique/equipment, however, carried out with solvents which are industrially feasible. More over the present invention discloses the n-BuLi insitu reaction that makes the present invention cost-effective over the teachings of prior art.

Scheme-II

Formula-Ill Formula-IV

Formula-V where R¹= allyl, prop-2-ynyl,isopropyl

Scheme-Ill

where R = allyl, prop-2-ynyl

Scheme-IV

Scheme-V

Examples:

Example-1: Preparation of 3,4,5-Tris-trimethylsiIanyloxy-6-trimethylsiIanyloxymethyl-tetrahydro-pyran-2-one

To 750 cc of dry THF added 1.12 mole 3,4,5-Trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-one at ambient temperature and stirred for 20 min. To the reaction mass added 9.0 mole N-Methyl morpholine and stirred for another 30.0 min at ambient temperature. Reaction mass was cooled to -5 °C to 0 °C and stirred for 30.0 min. Added 18.0 mole Trimethyl sillyl chloride at the temp -5 °C to 0 °C and stirred for 30.0 min. Temperature was raised to 25 °C to 30 °C and maintained for 18-20hrs. After reaction complies by GC, the reaction mass was cooled to -5 deg to 0 deg. Added Sat.Sodium bicarbonate solution to obtain the pH 7-8 and stirred for 1 hr at 0 °C. Added 500 cc toluene and stirred for lhr. Reaction mass was settled down for 30.0 min and layers were separated. To the Aqueous layer added 250 cc of toluene and stirred for 30.0 min. Layers separated and both the organic layers mixed and back washed with sat.brine solution. Organic layer was distilled under reduced pressure at a temperature of about 40 – 48 deg. Unload the oily mass . Purity: 92-96 %

Example-2: Preparation of 2-Allyloxy-2-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyI-tetrahydro-pyran-3,4,5-triol

To the mixture of 10 cc THF and 10 cc Toluene added 0.138 mole 4-(5-bromo-2-chlorobenzyl)phenyl ethyl ether at ambient temperature and stirred for 15 min. Cooled to -70 to -80°C in dry ice /acetone bath and stirred for 15 min. Added a solution of 0.014 mole n-Butyl lithium (1.9M in hexanes) at -70 to -80°C. and stirred for lhr. Added solution of 3, 4, 5-Tris-trimethylsilanyloxy-6-trimethylsilanyloxymethyl-tetrahydro-pyran-2-one in 5 cc of Toluene at -70 to -80°C and stirred for 2 to 3hrs. After the compliance of the reaction, reaction mass was quenched with Methane sulphonic acid and Allyl alcohol mixture at -70 to -80°C. Temperature was raised to ambient temperature and stirred overnight. Reaction mass was quenched with 30 cc sat.sodiumbicarbonate solution to bring the pH neutral to alkaline and stirred for 30.0 min. Layers separated and aqueous layer was extracted with 10 cc of Toluene. Organic layer was combined and washed with 30cc water and 50 cc sat. brine solution. Organic layer was distilled under reduced pressure to recover toluene. Solid compound was dissolved in 50cc of toluene and quenched in n-Hexane to obtain 83 % the compound as crystalline solid.

HPLC purity: 88 – 91 %

I R data:

Anomeric C-0 stretching: 1242 cm^“1

Allylic C- O stretching: 1 177 cm^“1

Allylic C- H stretching: 3010 – 3120 cm^“1

Aromatic C- CI stretching: 820 cm^“1

Lactones O – H stretching: 3240 – 3380 cm^“1

Lactones C – 0 stretching: 1045 – 1092 cm^“1

Aromatic C=C stretching: 1510 , 1548 , 1603 , 1703 cm^“1

Alkane C – H stretching: 2877,2866, 2956, 2958, 2962 cm^“1

Aromatic C – H stretching: 3050 – 3090 cm^“1

Dip-Mass

(M+Na) 487.19 m/z

(M+K) 503.17 m/z

Example 3: Preparation of 2-prop-2ynyl-2-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyl-tetrahydro-pyran-3,4,5-triol

To the mixture of 10 cc THF and 10 cc Toluene added 0.138 mole 4-(5-bromo-2-chlorobenzyl)phenyl ethyl ether at ambient temperature and stirred for 15 min. Cooled to -70 to -80°C in dry ice /acetone bath and stirred for 15 min. Added a solution of 0.014 mole n-Butyl lithium (1.9M in hexanes) at -70 to -80°C. and stirred for lhr. Added solution of 3, 4, 5-Tris-trimethylsilanyloxy-6-trimethylsilanyloxymethyl-tetrahydro-pyran-2-one in 5 cc of Toluene at -70 to -80°C and stirred for 2 to 3hrs. After the compliance of the reaction, the reaction mass was quenched with Methane sulphonic acid and propargyl alcohol mixture at -70 to -80°C. Temperature was raised to ambient temperature and stirred overnight. Reaction mass was quenched with 30 cc sat.sodiumbicarbonate solution to bring the pH neutral to alkaline. Reaction mass stirred for 30.0 min. Layers separated and aqueous layer was extracted with 10 cc of Toluene. Organic layer were combined and washed with 30cc water and 50 cc sat. brine solution. Organic layer was distilled under reduced pressure to recover toluene. Solid compound dissolved in 50cc of toluene and quenched in n-Hexane to obtain 75 – 80 % the compound as crystalline solid.

HPLC purity: 88 – 93 %

IR data:

Anomeric C-0 stretching: 1242 cm^“1

Propargyl ^{~c CH} stretching: 2125 cm^“1

Propargyl C- H stretching : 3010 – 3120 cm^“1

Aromatic C- CI stretching: 820 cm^“1

Lactones O – H stretching: 3240 – 3380 cm^“1

Lactones C – 0 stretching: 1045 – 1092 cm^“1

Aromatic C=C stretching: 1510 , 1548 , 1603 , 1703 cm^“1

Alkane C – H stretching: 2877, 2866,2956,2958,2962 cm^“1

Aromatic C – H stretching: 3050 – 3090 cm^“1

Dip-Mass

(M+Na) 485.25 m/z

(M+K) 501.25 m/z

Example-4: Preparation of 2-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyI-tetrahydro-pyran-3,4,5-trioI

To the mixture of 20 cc (1 : 1 MDC + ACN) added 0.1 1 mole 2-Allyloxy-2-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyl-tetrahydro-pyran-3,4,5-triol under argon atmosphere, and stirred the reaction mass for 30.0 min. Cooled the reaction mass to -40 to -55°C in a dry ice/acetone bath under argon atmosphere. Charged 3 mole Triethylsilane at -40 to -55°C and stirred the reaction mass for 30.0 min at -50 to -55°C. Slowly added Borontrifloride in diethyl ether solution at -40 to -55°C and stirred the reaction mass for 2 hrs. Quenched the reaction mass with 50 cc sat. sodium bicarbonate solution at -40 to -55°C . and stirred the reaction mass for 30.0 min. Slowly raised the temperature to 25 to 30°C. Settled down the reaction mass and separated the layers, extracted the aqueous layer with 100 cc of MDC. Combined the organic layer and wash with 500 cc water. Washed the organic layer with 500 cc of sat. Brine solution. Distilled out the MDC under reduced pressure below 40°C. to get 85 %the light yellow solid.

HPLC purity: 92-95 %

Example 5: Preparation of 2-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyl-tetrahydro-pyran-3,4,5-triol

To the mixture of 20 cc (1 :1 MDC + ACN) added 0.11 mole 2-prop-2-ynyl-2-[4-Chloro-3-(4-ethoxy-benzyl)-phenyl]-6-hydroxymethyl-tetrahydro-pyran-3,4,5-triol under argon

atmosphere. Stirred the reaction mass for 30.0 min. Cooled the reaction mass to -40 to -55°C in a dry ice/acetone bath under argon atmosphere. Charged 3 mole Triethylsilane at -40 to -55°C and stirred the reaction mass for 30.0 min at -50 to -55°C. Slowly added Borontrifloride in diethyl ether solution at -40 to -55°C and stirred the reaction mass for 2 hrs. Quenched the reaction mass with 50 cc sat. sodium bicarbonate solution at -40 to -55°C and Stirred the reaction mass for 30.0 min. Slowly raised the temperature to 25 to 30°C. Settled down the reaction mass and separated the layers, extracted the aqueous layer with 100 cc of MDC. Combined the organic layer and washed with 500 cc water. Washed the organic layer with 500 cc of sat. Brine solution. Distilled out the MDC under reduced pressure below 40°C. to get 85%the light yellow solid.

HPLC purity: 90%

Example 6: Preparation of amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol

To the solid obtained from example 4 charged 500cc of n-heptane and stirred for ½hrs at ambient temperature. Heated the reaction mass to 55-60°C and stirred it for 2-3 hrs.; cooled to room temperature and maintained for 4-5 hrs. Filtered the solid and washed the, cake with 100 cc n-heptane. Dried at 40-45°C under vacuum to get 85% amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

HPLC purity: 91-93%

Example 7: Preparation of amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol

To the solid obtained from example 5 charged 500cc of n-heptane and stirred for ½ hrs at ambient temperature. Heated the reaction mass to 55-60°C and stirred it for 2-3 hrs., cooled to room temperature and maintained for 4-5 hrs. Filtered the solid and washed the cake with 100 cc n-heptane. Dried at 40-45 °C under vacuum to get 85-88% amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6- (hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol.

HPLC purity: 89-91%

Example 8: Preparation of L-proline – (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyI]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol co crystal

To the 10 cc of Ethyl acetate charged 1.0 mole (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol under argon atmosphere at ambient temperature and stirred for 30.0 min to get clear solution. Slowly heated the reaction mass to 60 – 65°C and stirred for 1 hr. Slowly added L-proline at 60 -65°C and maintained for 1 hr. Slowly added 15 cc n-Heptane to the reaction mass at 60 -65°C and stirred the mass for 2.5 hrs. Cooled the mass to ambient temperature for 3-4 hrs and maintained for 5 hrs. Filtered the mass under argon atmosphere. Washed the cake with 10 cc n-Heptane. Dried the cake at 50-55°C under reduced pressure to get 92% titled compound.

HPLC purity: 99%

Example 9: Preparation of L-proline – (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triolco crystal

To the 10 cc of acetone charged 1.0 mole (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol under argon atmosphere at ambient temperature and stirred for 30.0 min to get clear solution. Slowly heated the reaction mass to 60 – 65°C and stirred for 1 hr. Slowly added^“ proline at 60 -65°C and maintained for 1 hr. Slowly added 15 cc n-Heptane to the reaction mass at 60 -65°C and stirred the mass for 2.5 hrs. Cooled the mass to ambient temperature for 3-4 hrs and maintained for 5 hrs. Filtered the mass under argon atmosphere. Washed the cake with 10 cc n-Heptane. Dried the cake at 50-55°C under reduced pressure to get 93-95% titled compound.

HPLC purity: 98-99%

Example 10: Preparation of amorphous form of (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol

To the 15 cc ethyl acetate added (2S,3R,4R,5S,6R)-2-[4-chloro-3-(4-ethoxybenzyl)phenyl]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol at ambient temperature and stirred for 30.0 min. Slowly added 5- 8 cc sat. sodium bicarbonate solution at ambient temperature and stirred for 1.5 hr to get the clear solution. Settled down and separated layers. Extracted the aqueous layer with 25 cc ethyl acetate.

Combined the organic layers and washed the ethyl acetate layer with 50 cc sat. Sodium chloride solution. Distilled out ethyl acetate under reduced pressure at 40 – 45°C to get ^■fluffy solid. Charged 50 cc n-Heptane and stirred for 5 hrs to get 70-78% the title compound as Amorphous soild.

HPLC purity: 99.8-99.95 %

Example 11: Preparation of 2-chloro -4′- ethoxydiphenylmethane (impurity)

To the 20 cc THF and 20 cc Toluene added 0.25 mole 2-ehloro-5-bromo-4′- ethoxydiphenylmethane under argon atmosphere. Cooled the reaction mass to – 78° C. Slowly added n-Butyl lithium (1.9 M in hexane) at – 78° C and stirred for 30 min. Slowly added 20 % Ammonium chloride solution to the reaction mass. Brought the reaction mass to ambient temperature and stirred for 30 min. Settled and separated layers. Extracted the aqueous layer with 50 cc toluene. Washed the combined organic layer with 500 cc brine solution. Distilled out the toluene and charged heptanes, stirred for 2 – 3 hrs at ambient temperature. Filtered the product and dried the product at 45 – 50°C under reduced pressure to get 93 % titled compound.

Mass: (m+1) 247 m/z found 247.1 1

HPLC purity: 96.33 %

SHENDRA AURANGABAD, MAHARASHTRA, INDIA

Bhupinder Singh Manhas

////////WO 2016147197, DAPAGLIFLOZIN, NEW PATENT, HARMAN FINOCHEM LIMITED

VT 1129

• Originator Viamet Pharmaceuticals
• Class Antifungals; Small molecules
• Mechanism of Action 14-alpha demethylase inhibitors

• Orphan Drug Status Yes – Cryptococcosis
• On Fast track Cryptococcosis
• Phase I Cryptococcosis

• Most Recent Events

  • 01 Jun 2016 VT 1129 receives Fast Track designation for Cryptococcosis [PO] (In volunteers) in USA
  • 30 May 2016 Viamet Pharmaceuticals plans a phase II trial for Cryptococcal meningitis in USA (Viamet Pharmaceuticals pipeline; May 2016)
  • 27 May 2016 Phase-I clinical trials in Cryptococcosis (In volunteers) in USA (PO) before May 2016 (Viamet Pharmaceuticals pipeline; May 2016)

Viamet, in collaboration with Therapeutics for Rare and Neglected diseases, is investigating VT-1129, a small-molecule lanosterol demethylase inhibitor, developed using the company’s Metallophile technology, for treating fungal infections, including Cryptococcus neoformans meningitis.

VT-1129 is a novel oral agent that we are developing for the treatment of cryptococcal meningitis, a life-threatening fungal infection of the brain and the spinal cord that occurs most frequently in patients with HIV infection, transplant recipients and oncology patients. Without treatment, the disease is almost always fatal.

VT-1129 has shown high potency and selectivity in in vitro studies and is an orally administered inhibitor of fungal CYP51, ametalloenzyme important in fungal cell wall synthesis. In preclinical studies, VT-1129 has demonstrated substantial potency against Cryptococcus species, the fungal pathogens that cause cryptoccocal meningitis, and has also been shown to accumulate to high concentrations within the central nervous system, the primary site of infection.

In in vitro studies, VT-1129 was significantly more potent against Cryptococcus isolates than fluconazole, which is commonly used for maintenance therapy of cryptococcal meningitis in the United States and as a primary therapy in the developing world. Oral VT-1129 has also been studied in a preclinical model of cryptococcal meningitis, where it was compared to fluconazole.  At the conclusion of the study, there was no detectable evidence of Cryptococcus in the brain tissue of the high dose VT-1129 treated groups, in contrast to those groups treated with fluconazole. To our knowledge, this ability to reduce the Cryptococcus pathogen in the central nervous system to undetectable levels in this preclinical model is unique to VT-1129.

Opportunity

An estimated 3,400 hospitalizations related to cryptococcal meningitis occur annually in the United States and the FDA has granted orphan drug designation to VT-1129 for the treatment of this life-threatening disease. In addition, the FDA has granted Qualified Infectious Disease Product designation to VT-1129 for the treatment of Cryptococcus infections, which further underscores the unmet medical need. In developing regions such as Africa, cryptococcal meningitis is a major public health problem, with approximately one million cases and mortality rates estimated to be as high as 55-70%.

Current Status

VT-1129 has received orphan drug and Fast Track designations for the treatment of cryptococcal meningitis and has been designated a Qualified Infectious Disease Product (QIDP) by the U.S. Fod and Drug Administration.  We are currently conducting a Phase 1 single-ascending dose study of VT-1129 in healthy volunteers.

• Activity of VT-1129 against Cryptococcus neoformans Clinical Isolates with High Fluconazole MICs
• VT1129 Binds Potently and Selectively to Recombinant Cryptococcal CYP51 Consistent with Its In Vitro Anti-Cryptococcal Activity (ICAAC 2015)
• Investigational CYP51 Inhibitors VT-1161 and VT-1129 Show Strong In Vitro Activity Against Candida glabrata Isolates Clinically Resistant to Azole and Echinocandin Compounds (ICAAC 2015)
• The Novel Fungal Cyp51 Inhibitor VT-1129 Demonstrates Potent In Vivo Activity In Mice Against Cryptococcal Meningitis with a Loading/Maintenance Dose Strategy (ECCMID 2015)
• Susceptibility testing of VT-1129, a novel fungal CYP51 inhibitor, against Cryptococcus neoformans and Cryptococcus gattii (ICCC 2014)
• The Novel Fungal Cyp51 Inhibitor VT-1129 Demonstrates Potent In vivo Activity Against Cryptococcal Meningitis with an Improved Formulation (ICCC 2014)
• The Fungal Cyp51 Inhibitors VT-1161 and VT-1129 Maintain in vitro Activity Against Candida albicans Isolates with Reduced Antifungal Susceptibility (2011 ICAAC)
• In Vitro Activity of Two Metalloenzyme Inhibitors Compared to Caspofungin and Fluconazole Against a Panel of 74 Candida spp. (2010 ICAAC)
• Novel Metalloenzyme Inhibitors, VT-1161 and VT-1129, Exhibit Efficacy and Survival Benefit in a Murine Systemic Candidiasis Model (2010 ICAAC)

Conclusions

• VT-1129 has robust activity against Cryptococcus isolates with elevated fluconazole MICs and may be a viable option in persons infected with such strains.

• A Phase 1 study of VT-1129 in healthy volunteers is scheduled to begin by the end of 2015. Phase 2 trials in persons with cryptococcal meningitis are targeted to begin by the end of 2016.

Living organisms have developed tightly regulated processes that specifically import metals, transport them to intracellular storage sites and ultimately transport them to sites of use. One of the most important functions of metals such as zinc and iron in biological systems is to enable the activity of metalloenzymes. Metalloenzymes are enzymes that incorporate metal ions into the enzyme active site and utilize the metal as a part of the catalytic process. More than one-third of all characterized enzymes are metalloenzymes.

The function of metalloenzymes is highly dependent on the presence of the metal ion in the active site of the enzyme. It is well recognized that agents which bind to and inactivate the active site metal ion dramatically decrease the activity of the enzyme. Nature employs this same strategy to decrease the activity of certain metalloenzymes during periods in which the enzymatic activity is undesirable. For example, the protein TIMP (tissue inhibitor of metalloproteases) binds to the zinc ion in the active site of various matrix metalloprotease enzymes and thereby arrests the enzymatic activity. The pharmaceutical industry has used the same strategy in the design of therapeutic agents. For example, the azole antifungal agents fluconazole and voriconazole contain a l-(l,2,4-triazole) group that binds to the heme iron present in the active site of the target enzyme lanosterol demethylase and thereby inactivates the enzyme.

In the design of clinically safe and effective metalloenzyme inhibitors, use of the most appropriate metal-binding group for the particular target and clinical indication is critical. If a weakly binding metal-binding group is utilized, potency may be suboptimal. On the other

hand, if a very tightly binding metal-binding group is utilized, selectivity for the target enzyme versus related metalloenzymes may be suboptimal. The lack of optimal selectivity can be a cause for clinical toxicity due to unintended inhibition of these off-target metalloenzymes. One example of such clinical toxicity is the unintended inhibition of human drug metabolizing enzymes such as CYP2C9, CYP2C19 and CYP3A4 by the currently- available azole antifungal agents such as fluconazole and voriconazole. It is believed that this off-target inhibition is caused primarily by the indiscriminate binding of the currently utilized l-(l,2,4-triazole) to iron in the active site of CYP2C9, CYP2C19 and CYP3A4. Another example of this is the joint pain that has been observed in many clinical trials of matrix metalloproteinase inhibitors. This toxicity is considered to be related to inhibition of off-target metalloenzymes due to indiscriminate binding of the hydroxamic acid group to zinc in the off-target active sites.

Therefore, the search for metal-binding groups that can achieve a better balance of potency and selectivity remains an important goal and would be significant in the realization of therapeutic agents and methods to address currently unmet needs in treating and preventing diseases, disorders and symptoms thereof. Similarly, methods of synthesizing such therapeutic agents on the laboratory and, ultimately, commercial scale is needed. Addition of metal-based nucleophiles (Zn, Zr, Ce, Ti, Mg, Mn, Li) to azole-methyl substituted ketones have been effected in the synthesis of voriconazole (M. Butters, Org. Process Res. Dev.2001, 5, 28-36). The nucleophile in these examples was an ethyl-pyrimidine substrate. Similarly, optically active azole-methyl epoxide has been prepared as precursor electrophile toward the synthesis of ravuconazole (A. Tsuruoka, Chem. Pharm. Bull.1998, 46, 623-630). Despite this, the development of methodology with improved efficiency and selectivity is desirable.

PATENT

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2011133875

Scheme 1

EXAMPLE 7

2-(2, 4-Difluorophenyl)-l, l-difluoro-3-(lH-tetrazol-l-yl)-l-(5-(4- (trifluoromethoxy) phenyl) pyridin-2-yl) propan-2-ol (7)

To a stirred solution of bromo epoxide C (0.5 g, 1.38 mmol) in THF (30 mL) and water (14 mL) were added 4-(trifluoromethoxy) phenylboronic acid (0.22 g, 1.1 mmol), Na₂C0₃ (0.32 g, 3.1 mmol) and Pd(dppf)₂Cl₂ (0.28 g, 0.34 mmol) at RT under inert atmosphere. After purged with argon for a period of 30 min, the reaction mixture was heated to 75°C and stirring was continued for 4 h. Progress of the reaction was monitored by TLC. The reaction mixture was cooled to RT and filtered through a pad of celite. The filtrate was concentrated under reduced pressure; obtained residue was dissolved in ethyl acetate (30 mL). The organic layer was washed with water, brine and dried over anhydrous Na₂S0₄ and concentrated under reduced pressure. The crude compound was purified by column chromatography to afford the coupled product (0.45 g, 1.0 mmol, 73%) as solid. 1H NMR (200 MHz, CDC1₃): δ 8.87 (s, 1 H), 7.90 (dd, / = 8.2, 2.2 Hz, 1 H), 7.66-7.54 (m, 3 H), 7.49-7.34 (m, 3 H), 6.90-6.70 (m, 2 H), 3.49 (d, / = 5.0 Hz, 1 H), 3.02-2.95 (m, 1 H). Mass: m/z 444 [M⁺+l].

To a stirred solution of the coupled product (0.45 g, 1.0 mmol) in DMF (10 mL) was added K₂C0₃ (70 mg, 0.5 mmol) followed by IH-tetrazole (70 mg, 1.0 mmol) at RT under inert atmosphere. The reaction mixture was stirred for 4 h at 80 °C. The volatiles were removed under reduced pressure and obtained residue was dissolved in water (15 mL) and extracted with ethyl acetate (2 x 20 mL). The combined organic layers were washed with water, brine and dried over anhydrous Na₂S0₄ and concentrated under reduced pressure. The crude compound was purified by column chromatography to afford 7 (0.19 g, 0.37 mmol, 36 %) as white solid. 1H NMR (500 MHz, CDC1₃): δ 8.76 (s, 1 H), 8.70 (s, 1 H), 7.97 (dd, / = 8.0, 2.0 Hz, 1 H), 7.68 (d, / = 8.5 Hz, 1 H), 7.60-7.56 (m, 3 H), 7.43-7.36 (m, 3 H), 6.80-6.76 (m, 1 H), 6.70-6.67 (m, 1 H), 5.57 (d, / = 14.5 Hz, 1 H), 5.17 (d, / = 14.5 Hz, 1 H). HPLC: 98.3%. Mass: m/z 513.9 [M⁺+l].

Chiral preparative HPLC of enantiomers:

The enantiomers of 7 (17.8 g, 34.6 mmol) were separated by normal-phase preparative high performance liquid chromatography (Chiralpak AD-H, 250 x 21.2 mm, 5μ; using (A) n-hexane – (B) IPA (A:B : 70:30) as a mobile phase; Flow rate: 15 mL/min) to obtain 7(+) (6.0 g) and 7(-) (5.8 g).

Analytical data for 7 (+):

HPLC: 99.8%.

Chiral HPLC: R_t = 9.88 min (Chiralpak AD-H, 250 x 4.6mm, 5μ; mobile phase (A) n-Hexane (B) IPA (7/3): A: B (70:30); flow Rate: 1.00 mL/min)

Optical rotation [a]_D²⁵: + 19° (C = 0.1 % in MeOH).

Patent

WO2015143137,

https://patentscope.wipo.int/search/ko/detail.jsf;jsessionid=61AAA66F887FDBB9CFC3F752AFF04016.wapp2nC?docId=WO2015143137&recNum=303&office=&queryString=&prevFilter=%26fq%3DICF_M%3A%22C07D%22&sortOption=%EA%B3%B5%EA%B0%9C%EC%9D%BC(%EB%82%B4%EB%A6%BC%EC%B0%A8%EC%88%9C)&maxRec=58609

Examples

The present invention will now be demonstrated using specific examples that are not to be construed as limiting.

General Experimental Procedures

Definitions of variables in the structures in schemes herein are commensurate with those of corresponding positions in the formulae delineated herein.

Synthesis of 1 or la

A process to prepare enantiopure compound 1 or la is disclosed. Syntheses of 1 or la may be accomplished using the example syntheses that are shown below (Schemes 1-9). The preparation of precursor ketone 8 is performed starting with reaction of dibromo-pyridine 2-Br with ethyl 2-bromo-difluoroacetate to produce ester 3-Br. This ester is reacted with tetrazole reagent 4 via Claisen reaction to furnish 5-Br. Decarboxylation of 5-Br via a two-step process produces compound 6-Br. Suzukin coupling of 6-Br with boronate 7 furnishes 8.

Scheme 1. Synthesis of ketone 8

Ketone 8 may be prepared in an analogous fashion as described in Scheme 1 starting from corresponding substituted 2-bromo-pyridines, which can be prepared using according to synthetic transformations known in the art and contained in the references cited herein (Scheme 2).

Scheme 2. Synthesis of ketone 8

= halo, -0(C=0)-alkyl, -0(C=0)-substituted alkyl, -0(C=0)-aryl, -0(C=0)-substituted aryl, -0(C=0)-0-alkyl, – 0(C=0)-0-substituted alkyl, -0(C=0)-0-aryl, -0(C=0)-0-substituted aryl, -0(S0₂)-alkyl, -0(S0₂)-substituted alkyl, – 0(S0₂)-aryl, or -0(S0₂)-substituted aryl.

Compounds 6 or 8 may be reacted with a series of metallated derivatives of 2,4-difluoro-bromobenzene and chiral catalysts/reagents (e.g. BINOL) to effect enantiofacial-selective addition to the carbonyl group of 6 or 8 (Scheme 3). These additions can be performed on 6 or 8 to furnish 9 (or 9a, the enantiomer of 9, or mixtures thereof) or 1 (or la, the enantiomer of 1, or mixtures thereof), respectively.

Scheme 3. Synthesis of 1 or la

R-i = halo, -0(C=0)-alkyl, -0(C=0)-substituted alkyl, -0(C=0)-aryl, -0(C=0)-substituted aryl, -0(C=0)-0-alkyl, -0(C=0)-0-substituted alkyl, -0(C=0)-0-aryl, -0(C=0)-0-substituted aryl, -0(S0₂)-alkyl, -0(S0₂)-substituted alkyl, -0(S0₂)-aryl, or -0(S0₂)-substituted aryl.

Alternatively, ketone 8 can be synthesized from aldehyde 10 (Scheme 4). Aldehyde 10 is coupled with 7 to produce 11. Compound 11 is then converted to 12 via treatment with diethylaminosulfurtrifluoride (DAST).

Scheme 4. Alternate synthesis of ketone 8

Scheme 5 outlines the synthesis of precursor ketone 15-Br. The ketone is prepared by conversion of 2-Br to 3-Br as described above. Next, ester 3-Br is converted to 15-Br by treatment via lithiation of 2,4-difluoro-bromobenzene.

Scheme 5. Synthesis of ketone 15-Br

Ketone 15 may be prepared in an analogous fashion as described for 15-Br in Scheme 5 starting from corresponding substituted 2-bromo-pyridines, which can be prepared using according to synthetic transformations known in the art and contained in the references cited herein (Scheme 6).

Scheme 6. Synthesis of ketone 15

F = halo, -0(C=0)-alkyl, -0(C=0)-substituted alkyl, -0(C=0)-aryl, -0(C=0)-substituted aryl, -0(C=0)-0-alkyl, – 0(C=0)-0-substituted alkyl, -0(C=0)-0-aryl, -0(C=0)-0-substituted aryl, -0(S0₂)-alkyl, -0(S0₂)-substituted alkyl, – 0(S0₂)-aryl, or -0(S0₂)-substituted aryl.

Ketone 15 may be used to prepare 9 (or 9a, the enantiomer of 9, or mixtures thereof) or 1 (or la, the enantiomer of 1, or mixtures thereof) by the following three-step process (Scheme 7). In the presence of a chiral catalyst/reagent (e.g. proline derivatives), base-treated nitromethane is added to 15 or 16 to furnish 17 (or 17a, the enantiomer of 17, or mixtures thereof) or 18 (or 18a, the enantiomer of 18, or mixtures thereof), respectively. Reduction of 17 (or 17a, the enantiomer of 17, or mixtures thereof) or 18 (or 18a, the enantiomer of 18, or mixtures thereof) (e.g. lithium aluminum hydride) produces 19 (or 19a, the enantiomer of 19, or mixtures thereof) or 20 (or 20a, the enantiomer of 20, or mixtures thereof). Annulation of 19 (or 19a, the enantiomer of 19, or mixtures thereof) or 20 (or 20a, the enantiomer of 20, or mixtures thereof) by treatment with sodium azide/triethylorthoformate furnishes tetrazoles 9 (or 9a, the enantiomer of 9, or mixtures thereof) or 1 (or la, the enantiomer of 1, or mixtures thereof). Suzuki coupling of 9 (or 9a, the enantiomer of 9, or mixtures thereof) with 4-trifluoromethoxyphenyl-boronic acid produces 1 (or la, the enantiomer of 1, or mixtures thereof).

Scheme 7. Asymmetric Henry reaction

R-ι = halo, -0(C=0)-alkyl, -0(C=0)-substituted alkyl, -0(C=0)-aryl, -0(C=0)-substituted aryl, -0(C=0)-0-alkyl, 0(C=0)-0-substituted alkyl, -0(C=0)-0-aryl, -0(C=0)-0-substituted aryl, -0(S0₂)-alkyl, -0(S0₂)-substituted a 0(S0₂)-aryl, or -0(S0₂)-substituted aryl.

Ketone 21 may be employed to prepare optically-active epoxides via Horner-Emmons reaction of a difluoromethyl substrate to produce 22 or 22a. Ketones related to 21 have been prepared (M. Butters, Org. Process Res. Dev. 2001, 5, 28-36). Nucleophilic addition of metalated 5-(4-trifluoromethoxy)phenyl-2-pyridine (M = metal) to epoxide 22 or 22a may furnish compound

1 or la.

Scheme 8. Enantioselective epoxidation strategy

Ketone 15 or 16 may be used to prepare 9 (or 9a, the enantiomer of 9, or mixtures thereof) or 1 (or la, the enantiomer of 1, or mixtures thereof) by an alternative three-step process to Scheme 7 (Scheme 9). In the presence of a chiral catalyst/reagent, trimethylsilyl-cyanide is added to 15 or 16 to furnish 23 (or 23a, the enantiomer of 23, or mixtures thereof) or 24 (or 24a, the enantiomer of 24, or mixtures thereof), respectively (S.M. Dankwardt, Tetrahedron Lett. 1998, 39, 4971-4974). Reduction of 23 (or 23a, the enantiomer of 23, or mixtures thereof) or 24 (or 24a, the enantiomer of 24, or mixtures thereof) (e.g. lithium aluminum hydride) produces 19 (or 19a, the enantiomer of 19, or mixtures thereof) or 20 (or 20a, the enantiomer of 20, or mixtures thereof). Annulation of 19 (or 19a, the enantiomer of 19, or mixtures thereof) or 20 (or 20a, the enantiomer of 20, or mixtures thereof) by treatment with sodium azide/triethylorthoformate furnishes tetrazoles 9 (or 9a, the enantiomer of 9, or mixtures thereof) or 1 (or la, the enantiomer of 1, or mixtures thereof). Suzuki coupling of 9 (or 9a, the enantiomer of 9, or mixtures thereof) with 4-trifluoromethoxyphenyl-boronic acid produces 1 (or la, the enantiomer of 1, or mixtures thereof).

Scheme 9. Asymmetric cyanohydrin strategy

R’ = H or trimethylsilyl

Suzuki

R-i = halo, -0(C=0)-alkyl, -0(C=0)-substituted alkyl, -0(C=0)-aryl, -0(C=0)-substituted aryl, -0(C=0)-0-alkyl, -0(C=0)-0-substituted alkyl, -0(C=0)-0-aryl, -0(C=0)-0-substituted aryl, -0(S0₂)-alkyl, -0(S0₂)-substituted alkyl, -0(S0₂)-aryl, or -0(S0₂)-substituted aryl.

1

2-(2, 4-Difluorophenyl)-l, l-difluoro-3-(lH-tetrazol-l-yl)-l-(5-(4-(trifluoromethoxy) phenyl) pyridin-2-yl) propan-2-ol (1 or la)

White powder: *H NMR (500 MHz, CDC1₃): δ 8.76 (s, 1 H), 8.70 (s, 1 H), 7.97 (dd, J = 8.0, 2.0 Hz, 1 H), 7.68 (d, / = 8.5 Hz, 1 H), 7.60-7.56 (m, 3 H), 7.43-7.36 (m, 3 H), 6.80-6.76 (m, 1 H), 6.70-6.67 (m, 1 H), 5.57 (d, J = 14.5 Hz, 1 H), 5.17 (d, J = 14.5 Hz, 1 H). HPLC: 98.3%. Mass: m/z 513.9 [M⁺+l]. HPLC: 99.8%. Optical rotation [a]_D²⁵: + 19° (C = 0.1 % in MeOH).

INTERMEDIATE 3-Br Ri = Br)

To a clean and dry 100 L jacketed reactor was added copper powder (1375 g, 2.05 equiv, 10 micron, sphereoidal, SAFC Cat # 326453) and DMSO (17.5 L, 7 vol). Next, ethyl bromodifluoroacetate (2.25 kg, 1.05 equiv, Apollo lot # 102956) was added and the resulting slurry stirred at 20-25 °C for 1-2 hours. Then 2,5-dibromopyridine (2-Br, 2.5 kg, 1.0 equiv, Alfa Aesar lot # F14P38) was added to the batch and the mixture was immediately heated (using the glycol jacket) to 35 °C. After 70 hours at 35 °C, the mixture was sampled for CG/MS analysis. A sample of the reaction slurry was diluted with 1/1 CH₃CN/water, filtered (0.45 micron), and the filtrate analyzed directly. Ideally, the reaction is deemed complete if <5% (AUC) of 2,5-dibromopyridine remains. In this particular batch, 10% (AUC) of 2,5-dibromopyridine remained. However due to the already lengthy reaction time, we felt that prolonging the batch would not help the conversion any further. The reaction was then deemed complete and diluted with EtOAc (35 L). The reaction mixture was stirred at 20-35 °C for 1 hour and then the solids (copper salts) were removed by filtration through a pad of Celite. The residual solids inside the reactor were rinsed forward using EtOAc (2 x 10 L) and then this was filtered through the Celite. The filter cake was washed with additional EtOAc (3 x 10 L) and the EtOAc filtrates were combined. A buffer solution was prepared by dissolving NH₄CI (10 kg) in DI water (100 L), followed by the addition of aqueous 28% NH₄OH (2.0 L) to reach pH = 9. Then the combined EtOAc filtrates were added slowly to a pre-cooled (0 to 15 °C) solution of NH₄C1 and NH₄OH (35 L, pH = 9) buffer while maintaining T<30 °C. The mixture was then stirred for 15-30 minutes and the phases were allowed to separate. The aqueous layer (blue in color) was removed and the organic layer was washed with the buffer solution until no blue color was discernable in the aqueous layer. This experiment required 3 x 17.5 L washes. The organic layer was then washed with a 1/1 mixture of Brine (12.5 L) and the pH = 9 NH₄C1 buffer solution (12.5 L), dried over MgS0₄, filtered, and concentrated to dryness. This provided crude compound 3-Br [2.29 kg, 77% yield, 88% (AUC) by GC/MS] as a yellow oil. The major impurity present in crude 3-Br was unreacted 2,5-dibromopyridine [10% (AUC) by GC/MS]. ‘ll NMR (CDC1₃) was consistent with previous lots of crude compound 3-Br. Crude compound 3-Br was then combined with similar purity lots and purified by column chromatography (5/95 EtO Ac/heptane on S1O₂ gel).

INTERMEDIATE 15-Br (R, = Br)

To a clean and dry 72 L round bottom flask was added l-bromo-2,4-difluorobenzene (1586 g,

1.15 equiv, Oakwood lot # H4460) and MTBE (20 L, 12.6 vol). This solution was cooled to -70 to -75 °C and treated with n-BuLi (3286 mL, 1.15 equiv, 2.5 M in hexanes, SAFC lot # 32799MJ), added as rapidly as possible while maintaining -75 to -55 °C. This addition typically required 35-45 minutes to complete. (NOTE: If the n-BuLi is added slowly, an white slurry will form and this typically gives poor results). After stirring at -70 to -65 °C for 45 minutes, a solution of compound 3-Br (2000 g, 1.0 equiv, AMRI lot # 15CL049A) in MTBE (3 vol) was added rapidly (20-30 min) by addition funnel to the aryl lithium solution while maintaining -75 to -55 °C. After stirring for 30-60 minutes at -75 to -55 °C, the reaction was analyzed by GC/MS and showed only trace (0.5% AUC) l-bromo-2,4-difluorobenzene present. The reaction was slowly quenched with aqueous 2 M HC1 (3.6 L) and allowed to warm to room temperature. The mixture was adjusted to pH = 6.5 to 8.5 using NaHCC>3 (4 L), and the organic layer was separated. The MTBE layer was washed with brine (5% NaCl in water, 4 L), dried over MgS0₄, filtered, and concentrated. In order to convert the intermediate hemi-acetal to 4-Br, the crude mixture was heated inside the 20 L rotovap flask at 60-65 °C for 3 hours (under vacuum), at this point all the hemi-acetal was converted to the desired ketone 4 by ^!Η NMR (CDC1₃). This provided crude compound 4-Br [2.36 kg, 75% (AUC) by HPLC] as a brown oil that solidified upon standing. This material can then be used “as-is” in the next step without further purification.

PATENT FOR VT1161    SIMILAR TO VT 1129

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2016149486&recNum=1&maxRec=&office=&prevFilter=&sortOption=&queryString=&tab=PCTDescription

Synthesis of 1 or la

EXAMPLE 1

Preparation of Compound 1 X-Hydrate

Compound 1 and its preparation are described in the art, including in US Patent 8,236,962 (incorporated by reference herein). Compound 1 can then be partitioned between ethanol and water to afford Compound 1 X-hydrate.

EXAMPLE 2

Compound 1 Anhydrous Form Recrystallization

Compound 1 X-hydrate (29.1 g, 28.0 g contained 1) was suspended in 2-propanol (150 ml) and heated to 56 °C. The solution was filtered through a 0.45 μιη Nylon membrane with 2-propanol rinses. The combined filtrate was concentrated to 96.5 g of a light amber solution. The solution was transferred to a 1-L flask equipped with overhead stirring, thermocouple and addition funnel, using 2-propanol (30 ml total) to complete the transfer. The combined solution contained about 116 ml 2-propanol.

The solution was heated to 50 °C and n-heptane (234 ml) was added over 22 minutes. The resulting hazy mixture was seeded with 1 anhydrous form. After about 1 hour a good

suspension had formed. Additional n-heptane (230 ml) was added over 48 minutes. Some granular material separated but most of the suspension was a finely divided pale beige solid. After about ½ hour at 50 °C the suspension was cooled at 10 °C/h to room temperature and stirred overnight. The product was collected at 22 °C on a vacuum filter and washed with 1:4 (v/v) 2-PrOH/ n-heptane (2 x 50 ml). After drying on the filter for 1-2 hours the weight of product was 25.5 g. The material was homogenized in a stainless steel blender to pulverize and blend the more granular solid component. The resulting pale beige powder (25.37 g) was dried in a vacuum oven at 50 °C. The dry weight was 25.34 g. The residual 2-propanol and n- heptane were estimated at <0.05 wt% each by 1H NMR analysis. The yield was 90.5% after correcting the X-hydrate for solvent and water content. Residual Pd was 21 ppm. The water content was 209 ppm by KF titration. The melting point was 100.7 °C by DSC analysis.

Table 1: Data for the isolated and dried Compound 1 – X-hydrate and anhydrous forms

M.P. by DSC; Pd by ICP; Purity by the API HPLC method; Chiral purity by HPLC; water content by KF titration; residual solvent estimated from ^:H NMR.

Table 2: Characterisation Data for Compounds 1 (X-hydrate) and 1 (anhydrous)

Needle like crystals Needle like crystals and agglomerates

PLM

particle size >100μιη particle size range from 5μπι-100μιη

0.59%w/w water uptake at 90%RH. 0.14%w/w water uptake at 90%RH.

GVS

No sample hysteresis No sample hysteresis

XRPD

No form change after GVS experiment No form change after GVS experiment post GVS

KF 2.4%w/w H₂0 Not obtained

<0.001mg/ml <0.001mg/ml

Solubility

pH of saturated solution = 8.6 pH of saturated solution = 8.7

Spectral Pattern 1 Spectral Pattern 2

Charcteristic bands/ cm^“1: Charcteristic bands/ cm ¹:

FT-IR 3499, 3378, 3213, 3172 3162

1612, 1598, 1588, 1522, 1502 1610, 1518, 1501 931, 903, 875, 855, 828, 816 927, 858, 841, 829, 812

The structure solution of Compound 1 anhydrous form was obtained by direct methods, full-matrix least-squares refinement on F ² with weighting w^‘1 = <5²{F₀²) + (0.0474P)² + (0.3258P), where P = (F₀²+2F ²)/3, anisotropic displacement parameters, empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. Final wR²

= {∑[w(F₀²-F_c²)²]/∑[w(F₀²)²]^m} = 0.0877 for all data, conventional Ri = 0.0343 on F values of 8390 reflections with F₀ > 4a( F₀), S = 1.051 for all data and 675 parameters. Final Δ/a (max) 0.001, A/a(mean), 0.000. Final difference map between +0.311 and -0.344 e A^“3.

Below shows a view of two molecules of Compound 1 in the asymmetric unit of the anhydrous form showing the numbering scheme employed. Anisotropic atomic displacement ellipsoids for the non-hydrogen atoms are shown at the 50% probability level. Hydrogen atoms are displayed with an arbitrarily small radius. The absolute configuration of the molecules has been determined to be R.

EXAMPLE 3

Compound 1 Ethanol Solvate Recrystallization

Compound 1 X-hydrate (50 mg) was suspended in -40 volumes of 15% H₂0/EtOH. The suspension was then placed in an incubation chamber for maturation. The maturation protocol involved treating the suspension to a two-temperature cycle of 50 °C/ ambient temperature at 8 hours per cycle for 3 days with constant agitation. After maturation, the suspension was cooled in a fridge at 4°C for up to 2 days to encourage the formation of crystals. Then, the solvent was removed at RT and the sample was vacuum dried at 30°C -35°C for up to 1 day. Suitable crystals formed on cooling were harvested and characterized.

Table 4: Single Crystal Structure of 1 Ethanol solvate

Molecular formula C25H22F7N5O3

The structure solution of Compound 1 ethanol solvate was obtained by direct methods, full-matrix least-squares refinement on F ² with weighting w^‘1 = σ²^²) + (0.0450P)² + (0.5000P), where P = (F₀²+2F ²)/3, anisotropic displacement parameters, empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. Final wR² = {∑[w(F₀²-F ²)²]/∑[w(F₀²)²]^m} = 0.0777 for all data, conventional Ri = 0.0272 on F values of 4591 reflections with F₀ > 4σ( F₀), S = 1.006 for all data and 370 parameters. Final Δ/σ (max) 0.000, A/a(mean), 0.000. Final difference map between +0.217 and -0.199 e A^“3.

Below shows a view of the asymmetric unit of the ethanol solvate from the crystal structure showing the numbering scheme employed. Anisotropic atomic displacement ellipsoids for the non-hydrogen atoms are shown at the 50% probability level. Hydrogen atoms are displayed with an arbitrarily small radius. The asymmetric unit shows stoichiometry of 1 : 1 for solvent of crystallisation to Compound 1.

EXAMPLE 4

Compound 1 1.5 Hydrate Recrystallization

Compound 1 X-hydrate (50 mg) was suspended in -40 volumes of 15% Η₂0/ΙΡΑ. The suspension was then placed in an incubation chamber for maturation. The maturation protocol involved treating the suspension to a two-temperature cycle of 50 °C/ ambient temperature at 8 hours per cycle for 3 days with constant agitation. After maturation, the suspension was cooled in a fridge at 4°C for up to 2 days to encourage the formation of crystals. Then, the solvent was removed at RT and the sample was vacuum dried at 30°C -35°C for up to 1 day. Suitable crystals formed on cooling were harvested and characterized.

Table 5: Single Crystal Structure of 1 1.5 Hydrate

The structure solution of Compound 1 1.5 hydrate was obtained by direct methods, full-matrix least-squares refinement on F ² with weighting w^‘1 = ^(F ²) + (0.1269P)² + (0.0000P), where P = (F₀²+2F ²)/3, anisotropic displacement parameters, empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. Final wR² = {∑[w(F ²-F ²)²]/∑[w(F ²)²] ^m} = 0.1574 for all data, conventional Ri = 0.0668 on F values of 2106 reflections with F₀ > 4σ( F₀), S = 1.106 for all data and 361 parameters. Final Δ/σ (max) 0.000, A/a(mean), 0.000. Final difference map between +0.439 and -0.598 e A^“3.

Below shows a view of the asymmetric unit of the 1.5 hydrate from the crystal structure showing the numbering scheme employed. Anisotropic atomic displacement ellipsoids for the non-hydrogen atoms are shown at the 50% probability level. Hydrogen atoms are displayed with an arbitrarily small radius. The asymmetric unit shows stoichiometry of 1.5: 1 for water to Compound 1.

EXAMPLE 5

Human Pharmacokinetic Comparison of Compound 1 X-Hydrate and Compound 1 Anhydrous Form

Table 6 compares human multiple-dose pharmacokinetic (PK) parameters between dosing with Compound 1 X-hydrate and Compound 1 Anhydrous form. Compound 1 X-hydrate was dosed at 600 mg twice daily (bid) for three days followed by dosing at 300 mg once daily (qd) for 10 days. Compound 1 Anhydrous form was dosed at 300 mg qd for 14 days. Despite the higher initial dosing amount and frequency (i.e., 600 mg bid) of Compound 1 X-hydrate, Compound 1 Anhydrous form surprisingly displayed higher maximal concentration (C_max) and higher area-under-the-curve (AUC) than Compound 1 X-hydrate.

Table 6. Comparison of Multiple Dose PK between Compound 1 X-Hydrate and Compound 1

Anhydrous Polymorph

Further characterization of the various polymorph forms of compound 1 are detailed in the accompanying figures.

PATENT

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2015143154

Examples

General Experimental Procedures

Definitions of variables in the structures in schemes herein are commensurate with those of corresponding positions in the formulae delineated herein.

Synthesis of 1 or la

la

A process to prepare enantiopure compound 1 or la is disclosed. Syntheses of lor la may be accomplished using the example syntheses that are shown below (Schemes 1-4). The preparation of precursor ketone 3-Br is performed starting with reaction of 2,5-dibromo-pyridine with ethyl 2-bromo-difluoroacetate to produce ester 2-Br. This ester is reacted with morpholine to furnish morpholine amide 2b-Br, followed by arylation to provide ketone 3-Br.

Scheme 1. Synthesis of ketone 3-Br

Ketone 3 may be prepared in an analogous fashion as described in Scheme 1 starting from corresponding substituted 2-bromo-pyridines, which can be prepared using according to synthetic transformations known in the art and contained in the references cited herein (Scheme 2).

Scheme 2. Synthesis of ketone 3

R₁ = halo, -0(C=0)-alkyl, -0(C=0)-substituted alkyl, -0(C=0)-aryl, -0(C=0)-substituted aryl, -0(C=0)-0-alkyl, – 0(C=0)-0-substituted alkyl, -0(C=0)-0-aryl, -0(C=0)-0-substituted aryl, -0(S0₂)-alkyl, -0(S0₂)-substituted alkyl, 0(S0₂)-aryl, or -0(S0₂)-substituted aryl.

Alternatively, compound 1 (or la, the enantiomer of 1, or mixtures thereof) can be prepared according to Scheme 3 utilizing amino-alcohols ±4b or ±1-6. Epoxides 4 and 5 can be prepared by reacting ketones 3 and 1-4 with trimethylsulfoxonium iodide (TMSI) in the presence of a base (e.g., potassium i-butoxide) in a suitable solvent or a mixture of solvents (e.g., DMSO or THF). Also, as indicated in Scheme 3, any of pyridine compounds, 3, 4, ±4b, 4b, or 6, can be converted to the corresponding 4-CF₃O-PI1 analogs (e.g., 1-4, 5, ±1-6, 1-6*, or 1 or the corresponding enantiomers, or mixtures thereof) by cross-coupling with (4-trifluoromethoxyphenyl)boronic acid (or the corresponding alkyl boronates or pinnacol boronates or the like), in a suitable solvent system (e.g., an organic-aqueous solvent mixture), in the presence of a transition metal catalyst (e.g., (dppf)PdCl2; dppf = 1,1′-(diphenylphosphino)ferrocene), and in the presence of a base (e.g., KHCO₃, K2CO₃, CS2CO₃, or Na₂CC>₃, or the like). Epoxides 4 and 5 can then be converted into amino-alcohols ±4b and ±1-6 through ammonia-mediated epoxide opening using ammonia in a suitable solvent (e.g., MeOH, EtOH, or water). Racemic amino-alcohols ±4b and ±1-6 can then be enantio-enriched by exposure to a chiral acid (e.g., tartaric acid, di-benzoyltartaric acid, or di-p-toluoyltartaric acid or the like) in a suitable solvent (e.g., acetonitrile, isopropanol, EtOH, or mixtures thereof, or a mixture of any of these with water or MeOH; preferably acetonitrile or a mixture of acetonitrile and MeOH, such as 90:10, 85: 15, or 80:20 mixture) to afford compounds 4b (or 4c, the enantiomer of 4b, or mixtures thereof) or 1-6* (or 1-7*, the enantiomer of 1-6*, or mixtures thereof). Subsequent treatment with TMS-azide in the presence of trimethylorthoformate and sodium acetate in acetic acid would yield compounds 20 (or 20a, the enantiomer of 20, or mixtures thereof) or 1 (or la, the enantiomer of 1, or mixtures thereof) (US 4,426,531).

Scheme 3. Synthesis of 1 or la via TMSI Epoxidation Method

R-ι = halo, -0(C=0)-alkyl, -0(C=0)-substituted alkyl, -0(C=0)-aryl, -0(C=0)- substituted aryl, -0(C=0)-0-alkyl, -0(C=0)-0-substituted alkyl, -0(C=0)-0- aryl, -0(C=0)-0-substituted aryl, -0(S0₂)-alkyl, -0(S0₂)-substituted alkyl, – 0(S0₂)-aryl, or -0(S0₂)-substituted aryl.

Compound 1 (or la, the enantiomer of 1, or mixtures thereof) prepared by any of the methods presented herein can be converted to a sulfonic salt of formula IX (or IXa, the enantiomer of

IX, or mixtures thereof), as shown in Scheme 4. This can be accomplished by a) combining compound 1 (or la, the enantiomer of 1, or mixtures thereof), a crystallization solvent or crystallization solvent mixture (e.g., EtOAc, i^‘PrOAc, EtOH, MeOH, or acetonitrile, or o

Z-S-OH

combinations thereof), and a sulfonic acid o (e.g., Z = Ph, p-tolyl, Me, or Et), b) diluting the mixture with an appropriate crystallization co-solvent or crystallization co-solvent mixture (e.g., pentane, methyl i-butylether, hexane, heptane, or toluene, or combinations thereof), and c) filtering the mixture to obtain a sulfonic acid salt of formula IX (or IXa, the enantiomer of IX, or mixtures thereof).

Scheme 4. Synthesis of a Sulfonic Acid Salt of Compound 1 or la

EXAMPLE 1: Preparation of l-(2,4-difluorophenyl)-2,2-difluoro-2-(5-(4- (trifluoromethoxy)phenyl)pyridin-2-yl)ethanone (1-4).

la. ethyl 2-(5-bromopyridin-2-yl)-2,2-difluoroacetate (2)

2-Br
Typical Procedure for Preparing 2-Br

Copper ( 45μιη, 149g, 0.198moles, 2.5 equiv) was placed into a 3L, 3-neck round bottom flask equipped with a condenser, thermocouple, and an overhead stirrer. DMSO (890 mL, 4.7 vol. based on ethyl 2-bromo-2,2-difluoroacetate) and 14mL of concentrated sulfuric acid was added and the mixture stirred for 30 minutes. The mixture self-heated to about 31°C during the stir time. After cooling the contents to 23°C, 2,5-dibromopyridine 1 (277g, 1.17 moles, 1.5 eq) was added to the reaction mixture. The temperature of the contents decreased to 16°C during a 10 minute stir time. 2-bromo-2,2-difluoroacetate (190 g, 0.936 moles, 1.0 eq) was added in one portion and the mixture stirred for 10 min. The flask contents were warmed to 35°C and the internal temperature was maintained between 35-38° for 18 h. In-process HPLC showed 72% desired 2-Br. The warm reaction mixture was filtered through filter paper and the collected solids washed with 300mL of 35°C DMSO. The solids were then washed with 450mL of n-heptane and 450mL of MTBE. The collected filtrate was cooled to about 10°C and was slowly added 900mL of a cold 20% aqueous NH₄C1 solution, maintaining an internal temperature of <16°C during the addition. After stirring for 15 minutes, the layers were settled and separated. The aqueous layer was extracted 2 X 450mL of a 1: 1 MTBE: n-heptane mixture. The combined organic layers were washed 2 X 450mL of aqueous 20% NH₄CI and with 200mL of aqueous 20% NaCl. The organic layer was dried with 50g MgS0₄ and the solvent removed to yield 2-Br as a dark oil. Weight of oil = 183g ( 70% yield by weight) HPLC purity ( by area %) = 85%. *H NMR (400 MHz, d₆-DMSO) : 58.86 (m, 1H), 8.35 ( dd, J= 8.4, 2.3Hz, 1H), 7.84 (dd, J= 8.3, 0.6Hz, 1H), 4.34 ( q, J= 7.1Hz, 2H), 1.23 ( t, J= 7.1Hz, 3H). MS m/z 280 ( M+H⁺), 282 (M+2+H⁺).

lb. 2-(5-bromopyridin-2-yl)-2,2-difluoro-l-morpholinoethanone (2b-Br)

Table 2 illustrates the effects of the relative proportions of each of the reagents and reactants, and the effect of varying the solvent had on the overall performance of the transformation as measured by the overall yield and purity of the reaction.

Table 2. Process Development for the Preparation of compound 2b-Br

Note: All reactions were conducted at 22- 25°C

Typical Procedure for Converting 2-Br to 2b-Br

Crude ester 2-Br (183g, 0.65moles) was dissolved in 1.5L of n-heptane and transferred to a 5L 3-neck round bottom flask equipped with a condenser, an overhead stirrer and a thermocouple. Morpholine ( 248g, 2.85 moles, 4.4 equiv.) was charged to the flask and the mixture warmed to 60°C and stirred for 16 hours. In-process HPLC showed <1 % of ester 2-Br. The reaction mixture was cooled to 22-25 °C and 1.5L of MTBE was added with continued cooling of the mixture to 4°C and slowly added 700mL of a 30%, by weight, aqueous citric acid solution. The temperature of the reaction mixture was kept < 15°C during the addition. The reaction was stirred at about 14°C for one hour and then the layers were separated. The organic layer was washed with 400mL of 30%, by weight, aqueous citric acid solution and then with 400mL of aqueous 9% NaHC0₃. The solvent was slowly removed until 565g of the reaction mixture

remained. This mixture was stirred with overhead stirring for about 16 hours. The slurry was filtered and the solids washed with 250mL of n-heptane. Weight of 2b-Br = 133g. HPLC purity (by area %) 98%.

This is a 44% overall yield from 2,5-dibromopyridine.

*H NMR (400 MHz, d₆-DMSO): 58.86 (d, J= 2.3Hz, 1H), 8.34 (dd, J= 8.5, 2.3Hz, 1H), 7.81 (dd, J = 8.5, 0.5Hz, 1H), 3.63-3.54 ( m, 4H), 3.44-3.39 (m, 2H), 3.34-3.30 ( m, 2H). MS m/z 321 (M+H⁺), 323 (M+2+H⁺).

lc. 2-(5-bromopyridin-2-yl)-l-(2,4-difluorophenyl)-2,2-difluoroethanone (3-Br)

Process Development

Table 3 illustrates the effects of the relative proportions of each of the reagents and reactants, and the effect of varying the temperature had on the overall performance of the transformation as measured by the overall yield and purity of the reaction.

Table 3. Process Development for the Preparation of bromo-pyridine 3-Br

Typical Procedure for Converting 2b-Br to 3-Br

Grignard formation:

Magnesium turnings (13.63 g, 0.56 moles) were charged to a 3-neck round bottom flask equipped with a condenser, thermocouple, addition funnel, and a stir bar. 540 mL of anhydrous tetrahydrofuran was added followed by l-Bromo-2,4-difluorobenzene (16.3 mL, 0.144 moles). The contents were stirred at 22-25°C and allowed to self -heat to 44°C. 1- Bromo-2,4-difluorobenzene ( 47mL, 0.416 moles) was added to the reaction mixture at a rate that maintained the internal temperature between 40-44°C during the addition. Once the addition was complete, the mixture was stirred for 2 hours and allowed to cool to about 25° during the stir time.

This mixture was held at 22-25°C and used within 3-4 hours after the addition of l-bromo-2,4-difluorobenzene was completed.

Coupling Reaction

Compound 2b-Br (120 g, 0.0374 moles) was charged to a 3-neck round bottom flask equipped with a condenser, thermocouple, and an overhead stirrer. 600 mL of anhydrous

tetrahydrofuran was added. The flask contents were stirred at 22°C until a clear solution was obtained. The solution was cooled to 0-5°C. The previously prepared solution of the Grignard reagent was then added slowly while maintaining the reaction temperature at 0-2°C. Reaction progress was monitored by HPLC. In-process check after 45 minutes showed <1% amide 2b-Br remaining. 2 N aqueous HC1 (600 mL, 3 vol) was added slowly maintaining the temperature below 18°C during the addition. The reaction was stirred for 30 minutes and the layers were separated. The aqueous layer was extracted with 240mL MTBE. The combined organic layers were washed with 240mL of aqueous 9% NaHCC>3 and 240mL of aqueous 20% NaCl. The organic layer was dried over 28g of MgS04 and removed the solvent to yield 3-Br (137g) as an amber oil.

HPLC purity ( by area %) = -90%; *H NMR (400 MHz, d₆-DMSO) : 58.80 (d, J= 2.2Hz, 1H), 8.41 ( dd, J= 8.3, 2.3Hz, 1H), 8.00 (m, 2H), 7.45 ( m, 1H), 7.30 ( m, 1H). MS m/z 348 (M+H⁺), 350 (M+2+H⁺).

Id. l-(2,4-difluorophenyl)-2,2-difluoro-2-(5-(4-(trifluoromethoxy)phenyl)pyridin-2-yl)ethanone (1-4)

Typical Procedure for Converting 3-Br to 1-4

Into a 250 mL reactor were charged THF (45 mL), water (9.8 mL), bromo-pyridine 3-Br (6.0 g, 17.2 mmoles), 4-(trifluoromethoxy)phenylboronic acid (3.57 g, 17.3 mmoles), and Na₂CC>3 (4.55 g, 42.9 mmoles). The stirred mixture was purged with nitrogen for 15 min. The catalyst (Pd(dppf)Cl₂ as a CH₂C1₂ adduct, 0.72 g, 0.88 mmoles) was added, and the reaction mixture was heated to 65 °C and held for 2.5 h. The heat was shut off and the reaction mixture was allowed to cool to 20-25 °C and stir overnight. HPLC analysis showed -90% ketone 1-4/hydrate and no unreacted bromo-pyridine 3-Br. MTBE (45 mL) and DI H₂0 (20 mL) were added, and the quenched reaction was stirred for 45 min. The mixture was passed through a plug of Celite (3 g) to remove solids and was rinsed with MTBE (25 mL). The filtrate was transferred to a separatory funnel, and the aqueous layer drained. The organic layer was washed with 20% brine (25 mL). and split into two portions. Both were concentrated by rotovap to give oils (7.05 g and 1.84 g, 8.89 g total, >100% yield, HPLC purity -90%). The larger aliquot was used to generate hetone 1-4 as is. The smaller aliquot was dissolved in DCM (3.7 g, 2 parts) and placed on a pad of Si0₂ (5.5 g, 3 parts). The flask was rinsed with DCM (1.8 g), and the rinse added to the pad. The pad was eluted with DCM (90 mL), and the collected filtrate concentrated to give an oil (1.52 g). To this was added heptanes (6 g, 4 parts) and the mixture stirred. The oil crystallized, resulting in a slurry. The slurry was stirred at 20-25 °C overnight. The solid was isolated by vacuum filtration, and the cake washed with heptanes (-1.5 mL). The cake was dried in the vacuum oven (40-45 °C) with a N₂ sweep. 0.92 g of ketone 1-4 was obtained, 60.1% yield (corrected for aliquot size), HPLC purity = 99.9%.

TMSI Epoxidation Method

3d. 2-((2-(2,4-difluorophenyl)oxiran-2-yl)difluoromethyl)-5-(4-(trifluoromethoxy)phenyl)pyridine (5)

Typical Procedure for Converting 1-4 to 5

i-BuOK (2.22 g, 19.9 mmoles), TMSI (4.41 g, 20.0 mmoles), and THF (58.5 mL) were charged to a reaction flask, and the cloudy mixture was stirred. DMSO (35.2 mL) was added, and the clearing mixture was stirred at 20-25°C for 30 min before being cooled to 1-2°C.

Ketone 1-4 (crude, 5.85 g, 13.6 mmoles) was dissolved in THF (7.8 mL), and the 1-4 solution was added to the TMSI mixture over 12.75 min, maintaining the temperature between 1.5 and 2.0°C. The reaction was held at 0-2°C. After 1 h a sample was taken for HPLC analysis, which showed 77.6% epoxide 5, and no unreacted ketone 1-4. The reaction was quenched by the slow addition of 1 N HC1 (17.6 mL), keeping the temperature below 5°C. After 5 min 8% NaHCC>3 (11.8 mL) was added slowly below 5°C to afford a pH of 8. The reaction mixture was transferred to a separatory funnel, and the layers were separated. The aqueous layer was extracted with MTBE (78 mL), and the combined organic layers were washed with 20% NaCl (2 x 20 mL). After concentration, 7.36 g of a dark oil was obtained. HPLC of the crude oil shows it contained 75% epoxide 5. The oil was dissolved in DCM (14.7 g, 2 parts) and the solution placed on a pad of Si0₂ (22 g, 3 parts). The flask was rinsed with DCM (7.4 g, 1 part) and the rinse placed on the pad. The pad was eluted with DCM (350 mL) to give an amber filtrate. The filtrate was concentrated by rotovap, and when space in the flask allowed, heptane (100 mL) was added. The mixture was concentrated until 39.4 g remained in the flask, causing solid to form. The suspension was stirred for 70 min at 20-25°C. Solid was isolated by vacuum filtration, and the cake washed with heptane (10 mL) and pulled dry on the funnel. After drying in a vacuum oven (40-45 °C) with a N₂ sweep, 3.33 g solid was obtained, 55.1% yield from bromo-pyridine 3, HPLC purity = 99.8%.

3e. 3-amino-2-(2,4-difluorophenyl)-l,l-difluoro-l-(5-(4-(trifluoromethoxy)phenyl)pyridin-2-yl)propan-2-ol (±1-6)

Process Development

Table 8 illustrates the effects of the relative proportions of each of the reagents and reactants, the effect of varying the solvent, and the effect of varying the temperature had on the overall performance of the transformation as measured by the overall yield and purity of the reaction. Table 8. Process Development for the Preparation of ±1-6

Typical Procedure for Converting 5 to +1-6

Epoxide 5 (2.17 g, 4.89 mmoles) was combined in a glass pressure tube with methanol (48 mL) and aqueous ammonia (19.5 mL). The tube was sealed and placed in an oil bath held at 54°C, with stirring. After 15 h the tube was removed from the bath, cooled, and the reaction sampled for HPLC, which showed 93.6% amino-alcohol ±1-6 and 6.0% di-adducts. To the reaction were added MTBE (48 mL) and 20% NaCl (20 mL). The layers were separated and the aqueous layer extracted with MTBE (20 mL). The combined organic layers were washed with H₂0 (20 mL) and transferred to a rotovap flask. Heptane (20 mL) was added, and the solution was concentrated until 16.9 g remained in the flask. An H₂0 layer appeared in the flask, and was pipetted out, leaving 12.8 g. Compound 1-6 seed was added, and the crystallizing mixture was stirred at 20-25 °C overnight. The flask was cooled in an ice bath for 2 h prior to filtration, and the isolated solid was washed with cold heptane (5 mL), and pulled dry on the funnel. After drying in a vacuum oven (40-45°C) for several hours 1.37 g of amino-alcohol ±1-6 was obtained, 60.8% yield, HPLC purity = 98.0%.

3f . 3-amino-2-(2,4-difluorophenyl)- 1 , 1-difluoro- 1 -(5-(4-(trifluoromethoxy)phenyl)pyridin-2- yl)propan-2-ol (1-6* or 1-7*)

Process Development

Table 9 illustrates the initial screen performed surveying various chiral acid/solvent combinations. All entries in Table 9 were generated using 0.1 mmoles of amino-alcohol ±1-6, 1 equivalent of the chiral acid, and 1ml of solvent.

Table 9. Resolution of ±1-6 (Initial Screen)

Since the best results from Table 9 were generated using tartaric acid and di-p-toluoyltartaric acid, Table 10 captures the results from a focused screen using these two chiral acids and various solvent combinations. All entries in Table 10 were performed with 0.2 mmoles of amino-alcohol ±1-6, 87 volumes of solvent, and each entry was exposed to heating at 51 °C for lh, cooled to RT, and stirred at RT for 24h.

Table 10. Resolution of ±1-6 (Focused Screen)

Each of the three entries using di-p-toluoyltartaric acid in Table 10 resulted in higher levels of enantio-enrichment when compared to tartaric acid. As such, efforts to further optimize the enantio-enrichment were focusing on conditions using di-p-toluoyltartaric acid (Table 11).

Ό.6 equivalents used

ee sense was opposite from the other entries in the table (i.e., enantiomer of 1-6*)

Typical Procedure for Converting +1-6 to 1-6* or 1-7*

(This experimental procedure describes resolution of ±1-6, but conditions used for DPPTA resolution of 1-6 or 1-7 are essentially the same.)

Amino-alcohol ±1-6 (7.0 g, 15 mmoles) was dissolved in a mixture of acetonitrile (84 mL) and methanol (21 mL). (D)-DPTTA (5.89 g, 15 mmoles) was added, and the reaction was warmed to 50°C and held for 2.5 h. The heat was then removed and the suspension was allowed to cool and stir at 20-25 °C for 65 h. The suspension was cooled in an ice bath and stirred for an additional 2 h. Solid was isolated by vacuum filtration, and the cake was washed with cold 8:2 ACN/MeOH (35 mL). After drying at 50°C, 5.18 g of 1-6* or l-7*/DPPTA salt was isolated, HPLC purity = 99.0, ee = 74.

The 1-6* or l-7*/DPPTA salt (5.18 g) was combined with 8:2 ACN/MeOH (68 mL) and the suspension was heated to 50°C and held for 20 min. After cooling to 20-25 °C the mixture was stirred for 16 h. Solids were isolated by vacuum filtration, and the cake washed with cold 8:2 ACN/MeOH (30 mL), and pulled dry on the funnel. 2.82 g of 1-6* or l-7*/DPPTA salt was obtained, 44.4% yield (from crude ±1-6), ee = 97.5. The resulting solids were freebased to provide 1-6* or 1-7* with the same achiral and chiral purity as the DPPTA salt.

EXAMPLE 4: Preparation of 2-(2.4-difluorophenyl -l.l-difluoro-3-(lH-tetrazol-l-yl -l-(5-(4-(trifluoromethoxy)phenyl)pyridin-2-yl)propan-2-ol (1 or la).

The procedure used to generate compound 1 or la is as described in US 4,426,531. Table 13 illustrates the efficient and quantitative nature of this procedure as performed on amino- alcohol 1-6* or 1-7* produced from both the TMS-cyanohydrin method and the TMSI- epoxidation method.

Table 13. Formation of Compound 1 or la

EXAMPLE 5: 2-(2.4-difluorophenyl -l.l-difluoro-3-(lH-tetrazol-l-yl -l-(5-(4- (trifluoromethoxy)phenyl)pyridin-2-yl)propan-2-ol benzenesulfonate (1 or la-BSA).

Typical Procedure for Converting 1 or la to 1 or la-BSA

46.6 g of compound 1 or la was dissolved in ethylacetate (360ml). The solution was filtered through a glass microfiber filter and placed in a 2 L reaction flask equipped with an overhead stirrer, condenser, and a J-Kem thermocouple. Pharma-grade benzenesulfonic acid (BSA, 14.39g, leq) was dissolved in ethyl acetate (100ml). The BSA solution was filtered through a glass microfiber filter and added to the stirred 1 or la solution in one portion. The mixture was warmed to 60-65 °C; precipitation of the 1 or la/BSA salt occurred during the warm up period. The slurry was held for 60 minutes at 60-65 °C. The suspension was allowed to slowly cool to 22 °C and was stirred at 20-25 °C for 16 hours. n-Heptane (920ml) was charged in one portion and the suspension was stirred at 22 °C for an additional 90 minutes. The slurry was filtered and the collected solids washed with n-heptane (250ml). The isolated solids were placed in a vacuum oven at 50 °C for 16 hours. 52.26g (86% yield) of 1 or la

benzenesulfonate was obtained.

*H NMR (400 MHz, DMSO-d6 + D₂0): 89.16 (s, 1H), 8.95 (d, J = 2.1 Hz, 1H), 8.26 (dd, J = 8.2, 2.3 Hz, 1H), 7.96-7.89 (m, 2H), 7.66-7.61 (m, 2H), 7.59 (dd, J = 8.3, 0.4 Hz, 1H), 7.53 (br d, J = 8.0 Hz, 2H), 7.38-7.15 (m, 5H), 6.90 (dt, J = 8.3, 2.5 Hz, 1H), 5.69 (d, J = 14.8 Hz, 1H), 5.15 (d, J = 15.2 Hz, 1H).

Further results are in Table 14.

Table 14. Formation of 1 or la-BSA

( ) (%ee) Yield Purity (%) ee

97.9 95.9 84% 98.2 97.1

Figures 1-2 contain the analytical data for 1 or la-BSA prepared by the TMSI-epoxidation process.

EXAMPLE 6: 5-bromo-2-((2-(2,4-difluorophenyl)oxiran-2-yl)difluoromethyl)pyridine -Br).

Typical Procedure for Converting 3-Br to 4-Br

KOtBu ( 41.7g, 0.372moles, 1.05 equiv) and trimethylsulfoxonium iodide ( 85.7g,

0.389moles, 1.1 equiv) were charged to a 3L 3-neck round bottom flask equipped with an overhead stirrer, a thermocouple and an addition funnel. 1.2L of anhydrous THF and 740mL of DMSO were added to the flask and stirred at 22-25 °C for 70 minutes. The contents were cooled to 0°C. Crude ketone 3 was dissolved in 250mL of anhydrous THF and slowly added the ketone 3-Br solution to the reaction mixture over 20 minutes while maintaining a reaction temperature at < 3°C during the addition and stirred at 0°C for one hour. In-process HPLC showed <1% ketone 3-Br remaining. 200mL of IN HC1 was slowly added maintaining a reaction temperature of < 6°C during the addition. After stirring for 30 minutes the layers were separated and the aqueous layer was extracted with 375mL of MTBE. The combined organic layers were washed with 375mL of aqueous 9% NaHCC>3 and with 375mL of aqueous 20% NaCl. The solvent was removed to yield 4-Br as a brown waxy solid.

Weight of crude epoxide 4-Br = 124.6g; *H NMR (400 MHz, d₆-DMSO) : 58.82 (d, J= 2.3Hz, 1H), 8.21 ( dd, J= 8.3, 2.3Hz, 1H), 7.50 (dd, J= 8.3, 0.5Hz, 1H), 7.41 ( m, 1H), 7.25 ( m, 1H), 7.10 (m,lH), 3.40 ( d, J= 4.5Hz, 1H), 3.14 ( m, 1H). MS m/z 362 (M+H⁺), 364 (M+2+H⁺).

EXAMPLE 7: 3-amino-l-(5-bromopyridin-2-yl)-2-(2,4-difluorophenyl)-l,l-difluoropropan-2-ol (4b-Br).

Typical Procedure for Converting 4-Br to 4b-Br

Crude epoxide 4-Br ( 54.4g, 0.15moles) was placed into a Schott autoclave bottle equipped with a stir bar. 550mL of MeOH was added to the bottle and stirred for 90 minutes at 22-25 °C. Concentrated NH₄OH ( 550mL, 7.98 moles, 53 equiv) was added to the epoxide 4-Br

solution. The bottle was sealed and placed in an oil bath at 55 °C. The mixture was stirred at 55°C for 17 hours. The bottle was removed from the oil bath and cooled to 22-25°C. In-process HPLC showed <1% epoxide 4-Br remaining. The solvent was removed via rotary evaporation until 362g ( 37%) of the reaction mass remained. 500mL of MTBE was added and cooled the mixture to 8°C. 500mL of 6N HCl was slowly added maintaining the reaction temperature between 8 – 12°C during the addition. After stirring for 10 minutes, the layers were separated. The MTBE layer was extracted with 350mL of 6N HCl. The combined aqueous layers were washed with 250mL MTBE and 2 X 250mL heptane. MTBE, 250mL, was added to the aqueous layer and the mixture was cooled to 2°C. 344g of KOH was dissolved in 500mL of water. The KOH solution was slowly added to the reaction mixture over one hour while maintaining the temperature at <19°C. After stirring for 15 minutes, the layers were separated. The aqueous layer was extracted with 250mL MTBE. The combined organic layers were washed with 250mL of aqueous 20% NaCl and the solvent was removed to yield ±4b-Br as a dark oil. Weight of crude amino alcohol ±4b-Br = 46.0g. HPLC purity ( by area %) = 92%; *H NMR (400 MHz, d₆-DMSO) : 58.67 (d, J= 2.2Hz, 1H), 8.15 ( dd, J= 8.6, 2.4Hz, 1H), 7.46 (m, 1H), 7.40 ( dd, J= 8.5, 0.7Hz, 1H), 7.10 ( m, 1H), 7.00 (m,lH), 3.37 (dd, J= 13.7, 2.1Hz, 1H), 3.23 ( dd, J= 13.7, 2.7, 1H). MS m/z 379 (M+H⁺), 381 (M+2+H⁺).

EXAMPLE 8: 3-amino-l-(5-bromopyridin-2-yl -2-(2.4-difluorophenyl -l.l-difluoropropan-2-ol (4b-Br or 4c-Br).

Typical Procedure for Converting 4-Br to 4b-Br or 4c-Br

Crude amino alcohol ±4b-Br ( 42.4, O. llmoles) was dissolved in 425mL of 8:2 IPA: CH₃CN. The solution was charged to a 1L 3-neck round bottom flask equipped with a condenser, overhead stirrer and a thermocouple. Charged di-p-toluoyl-L-tartaric acid ( 21.6g, 0.056moles, 0.5 equiv) to the flask and warmed the contents to 52°C. The reaction mixture was stirred at 52°C for 5 hours, cooled to 22-25°C and stirred for 12 hours. The slurry was cooled to 5-10°C and stirred for 90 minutes. The mixture was filtered and collected solids washed with 80mL of cold CH₃CN. The solids were dried in a vacuum oven 45-50°C. Weight of amino alcohol/ DPTTA salt = 17.4g

Chemical purity by HPLC ( area %) = 98.5%; Chiral HPLC= 98.0% ee.

13.60g of the amino alcohol/ DPTTA salt was placed into a 250mL flask with a stir bar and to this was added lOOmL of MTBE and lOOmL of 10% aqueous K2CO₃solution. The reaction was stirred until complete dissolution was observed. The layers were separated and the aqueous layer was extracted with 50mL of MTBE. The combined MTBE layers were washed with 50mL of 20% aqueous NaCl and the solvent removed to yield 8.84 (98%) of 4b-Br or 4c-Br as a light yellow oil.

EXAMPLE 9: 3-amino-2-(2,4-difluorophenyl)-l J-difluoro-l-(5-(4-(trifluoromethoxy)phenyl)pyridin-2-yl)propan-2-ol (1-6* or 1-7*).

Typical Procedure for Converting 4b-Br or 4c-Br to 1-6* or 1-7*

Amino alcohol 4b-Br or 4c-Br (8.84g, 0.023moles, 1 equiv) was dissolved in 73mL of n-propanol. The solution was transferred to a 250mL 3-neck round bottom flask equipped with a condenser, thermocouple, stir bar and septum. 17mL of water was added and stirred at 22-25°C for 5 minutes. To the reaction was added K2CO₃ ( 9.67g, 0.07moles, 3 equiv), 4-(trifluoromethoxy)phenylboronic acid ( 5.76g, 0.028moles, 1.2 equiv.) and Pd(dppf)Cl₂ as a CH₂Cl₂ adduct ( 0.38g, 0.47mmoles, 0.02 equiv) to the flask. After the mixture was purged with nitrogen for 10 minutes, the reaction was then warmed to 85-87°C and stirred at 85-87°C for 16 hours. HPLC analysis showed < 1% of the amino alcohol 4b-Br or 4c-Br remaining. The mixture was cooled to 22-25 °C, then 115mL of MTBE and 115mL of water were added and stirred for 30 minutes. The layers were separated and the organic layer was washed with 2 X 60mL of 20% aqueous NaCl. The solvent was removed to yield 12.96g ( 121% yield) of 1-6* or 1-7* as a crude dark oil. It should be noted that the oil contains residual solvent, Pd and boronic acid impurity.

‘ll NMR (400 MHz, d₆-DMSO) : 58.90 (d, J= 2.2Hz, 1H), 8.22 ( dd, J= 8.3, 2.3Hz, 1H), 7.91 (m, 2H), 7.54 ( m, 4H), 7.14 ( m, 1H), 7.02 (m,lH), 3.41 (m, 1H), 3.27 ( dd, J= 14.0, 2.7, 1H). MS m/z 461 (M+H⁺⁾

CLIP

DOI: 10.1039/C6MD00222F

Fungal infections directly affect millions of people each year. In addition to the invasive fungal infections of humans, the plants and animals that comprise our primary food source are also susceptible to diseases caused by these eukaryotic microbes. The need for antifungals, not only for our medical needs, but also for use in agriculture and livestock causes a high demand for novel antimycotics. Herein, we provide an overview of the most commonly used antifungals in medicine and agriculture. We also present a summary of the recent progress (from 2010–2016) in the discovery/development of new agents against fungal strains of medical/agricultural relevance, as well as information related to their biological activity, their mode(s) of action, and their mechanism(s) of resistance.

////////VT 1129,  VIAMET, WO 2016149486,  Viamet Pharmaceuticals,  Antifungals,  Small molecules,  14-alpha demethylase inhibitors, Orphan Drug Status, Cryptococcosis, On Fast track, PHASE 1, VT-1129

O[C@@](Cn1cnnn1)(c2ccc(F)cc2F)C(F)(F)c3ccc(cn3)c4ccc(OC(F)(F)F)cc4

Ethyl 2-[(6,7-dimethoxyquinazolin-4-yl)amino]-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate (15b)

Yield: 76%; mp: 254–256°C; IR (cm⁻¹): 3200 (NH), 2974, 2854 (CH-aliphatic), 1656 (C=O); ¹H NMR (DMSO-d₆) δ ppm 1.03 (t, 3H, CH₃CH₂, J = 7.2 Hz), 1.21 (t, 2H, CH₂, J = 6.9 Hz), 2.88 (t, 2H, CH₂, J = 6.9 Hz), 3.40 (q, 2H, CH₂, J = 6.9 Hz), 3.88 (s, 3H, OCH₃), 3.91 (s, 3H, OCH₃), 3.96 (m, 4H, 2 CH₂), 4.24 (q, 2H, CH₃CH₂, J = 7.2 Hz), 7.40 (s, 1H, Ar-H), 7.62 (s, 1H, Ar-H), 8.99 (s, 1H, Ar-H), 12.00 (s, 1H, NH, D₂O exchangeable); Anal. Calcd for C₂₂H₂₅N₃O₄S: C, 61.81; H, 5.89; N, 9.83. Found: C, 61.93; H, 5.96; N, 9.98.

General procedure for the synthesis of compounds 15a,15b

A mixture of 4-chloro-6,7-dimethoxyquinazoline (1) (0.22 g, 1 mmol) and ethyl 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate (14a) or ethyl 2-amino-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylate (14b) (1 mmol) in isopropanol (15 mL) was heated under reflux for 10 h. The reaction was cooled, and the solid formed was filtered, dried, and crystallized from isopropanol.

Synthesis of 4-Heteroaryl–Quinazoline Derivatives as Potential Anti-breast Cancer Agents

A. E. Kassab, E. M. Gedawy, H. B. El-Nassan+

+Pharmaceutical Organic Chemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt

E-mail: hala_bakr@hotmail.com

DOI10.1002/jhet.2634, 

http://onlinelibrary.wiley.com/doi/10.1002/jhet.2634/full?elq_mid=11879&elq_cid=4828550

Asmaa Elsayed Abd Ellatief Kassab( A. E. Kassab)

4-Heteroaryl or heteroalkyl–quinazoline derivatives were prepared as dual epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitors. The new compounds were tested for their dual enzyme inhibition as well as their cytotoxic activity on MCF7 cell line. The results indicated that almost all the compounds showed moderate dual inhibition of both enzymes. Compound 3 (methyl piperidine-4-carboxylate derivative) showed the highest inhibitory activity against both enzymes with IC₅₀ 97.6 and 64.0 µM against EGFR and VEGFR-2 kinases, respectively. Most of the test compounds showed potent to moderate antitumor activity on MCF7 cell line. Five compounds (3, 9c, 11, 13, and 15b) showed potent cytotoxic activity with IC₅₀values between 10 and 17 µM.

Scheme 4.

Scheme 3.

Scheme 2.

Scheme 1.

CAIRO UNIVERSITY

LIBRARY.CAIRO UNIV

DOWNTOWN CAIRO

Dean of faculty of pharmacy, Cairo University, Dr. Azza Agha during the opening of the first international day at Faculty of Pharmacy.

DRUG APPROVALS BY DR ANTHONY MELVIN CRASTO …..FOR BLOG HOME CLICK HERE

Join me on Linkedin

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 amcrasto@gmail.com

//////////4-Heteroaryl–Quinazoline Derivatives,  Anti-breast Cancer Agents

N-(5-amino-2-tert-butyl)-11-fluorbenzol[f]thiazol-[4,5-h]-quinazolin-10-yl)-2,6-difluorbenzolsulfonamide = Dabrafenib_photo (2)

C23H18F3N5O2S2 (Mr = 517.09)

Solution of 5 mg (9.6 μmol) dabrafenib in 2 ml THF was irradiated at 365 nm with 5.4 W for 2 min. This procedure was repeated 18 times at room temperature. The reaction batches were combined. The total initial weight of dabrafenib was 101 mg (190 μmol). The solvent was removed under reduced pressure and the residue was purified by the flash chromatography (SiO2 reversed phase, MeOH/water gradient 50:50 to 100:0) to give compound 2 as a yellowish solid (36.2 mg, 70.0 μmol, yield: 37%).

1H-NMR (DMSO-d6 , 300 MHz): δ = 1.52 (s, 9 H, H-8), 7.28 (m, 2 H, NH2), 7.28 (ddd, 5 J = 0.4 Hz, 4 J = 1.7 Hz, 3 J = 8.5 Hz, 3 J = 8.9 Hz, 2 H, H-18), 7.59 (dd, 3 J = 7.4 Hz, 3 J = 7.8 Hz, 1 H, H-13), 7.71 (tt, 4 J = 6.1 Hz, 3 J = 8.5 Hz, 1 H, H-19), 8.56 (dd, 4 J = 0.9 Hz, 3 J = 9.3 Hz, 1 H, H-14), 9.79 (s, 1 H, H-2), 11.01 (s, 1 H, NH) ppm.

13C-NMR (DMSO-d6 , 300 MHz): δ = 30.4 (s, C-8), 38.3 (s, C-7), 110.9 (d, 4 JCF = 1.6 Hz, C-3), 113.4 (dd, 2 JCF = 22.7 Hz, 2 JCH = 3.5 Hz, C-18), 114.6 (d, 3 JCF = 10.3 Hz, C-9), 117.4 (d, 2 JCF = 16.1 Hz, C-16), 117.6 (dd, 4 JCF = 0.54 Hz, 2 JCH = 4.4 Hz, C-13), 120.8 (d, 2 JCF = 12.3 Hz, C-10), 125.4 (s, C-13), 129.3 (d, 3 JCF = 3.9 Hz, C-15), 130.6 (s, C-5), 135.9 (tt, 3 JCF = 10.9 Hz, 2 JCH = 3.3 Hz, C-19), 148.8 (dd, 2 JCF = 0.54 Hz, 2 JCH = 7.2 Hz, C-12), 149.2 (s, C-4), 150.1 (s, C-11), 157.1 160.5 (dd, 3 JFF = 257.3 Hz, 2 JCF = 3.61 Hz, C-4), 157.9 (s, C-2), 162.1 (s, C-1), 184.0 (s, C-6) ppm.

15N-HMBC (DMSO-d6 , 300 MHz): δ = 9.79/-119.60, 11.01/-268.37 ppm. 19F-NMR (DMSO-d6 , 300 MHz): δ = -121.03 (s, 1 F, F-11), -107.18 (m, 2 F, F-17) ppm.

HRMS (EI, 205 °C, THF): m/z = 517.0849 [M]+ .

LC-MS (ESI, 70 eV, MeOH): tR = 9.3 min; m/z (%) = 518.1 (100) [M+H]+

IR (ATR):  ̃ = 3490 (N-H), 3176 (arom. C-H), 2926 (C-H3), 1696 (N=N), 1613 (N-H), 1587, 1522, 1488, 1469 (arom. C=C), 1342 (sulfonamide), 1277, 1240, 1174 (C-F) cm-1 .

Photoinduced Conversion of Antimelanoma Agent Dabrafenib to a Novel Fluorescent BRAF^V600E Inhibitor

////////Photoinduced Conversion, Antimelanoma Agent,  Dabrafenib, Novel Fluorescent BRAF^V600E Inhibitor, BRAF^V600E; Dabrafenib, fluorescent probe,  kinase inhibitor,  photoinduced conversion

 

GPR40/FFAR1 is a G protein-coupled receptor predominantly expressed in pancreatic β-cells and activated by long-chain free fatty acids, mediating enhancement of glucose-stimulated insulin secretion. A novel series of substituted 3-(4-aryloxyaryl)propanoic acid derivatives were prepared and evaluated for their activities as GPR40 agonists, leading to the identification of compound 5, which is highly potent in in vitro assays and exhibits robust glucose lowering effects during an oral glucose tolerance test in nSTZ Wistar rat model of diabetes (ED₅₀ = 0.8 mg/kg; ED₉₀ = 3.1 mg/kg) with excellent pharmacokinetic profile, and devoid of cytochromes P450 isoform inhibitory activity

Synthesis of compound 5 is depicted in Scheme 1a.

The reductive amination1 of commercially available 3-thiophene-aldehyde (3) and isopropyl amine using sodium triacetoxyborohydride resulted in secondary amine intermediate 4. Compound 4 on further reductive amination under similar conditions with aldehyde intermediate, (S)-3-(4-((3-formylbenzyl)oxy)phenyl)hex-4-ynoic acid (8), afforded 2d in high yields. The aldehyde intermediate, 8 was obtained from (S)-3-(4-hydroxyphenyl)hex-4-ynoic acid (6) as shown in Scheme 1b. Acid 6 was synthesized via 5-step reported procedure using commercially available 4-hydroxybenzaldehyde and Meldrum’s acid.2 Resolution of racemic acid 6 was accomplished via diastereomeric salt formation with (1S,2R)-1-amino-2-indanol followed by salt break with aqueous acid to furnish compound 6. Treatment of 6 with of 40% aqueous tetrabutylphosphonium hydroxide (nBu4POH) in THF, followed by addition of 3-formyl benzyl bromide (7), afforded aldehyde intermediate 8. Compound 2d was further converted to its corresponding calcium salt (5) in two-step sequence with excellent chemical purity.

Scheme 1a. Synthesis of Compounds 2d and 5. Reagent and Conditions: (a) CH(CH3)2NH2, NaB(OAc)3H, CH3COOH, dry THF, 0 ᵒC to r.t., 16 h; (b) Comp 8, NaB(OAc)3H, CH3COOH, dry THF, 0 ᵒC to r.t., 16 h; (c) NaOH, MeCN/H2O, r.t., 3 h; (d) CaCl2, MeOH/H2O, r.t., 16 h.

BASE

(S)-3-(4-((3-((isopropyl(thiophen-3- ylmethyl)amino)methyl)benzyl)oxy)phenyl)hex-4-ynoic acid (1.557 g, 3.34 mmol, 43.0 % yield) as wax solid.

1H NMR (400 MHz, DMSO-d6): δ = 12.35 (br s, 1H), 7.44 (q, J = 3.2 Hz, 2H), 7.32 – 7.24 (m, 6H), 7.04 (d, J = 4.8 Hz, 1H), 6.94 (d, J = 8.4 Hz, 2H), 5.06 (s, 2H), 3.93 (d, J = 2.4 Hz, 1H), 3.51 (d, J = 8.8 Hz, 4H), 2.84 (sept, J = 6.4 Hz, 1H), 2.57 (d, J = 8 Hz, 2H), 1.77 (d, J = 2.4 Hz, 3H), 1.01 (d, J = 6.4 Hz, 6H);

13C NMR and DEPT: DMSO-d6, 100MHz):- δ = 172.35 (C), 157.63 (C), 142.13 (C), 141.44 (C), 137.42 (C), 133.93 (C), 128.73 (CH), 128.64 (CH), 128.43 (CH), 127.99 (CH), 127.73 (CH), 126.28 (CH), 122.21 (CH), 115.10 (CH), 81.16 (C), 78.52 (C), 69.69 (CH2), 52.90 (CH2), 48.64 (CH), 48.49 (CH2), 43.44 (CH2), 33.15 (CH), 17.92 (CH3), 3.66 (CH3);

MS (EI): m/z (%) = 462.35 (100) (M+H) + ;

IR (KBr): ν = 3433, 2960, 2918, 2810, 1712, 1608, 1510, 1383, 1240, 1174, 1109, 1018 cm-1 .

CA SALT

calcium (S)-3-(4-((3-((isopropyl(thiophen-3-yl methyl)amino)methyl)benzyl)oxy)phenyl)hex-4-ynoate (1.51 g, 1.536 mmol, 46% yield) as white powder. mp: 124.5 o C;

1H NMR (400 MHz, DMSO-d6): δ = 7.43 – 7.42 (m, 2H), 7.28 – 7.24 (m, 6H), 7.04 (d, J = 4.4 Hz, 1H), 6.89 (d, J = 8.4 Hz, 2H), 5.02 (s, 2H), 4.02 (s, 1H), 3.50 (d, J = 7.2 Hz, 4H), 2.84 – 2.77 (sept, J = 6.4 Hz, 1H), 2.43 (dd, J1 = 6.8 Hz, J2 = 7.2 Hz, 1H), 2.28 (dd, J1 = 6.8 Hz, J2 = 7.2 Hz, 1H), 1.73 (s, 3H), 0.99 (d, J = 6.4 Hz, 6H);

13C NMR and DEPT (100 MHz, DMSO-d6): δ = 177.78 (C), 157.23 (C), 142.11 (C), 141.4 (C), 137.46 (C), 135.81 (C), 128.83 (CH), 128.62 (CH), 128.40 (CH), 127.94 (CH), 127.69 (CH), 126.26 (CH), 122.18 (CH), 114.77 (CH), 83.18 (C), 77.32 (C), 69.66 (CH2), 52.89 (CH2), 48.59 (CH), 48.48 (CH2), 46.86 (CH2), 33.52 (CH), 17.88 (CH3), 3.78 (CH3);

MS (EI): m/z (%) = 462.05 (100) (M+H)+ ;

ESI-Q-TOF-MS: m/z [M+H]+ calcd for [C28H31NO3S + H]+ : 462.6280; found: 462.4988;

IR (KBr): ν = 3435, 2960, 2918, 2868, 2818, 1608, 1550, 1508, 1440, 1383, 1359, 1240 cm-1 ;

HPLC (% Purity) = 99.38%; Calcium Content (C56H60CaN2O6S2) Calcd.: 4.17%. Found: 3.99%.

 COMPD Ca salt

Calcium (S)-3-(4-((3-((isopropyl(thiophen-3-yl methyl)amino)methyl)benzyl)oxy)phenyl)hex-4-ynoate

Identification of an Orally Efficacious GPR40/FFAR1 Receptor Agonist

Early process development and salt selection for AMG 837, a novel GPR40 receptor agonist, is described. The synthetic route to AMG 837 involved the convergent synthesis and coupling of two key fragments, (S)-3-(4-hydroxyphenyl)hex-4-ynoic acid (1) and 3-(bromomethyl)-4′-(trifluoromethyl)biphenyl (2). The chiral β-alkynyl acid 1 was prepared in 35% overall yield via classical resolution of the corresponding racemic acid (±)-1. An efficient and scalable synthesis of (±)-1 was achieved via a telescoped sequence of reactions including the conjugate alkynylation of an in situ protected Meldrum’s acid derived acceptor prepared from 3. The biaryl bromide 2 was prepared in 86% yield via a 2-step Suzuki−Miyaura coupling−bromination sequence. Chemoselective phenol alkylation mediated by tetrabutylphosphonium hydroxide allowed direct coupling of 1 and 2 to afford AMG 837. Due to the poor physiochemical stability of the free acid form of the drug substance, a sodium salt form was selected for early development, and a more stable, crystalline hemicalcium salt dihydrate form was subsequently developed. Overall, the original 12-step synthesis of AMG 837 was replaced by a robust 9-step route affording the target in 25% yield.

2-(2-(1H-1,2,3-triazol-5-yl)ethoxy)-1-(2-((2,3-dihydro-1H-inden-2-yl)amino)-5,7-dihydro-6Hpyrrolo[3,4-d]pyrimidin-6-yl)ethan-1-one

l-[2-(2,3-dihydro- lH-inden-2-ylamino)-5,7-dihydro-6H-pyrrolo[3,4- d]pyrimidin-6-yl]-2-[2-(lH- l ,2,3-triazol-4-yl)ethoxy]ethanone.

US2014200231

Scheme A

Scheme B

Scheme C

VI

Scheme E

Autotaxin is an enzyme reported to be the source of lysophosphatidic acid (LPA) which up-regulates pain-related proteins through one if its cognate receptors, LPAi_. LPA is an intracellular lipid mediator which influences a multiplicity of biological and biochemical processes. Targeted inhibition of autotaxin-mediated LPA biosynthesis may provide a novel mechanism to prevent nerve injury-induced neuropathic pain.

Compounds that inhibit autotaxin are desired to offer a potential treatment option for patients in need of treatment for pain.

Pain associated with osteoarthritis (OA) is reported to be the primary symptom leading to lower extremity disability in OA patients. Over 20 million Americans have been diagnosed with OA, the most common of the arthropathies. The currently approved treatments for OA pain may be invasive, lose efficacy with long term use, and may not be appropriate for treating all patients. Additional treatment options for patients suffering from pain associated with OA are desired. Compounds that inhibit autotaxin represent another possible treatment option for patients with pain associated with OA.

U.S. Patent 7,524,852 (‘852) discloses substituted bicyclic pyrimidine derivatives as anti-inflammatory agents.

PCT/US2011/048477 discloses indole compounds as autotoxin inhibitors.

There is a need for novel compounds that provide autotaxin inhibition. The present invention provides novel compounds which are autotaxin inhibitors. The present invention provides certain novel compounds that inhibit the production of LPA.

Autotaxin inhibitor compounds are desired to provide treatments for autotaxin mediated conditions, such as pain and pain associated with OA.

PAPER

In an effort to develop a novel therapeutic agent aimed at addressing the unmet need of patients with osteoarthritis pain, we set out to develop an inhibitor for autotaxin with excellent potency and physical properties to allow for the clinical investigation of autotaxin-induced nociceptive and neuropathic pain. An initial hit identification campaign led to an aminopyrimidine series with an autotaxin IC₅₀ of 500 nM. X-ray crystallography enabled the optimization to a lead compound that demonstrated favorable potency (IC₅₀ = 2 nM), PK properties, and a robust PK/PD relationship.

Novel Autotaxin Inhibitors for the Treatment of Osteoarthritis Pain: Lead Optimization via Structure-Based Drug Design

http://pubs.acs.org/doi/abs/10.1021/acsmedchemlett.6b00207

Spencer Jones

2-(2-(1H-1,2,3-triazol-5-yl)ethoxy)-1-(2-((2,3-dihydro-1H-inden-2-yl)amino)-5,7-dihydro-6Hpyrrolo[3,4-d]pyrimidin-6-yl)ethan-1-one (9)

………… Purified the resulting residue by silica gel chromatography (gradient elution: 0-9% methanol in ethyl acetate ) to give the title compound……..

1H NMR (400 MHz, CDCl3): 60:40 mixure of rotamers * indicates minor rotamer δ 8.18 (bs, 0.6H), *8.13 (bs, 0.4H), 7.49 (s, 1H), 7.21-7.09 (m, 4 H), 5.70-5.50 (m, 1H), 4.87-4.78 (m, 1H), 4.75 (s, 1.2H), *4.67 (s, 0.8H), 4.64 (s, 1.2H) *4.53 (s, 0.8H), *4.30 (s, 0.8H), 4.28 (s, 1.2H), 3.93 (t, J = 5.6 Hz, 2H), 3.43 (dd, J = 16.2, 7.1 Hz, 2H), 3.10 (t, J = 5.6 Hz, 2H), 2.89 (dd, J = 16.2, 4.9 Hz, 2H).

13C NMR (400 MHz, CDCl3): * indicates minor δ *169.3, 16 169.2, 167.0, *166.8, *162.4, 162.2, 152.8, *152.3, 141.1, 137.8, 130.9, 126.7, 124.9, 115.9, 69.8, 69.3, *69.0, 52.7, *52.5, 51.2, 49.0, *47.9, 40.1, 24.7.

LC/MS (ESI+ ): (m/z) 406 (C21H24N7O2 = (M+1)+ ).

PATENT

WO-2014110000-A1

Example 2

Synthesis of l-[2-(2,3-dihydro- lH-inden-2-ylamino)-5,7-dihydro-6H-pyrrolo[3,4- d]pyrimidin-6-yl]-2-[2-(lH- l ,2,3-triazol-4-yl)ethoxy]ethanone.

Stir a mixture of 2-[2-(lH-triazol-5-yl)ethoxy]acetic acid 2,2,2-trifluoroacetic acid

(20.22 g; 70.90 mmol), N-(2,3-dihydro- lH-inden-2-yl)-6,7-dihydro-5H-pyrrolo[3,4- d]pyrimidin-2-amine dihydrochloride hydrate (27.99 g; 81.54 mmol) and triethylamine (98.83 mL; 709.03 mmol) in dimethylformamide (404.40 mL) at 0°C. Add a solution of 1-propanephosphonic acid cyclic anhydride (50% solution in DMF; 51.89 mL; 81.54 mmol) over 30 minutes, and stir the mixture at room temperature for 18 hours.

Concentrate the reaction mixture under reduced pressure to give a residue. Add water (200 mL) and extract the mixture with ethyl acetate (4 x 250 mL) and

dichloromethane (4 x 250 mL). Wash the combined organic layers with saturated aqueous sodium bicarbonate (2 x 100 mL) and brine (100 mL), then dry over anhydrous sodium sulfate. Filter the mixture and concentrate the solution under reduced pressure to give a red solid (25.70 g) that is slurried in ethyl acetate/methanol (9: 1 mixture; 200 mL) for 2 hours at room temperature. Filter the resulting solid and wash with cold ethyl acetate (50 mL) to give a solid (ca.18.2 g) that is re-slurried in ethyl acetate (200 mL) at reflux for 1 hour. On cooling to room temperature, stir the mixture for 1 hour and filter the resulting light pink solid.

Slurry the light pink solid in water/methanol (1 : 1 mixture; 200 mL) and heat the mixture at 50°C for 30 minutes. Add ammonium hydroxide solution (32% ; 50 mL) and continue to heat the mixture at 50°C for 30 minutes. Upon cooling to room temperature, add additional ammonium hydroxide solution (32% ; 50 mL) and continue stirring for 1 hour at room temperature. Filter the resulting light gray solid, dry and slurry again in ethyl acetate (200 mL) for 1 hour to afford a light gray solid that is filtered, washed with ethyl acetate (25 mL), and dried to give the title compound (12.42 g; 43%) as a gray solid. MS (m/z): 406 (M+l).

PATENT

US-20140200231-A1

https://www.google.com/patents/US20140200231

Scheme E

Preparation 7

Synthesis of 2-[2-(lH-triazol-5-yl)ethoxy]acetic acid.

Pressurize 1 atmosphere of hydrogen (g) to a flask containing [2-(l-benzyl-lH- l,2,3-triazol-5-yl)ethoxy]acetic acid (10.1 g; 1.00 equiv; 38.66 mmoles) and palladium (II) chloride (3 g; 16.92 mmoles; 3.00 g) in isopropyl alcohol (300 mL) and water (60 mL). Maintain the flask under a hydrogen atmosphere for 3 h, then filter through Celite™ and concentrate. Add toluene (2×50 mL) and concentrate to afford the title compound (7.96 g, 100%). ^]H NMR (d₆-DMSO): 2.86 (t, / = 7 Hz, 2 H), 3.65 (t, / = 7 Hz, 2 H), 3.98 (s, 2 H), 7,77 (s, 1 H), 13.4 – 13.6 (br s, 2 H).

Example 1

Synthesis of l-[2-(2,3-dihydro-lH-inden-2-ylamino)-7,8-dihydropyrido[4,3-d]pyrimidin- 6(5H)-yl]-2-[2-(lH-l,2,3-triazol-4- l)ethoxy]ethanone.

Add N-indan-2-yl-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-2-amine (4.2 g, 15.8 mmol) to a mixture of 2-[2-(lH-triazol-5-yl)ethoxy]acetic acid (2.7 g, 15.8 mmol), 1-hydroxybenzotriazole (3.20 g, 23.7 mmol), and dimethylaminopropyl)-3- ethylcarbodiimide hydrochloride (5.44 g, 28.4 mmol) in dichloromethane (40 mL) at 25 °C. Add triethylamine (4.40 mL, 31.6 mmol) to the reaction mixture and stir for 16 h. Wash with water (2 x 50 mL) and concentrate the organic layer. Purify by silica gel column chromatography, eluting with ethyl acetate/methanol, to give the title compound (4.0 g, 60%) as a solid. MS (m/z): 420 (M + Η). Preparation 8

Synthesis of 2-chloro-l-[2-(2,3-dihydro-lH-inden-2-ylamino)-7,8-dihydropyrido[4,3- d]pyrimidin-6(5H)-yl]ethanone.

To N-indan-2-yl-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-2-amine (11.0 g, 41.3 mmol) and triethylamine (7.48 mL, 53.7 mmol) in dichloromethane (200 mL), add 2- chloroacetyl chloride (3.61 mL, 5.13 g, 45.4 mmol) dropwise over five minutes at 23 °C. Stir for 30 minutes and pour the reaction mixture into 1 : 1 50% saturated aqueous sodium bicarbonate: dichloromethane (75 mL). Separate the organic layer from the aqueous layer and further extract the aqueous layer with dichloromethane (2 x 25 mL). Combine the organic extracts and dry over anhydrous sodium sulfate, filter, and concentrate. Dissolve the residue in chloroform (10 mL) and purify via silica gel column chromatography (gradient elution: 25% ethyl acetate in hexanes to 100% ethyl acetate) to give the title compound (9.75 g, 69%). ^]H NMR (CDC1₃, * = minor amide rotamer) δ 2.77* (t, 2H), 2.84 (dd, 2H), 2.87 (t, 2H), 3.35 (dd, 2H), 3.76 (t, 2H), 3.85* (t, 2H), 4.12 (s, 2H), 4.52* (s, 2H), 4.57 (s, 2H), 4.72-4.82 (m, IH), 5.48-5.64 (m, IH), 7.12-7.21 (m, 4H), 8.03-8.10 (m, IH).

Preparation 9

Synthesis of 2-(but-3-yn-l-yloxy)-l-[2-(2,3-dihydro-lH-inden-2-ylamino)-7,8- dihydropyrido[4,3-d]p rimidin-6(5H)-yl]ethanone.

To sodium hydride (60 wt% in mineral oil, 1.58 g, 39.6 mmol) in tetrahydrofuran (50 mL) at 23 °C, add 3-butyn-l-ol (7.93 g, 8.59 mL, 113.2 mmol) dropwise, then stir at 23 °C for 20 minutes. Add this solution to 2-chloro-l-[2-(2,3-dihydro-lH-inden-2- ylamino)-7,8-dihydropyrido[4,3-d]pyrimidin-6(5H)-yl]ethanone (9.70 g, 28.3 mmol) in tetrahydrofuran (150 mL) at 23 °C and stir for one hour. Pour the reaction mixture into 50% saturated aqueous sodium bicarbonate solution. Separate the organic layer and further extract the aqueous layer with ethyl ether (x 2) and ethyl acetate (x 2). Combine the organic extracts and wash with brine, then dry over anhydrous sodium sulfate, filter, and concentrate. Purify the resulting crude product by silica gel column chromatography (gradient elution: 20% ethyl acetate in hexanes to 100% ethyl acetate) to give the title compound (8.16 g, 77%). MS (m/z): 377 (M + 1).

Example la

Alternative synthesis of l-[2-(2,3-dihydro- lH-inden-2-ylamino)-7,8-dihydropyrido[4,3- d]pyrimidin-6(5H)-yl]-2-[2-(lH- l,2,3-triazol-4- l)ethoxy]ethanone.

Sparge a solution of 2-(but-3-yn- l-yloxy)-l-[2-(2,3-dihydro-lH-inden-2- ylamino)-7,8-dihydropyrido[4,3-d]pyrimidin-6(5H)-yl]ethanone (8.15 g, 21.7 mmol) and L-ascorbic acid sodium salt (8.58 g, 43.3 mmol) in dimethylformamide (60 mL) and water (60 mL) with nitrogen for ten minutes, then evacuate and backfill with nitrogen three times. Add copper (II) sulfate pentahydrate (1.08 g, 4.33 mmol) and heat to 90 °C, then add azidotrimethylsilane (23.1 mL, 20.0 g, 173 mmol) dropwise and stir for one hour. Cool reaction mixture to 23 °C and pour into water (50 mL). Extract this mixture with ethyl acetate (4 x 50 mL). Combine the organic extracts and wash with saturated aqueous sodium chloride, dry over anhydrous sodium sulfate, filter, and concentrate.

Purify the resulting crude product by silica gel column chromatography (gradient elution: 0 to 10% methanol in ethyl acetate) to give the title compound (3.60 g, 40%). MS (m/z): 420 (M + 1). Preparation 10

Synthesis of tert-butyl-2-(2,3-dihydro-lH-inden-2-ylamino)-5,7-dihydro-6H-pyrrolo[3,4- d]pyrimidine-6-carboxylate.

Charge 450 rriL (2.58 mol) of N-ethyl-N-isopropylpropan-2-amine into a 15 °C solution of tert-butyl 2-chloro-5,7-dihydro-6H-pyrrolo[3,4-d]pyrimidine-6-carboxylate (220 g, 860.37 mmol) and 2,3-dihydro-lH-inden-2-amine (137.7 g, 1.03 mol) in 1- methylpyrrolidin-2-one (3.6 L). Heat the resulting mixture to 80 °C for 16 h, then cool to 30 °C and transfer the resulting mixture into 5 L of water at 25 °C. Filter the resulting solid and rinse the filter cake with water (2 x 300 rriL). Reslurry the solid in ethyl acetate (350 iriL) for 45 min at 15 °C. Filter the slurry, rinsing with 15 °C ethyl acetate ( 2 x 250 rriL), and dry to give the title compound (226 g, 75%) as an off-white solid. ‘H NMR (d₆-DMSO) 1.45 (s, 9 H), 2.87 (dd, /= 7.2, 15.8 Hz, 2 H), 3.24 (dd, /= 7.2, 15.8 Hz, 2 H), 4.36 (d, 10.4 Hz, 2 H), 4.44 (d, /= 12.8 Hz, 2 H), 4.60 (m, 1 H), 7.14 (m, 2 H), 7.20 (m, 2 H), 7.55 (d, /= 6.8 Hz, 1 H), 8.27 (d, /= 7.2 Hz, 1 H).

Preparation 11

Synthesis of N-(2,3-dihydro-lH-inden-2-yl)-6,7-dihydro-5H-pyrrolo[3,4-d]pyrimidin-2- amine dihydrochloride hydrate.

Charge 670 rriL of 5 M hydrochloric acid (3.35 mol) to a solution of tert-butyl 2-

(2,3-dihydro-lH-inden-2-ylamino)-5,7-dihydro-6H pyrrolo[3,4-d]pyrimidine-6- carboxylate (226 g, 641.25 mmol) in tetrahydrofuran (2.0 L) at 17 °C, maintaining the internal temperature below 26 °C during the addition. Heat the resulting solution to 50 °C for 16 h, cool to 25 °C and dilute with 500 rriL of water and 500 mL of tert- butylmethylether. Separate the resulting layers and extract with tert-butylmethylether (3 x 1 L). Concentrate the water phase down to a reaction volume of ca. 200 mL, and filter the resulting slurry. Rinse the cake with tert-butylmethylether (2 x 200 mL) and dry to give the title product (177 g, 80%) as a light brown solid. MS (m/z): 253.2 (M-2HC1- H₂0+1).

Preparation 12

Syntheis of tert-butyl 2-but-3-ynox acetate.

Stir a mixture of but-3-yn-l-ol (6.00 g; 85.60 mmol), tetrabutylammonium sulfate (2.07 g; 8.54 mmol) and sodium hydroxide (40% wt/wt; 150 mL) in dichloromethane (150 mL) at 0°C. Add tert-butyl bromoacetate (19.34 mL; 128.40 mmol) dropwise and stir the mixture for 2.5 hours at room temperature. Dilute the reaction mixture with dichloromethane (200 mL) and water (100 mL), separate the layers, and further extract the aqueous layer with dichloromethane (2 x 100 mL). Wash the combined organic layers with brine (100 mL), dry over anhydrous sodium sulfate, and concentrate to afford the crude title compound as a brown oil (11.93 g). Purify the oil by silica gel column chromatography, eluting with hexane: ethyl acetate (0% to 10% mixtures) to give the title compound (11.35 g; 72%) as a colorless oil. ^]H NMR (CDCI₃) δ 1.48 (s, 9H), 2.00 (m, 1H), 2.52 (m, 2H), 3.67 (m, 2H), 4.01 (bs, 2H).

Preparation 13

Synthesis of tert-butyl 2-[2-(lH-triazol-5- l)ethoxy]acetate.

Stir tert-Butyl 2-but-3-ynoxyacetate (11.34 g; 61.55 mmol) and copper(I)iodide (584 mg; 3.07 mmol) in a mixture of dimethylformamide (56.70 mL) and methanol (11.34 mL) at 0°C. Add azido(trimethyl)silane (12.33 mL; 86.47 mmol) dropwise and heat the mixture at 90°C for 18 hours.

In a second batch, stir tert-butyl 2-but-3-ynoxyacetate (4.38 g; 23.77 mmol) and copper(I)iodide (226 mg; 1.19 mmol) in a mixture of dimethylformamide (22 mL) and methanol (6 mL) at 0°C. Add azido(trimethyl)silane (4.8 mL; 33.66 mmol) dropwise and the mixture heated at 90°C for 18 hours.

Upon cooling to room temperature, combine the crude products from both batches and concentrate the mixture to afford a greenish residue. Purify the crude product by filtration through a plug of silica eluting with dichloromethane: ethyl acetate (75% to 100% mixtures) to afford the title compound (14.15 g, 73%) as a colorless oil. MS (m/z): 228.15 (M+l).

Preparation 14

Synthesis of 2-[2-(lH-triazol-5-yl)ethoxy]acetic acid 2,2,2-trifluoroacetic acid.

Stir a mixture of ieri-butyl 2-[2-(lH-triazol-5-yl)ethoxy]acetate (14.15 g; 62.26 mmol) and trifluoroacetic acid (70.75 mL, 935.69 mmol) in dichloromethane (70.75 mL) for 2 hours at room temperature. Concentrate the reaction mixture under reduced pressure to provide the title compound containing additional trifluoroacetic acid (20.22 g, >100%) as a brown solid. MS (m/z): 172.05 (M+l).

Example 2

Synthesis of l-[2-(2,3-dihydro- lH-inden-2-ylamino)-5,7-dihydro-6H-pyrrolo[3,4- d]pyrimidin-6-yl]-2-[2-(lH- l ,2,3-triazol-4-yl)ethoxy]ethanone.

Stir a mixture of 2-[2-(lH-triazol-5-yl)ethoxy]acetic acid 2,2,2-trifluoroacetic acid

(20.22 g; 70.90 mmol), N-(2,3-dihydro- lH-inden-2-yl)-6,7-dihydro-5H-pyrrolo[3,4- d]pyrimidin-2-amine dihydrochloride hydrate (27.99 g; 81.54 mmol) and triethylamine (98.83 mL; 709.03 mmol) in dimethylformamide (404.40 mL) at 0°C. Add a solution of 1-propanephosphonic acid cyclic anhydride (50% solution in DMF; 51.89 mL; 81.54 mmol) over 30 minutes, and stir the mixture at room temperature for 18 hours.

Concentrate the reaction mixture under reduced pressure to give a residue. Add water (200 mL) and extract the mixture with ethyl acetate (4 x 250 mL) and

dichloromethane (4 x 250 mL). Wash the combined organic layers with saturated aqueous sodium bicarbonate (2 x 100 mL) and brine (100 mL), then dry over anhydrous sodium sulfate. Filter the mixture and concentrate the solution under reduced pressure to give a red solid (25.70 g) that is slurried in ethyl acetate/methanol (9: 1 mixture; 200 mL) for 2 hours at room temperature. Filter the resulting solid and wash with cold ethyl acetate (50 mL) to give a solid (ca.18.2 g) that is re-slurried in ethyl acetate (200 mL) at reflux for 1 hour. On cooling to room temperature, stir the mixture for 1 hour and filter the resulting light pink solid.

Slurry the light pink solid in water/methanol (1 : 1 mixture; 200 mL) and heat the mixture at 50°C for 30 minutes. Add ammonium hydroxide solution (32% ; 50 mL) and continue to heat the mixture at 50°C for 30 minutes. Upon cooling to room temperature, add additional ammonium hydroxide solution (32% ; 50 mL) and continue stirring for 1 hour at room temperature. Filter the resulting light gray solid, dry and slurry again in ethyl acetate (200 mL) for 1 hour to afford a light gray solid that is filtered, washed with ethyl acetate (25 mL), and dried to give the title compound (12.42 g; 43%) as a gray solid. MS (m/z): 406 (M+l).

Preparation 15

Synthesis of 2-chloro- l-[2-(2,3-dihydro- lH-inden-2-ylamino)-5,7-dihydro-6H- pyrrolo[3,4-d]pyrimidin-6-yl]ethanone.

Stir a suspension of N-(2,3-dihydro-lH-inden-2-yl)-6,7-dihydro-5H-pyrrolo[3,4- d]pyrimidin-2-amine dihydrochloride hydrate (14.4 g, 41.9 mmol) and triethylamine (14.3 g, 19.7 mL, 141.4 mmol) in dichloromethane (200 mL) at 23 °C for 10 minutes, then cool to -30 °C. Add 2-chloroacetyl chloride (5.49 g, 3.86 mL, 48.6 mmol) over two minutes and warm to 23 °C over 10 minutes. Add methanol (5 mL) and remove the solvent in vacuo. Slurry the crude reaction mixture in methanol (30 mL), add 50 g silica gel and remove solvent in vacuo. Load the resulting residue onto a loading column and purify via silica gel column chromatography (gradient elution: 50% ethyl acetate in hexanes to ethyl acetate to 10% methanol in ethyl acetate) to give the title compound (11.5 g, 84%). MS (m/z): 329(M+1).

Preparation 16

Synthesis of 2-(but-3-yn-l-yloxy)-l-[2-(2,3-dihydro-lH-inden-2-ylamino)-5,7-dihydro- 6H-pyrrolo[3,4-d]pyrimidin-6-yl]ethanone.

To sodium hydride (60 wt% in mineral oil, 2.06 g, 51.4 mmol) in tetrahydrofuran (86 mL) at 0 °C, add 3-butyn-l-ol (4.64 g, 5.03 mL, 64.3 mmol), then stir at 23 °C for 15 minutes. Add this solution to 2-chloro-l-[2-(2,3-dihydro-lH-inden-2-ylamino)-5,7- dihydro-6H-pyrrolo[3,4-d]pyrimidin-6-yl]ethanone (8.45 g, 25.7 mmol) in

tetrahydrofuran (86 mL) at 0 °C and stir for five minutes. Pour reaction mixture into 50% saturated aqueous sodium bicarbonate solution. Separate the organic layer and further extract the aqueous layer with ethyl ether and ethyl acetate (2 x 50 mL each). Combine the organic extracts and wash with brine, then dry over anhydrous sodium sulfate, filter, and concentrate. Combine the crude product with the crude product from a second reaction (run reaction under identical conditions and stoichiometry employing 2-chloro- 1- [2-(indan-2-ylamino)-5,7-dihydropyrrolo[3,4-d]pyrimidin-6-yl]ethanone (3.0 g, 9.1 mmol)) and purify by silica gel column chromatography (gradient elution: 25% ethyl acetate in hexanes to 100% ethyl acetate) to give the title compound (2.90 g, 23%). MS

(m/z): 363(M+1). Example 2a

Alternative synthesis of l-[2-(2,3-dihydro-lH-inden-2-ylamino)-5,7-dihydro- pyrrolo[3,4-d]pyrimidin-6-yl]-2-[2-(lH-l,2,3-triazol-4-yl)ethoxy]ethanone.

Add dimethylformamide (27 mL) and water (27 mL) to a flask containing 2-(but- 3-yn-l-yloxy)-l-[2-(2,3-dihydro-lH-inden-2-ylamino)-5,7-dihydro-6H-pyrrolo[3,4- d]pyrimidin-6-yl]ethanone (2.90 g, 8.00 mmol). Add copper (II) sulfate pentahydrate (400 mg, 1.60 mmol) and L-ascorbic acid sodium salt (3.17 g, 16.0 mmol). Evacuate flask and backfill with nitrogen (x 2), then add azidotrimethylsilane (7.37 g, 8.53 mL, 64.0 mmol) and heat the reaction to 90 °C for 70 minutes. Cool the reaction mixture to 23 °C and remove all solvent in vacuo. Suspend the residue in methanol/dichloromethane and then add silica gel and remove solvent in vacuo. Load this material onto a loading column and purify via silica gel column chromatography (gradient elution: 0-9% methanol in ethyl acetate) to give the title compound (980 mg, 30%). MS (m/z):

406(M+1).

/////////Autotaxin,  LPA,  osteoarthritis,  tool molecule, lily, Spencer Jones, PRECLINICAL

N1(Cc2cnc(nc2C1)NC3Cc4ccccc4C3)C(=O)COCCc5cnnn5

(From left to right) Principal Investigator Associate Professor Gautam Sethi and NUS PhD candidate Ms Zhang Jingwen from the Department of Pharmacology at the NUS Yong Loo Lin School of Medicine led a research which found that a bioactive compound from the neem plant could significantly suppress development of prostate cancer.

Credit: National University of Singapore

Date:September 29, 2016Source:National University of SingaporeSummary:Oral administration of nimbolide, over 12 weeks shows reduction of prostate tumor size by up to 70 per cent and decrease in tumor metastasis by up to 50 per cent, report investigators.

Nimbolide; NSC309909; NSC 309909; Methyl[8-(furan-3-yl)-2a,5a,6a,7-tetramethyl-2,5-dioxo-2a,5a,6,6a,8,9,9a,10a,10b,10c-decahydro-2h,5h-cyclopenta[d]naphtho[2,3-b:1,8-b’c’]difuran-6-yl]acetate; CCRIS 5723;

Oral administration of nimbolide, over 12 weeks shows reduction of prostate tumor size by up to 70 per cent and decrease in tumor metastasis by up to 50 per cent

A team of international researchers led by Associate Professor Gautam Sethi from the Department of Pharmacology at the Yong Loo Lin School of Medicine at the National University of Singapore (NUS) has found that nimbolide, a bioactive terpenoid compound derived from Azadirachta indica or more commonly known as the neem plant, could reduce the size of prostate tumor by up to 70 per cent and suppress its spread or metastasis by half.

Prostate cancer is one of the most commonly diagnosed cancers worldwide. However, currently available therapies for metastatic prostate cancer are only marginally effective. Hence, there is a need for more novel treatment alternatives and options.

“Although the diverse anti-cancer effects of nimbolide have been reported in different cancer types, its potential effects on prostate cancer initiation and progression have not been demonstrated in scientific studies. In this research, we have demonstrated that nimbolide can inhibit tumor cell viability — a cellular process that directly affects the ability of a cell to proliferate, grow, divide, or repair damaged cell components — and induce programmed cell death in prostate cancer cells,” said Assoc Prof Sethi.

Nimbolide: promising effects on prostate cancer

Cell invasion and migration are key steps during tumor metastasis. The NUS-led study revealed that nimbolide can significantly suppress cell invasion and migration of prostate cancer cells, suggesting its ability to reduce tumor metastasis.

The researchers observed that upon the 12 weeks of administering nimbolide, the size of prostate cancer tumor was reduced by as much as 70 per cent and its metastasis decreased by about 50 per cent, without exhibiting any significant adverse effects.

“This is possible because a direct target of nimbolide in prostate cancer is glutathione reductase, an enzyme which is responsible for maintaining the antioxidant system that regulates the STAT3 gene in the body. The activation of the STAT3 gene has been reported to contribute to prostate tumor growth and metastasis,” explained Assoc Prof Sethi. “We have found that nimbolide can substantially inhibit STAT3 activation and thereby abrogating the growth and metastasis of prostate tumor,” he added.

The findings of the study were published in the April 2016 issue of the scientific journal Antioxidants & Redox Signaling. This work was carried out in collaboration with Professor Goh Boon Cher of Cancer Science Institute of Singapore at NUS, Professor Hui Kam Man of National Cancer Centre Singapore and Professor Ahn Kwang Seok of Kyung Hee University.

Neem — The medicinal plant

The neem plant belongs to the mahogany tree family that is originally native to India and the Indian sub-continent. It has been part of traditional Asian medicine for centuries and is typically used in Indian Ayurvedic medicine. Today, neem leaves and bark have been incorporated into many personal care products such as soaps, toothpaste, skincare and even dietary supplements.

Future Research

The team is looking to embark on a genome-wide screening or to perform a large-scale study of proteins to analyse the side-effects and determine other potential molecular targets of nimbolide. They are also keen to investigate the efficacy of combinatory regimen of nimbolide and approved drugs such as docetaxel and enzalutamide for future prostate cancer therapy.

Journal Reference:

1. Jingwen Zhang, Kwang Seok Ahn, Chulwon Kim, Muthu K. Shanmugam, Kodappully Sivaraman Siveen, Frank Arfuso, Ramar Perumal Samym, Amudha Deivasigamanim, Lina Hsiu Kim Lim, Lingzhi Wang, Boon Cher Goh, Alan Prem Kumar, Kam Man Hui, Gautam Sethi. Nimbolide-Induced Oxidative Stress Abrogates STAT3 Signaling Cascade and Inhibits Tumor Growth in Transgenic Adenocarcinoma of Mouse Prostate Model. Antioxidants & Redox Signaling, 2016; 24 (11): 575 DOI:10.1089/ars.2015.6418

A PAPER

NIMBOLIDE 1

http://pubs.rsc.org/en/content/articlelanding/2015/ra/c5ra16071e#!divAbstract

Nimbolide (1): Pale yellow crystals; C27H30O7;

FT-IR (KBr, υmax, cm -1): 2978, 1778, 1730, 1672, 1433, 1296, 1238, 1192, 1153, 1069, 951, 827, 750;

1H NMR (500 MHz, CDCl3) δH: 7.32 (t, J = 1.5 Hz, 1H), 7.28 (d, J = 9.5 Hz, 1H), 7.22 (s, 1H), 6.25 (m, 1H), 5.93 (d, J = 10.0 Hz, 1H), 5.53 (m, 1H), 4.62 (dd, J = 3.67 Hz, 12 .5 Hz, 1H), 4.27 (d, J = 3.5 Hz, 1H), 3.67 (d, J = 9.0 Hz, 1H), 3.54 (s, 3H), 3.25 (dd, J = 5.0 Hz, 16.25 Hz, 1H), 3.19 (d, J = 12.5 Hz, 1H), 2.73 (t, J = 5.5 Hz, 1H), 2.38 (dd, J = 5.5 Hz, 16.25 Hz, 1H), 2.22 (dd, J = 6.5 Hz, 12.0 Hz, 1H), 2.10 (m, 1H), 1.70 (s, 3H), 1.47 (s, 3H), 1.37 (s, 3H), 1.22 (s, 3H);

13C NMR (125 MHz, CDCl3) δC: 200.8 (CO), 175.0 (COO), 173.0 (COO), 149.6 (CH), 144.8 (C), 143.2 (CH), 138.9 (CH), 136.4 (C), 131.0 (CH), 126.5 (C), 110.3 (CH), 88.5 (CH), 82.9 (CH), 73.4 (CH), 51.8 (OCH3), 50.3 (C), 49.5 (CH), 47.7 (CH), 45.3 (C), 43.7 (C), 41.2 (CH2), 41.1 (CH), 32.1 (CH2), 18.5 (CH3), 17.2 (CH3), 15.2 (CH3), 12.9 (CH3);

HR-MS (m/z): 467.20795 [(M+H)+ ].

Content Page No 1 1H NMR spectrum of nimbolide S1 2 13C NMR spectrum of nimbolide S2 3 Mass spectrum of nimbolide

Academic Qualifications
BSc. Chem. (Hons)	1998	Banaras Hindu University, Varanasi, India.
MSc. Biochemistry	2000	Banaras Hindu University, Varanasi, India.
Ph.D. Biotechnology	2004	Banaras Hindu University, Varanasi, India.
Appointments to Date
Assistant Professor	2008-date	Department of Pharmacology, National University of Singapore, Singapore
Postdoctoral Fellow	2004-2007	Department of Experimental Therapeutics, The University of Texas. MD Anderson Cancer Center, Houston TX USA.
Senior Research Fellow	2002-2004	(CSIR-NET) at School of Biotechnology, Banaras Hindu University, Varanasi, India.
Junior Research Fellow	2000-2002	(CSIR-NET) at School of Biotechnology, Banaras Hindu University, Varanasi, India.
Honours and Awards
2007	Ramalingaswamy fellowship from Department of Biotechnology, Government of India for outstanding research contributions in the field of Cancer Biology.
2002	Senior Research Fellowship award, Council of Scientific and Industrial Research, New Delhi, India.
2000	Junior Research Fellowship award, Council of Scientific and Industrial Research, New Delhi, India.
Research Interests
Selected Publications
Reviews and Book Chapters

/////////NIMBOLIDE, CANCER, NEEM, PROSTRATE, National University of Singapore, Gautam Sethi

CC1=C2C(CC1C3=COC=C3)OC4C2(C(C5(C6C4OC(=O)C6(C=CC5=O)C)C)CC(=O)OC)C

GNE-272

(S)-1-(3-((2-fluoro-4-(1-methyl-1H-pyrazol-4- yl)phenyl)amino)-1-(tetrahydrofuran-3-yl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridin- 5(4H)-yl)ethanone

1-[3-[2-fluoro-4-(1-methylpyrazol-4-yl)anilino]-1-[(3S)-oxolan-3-yl]-6,7-dihydro-4H-pyrazolo[4,3-c]pyridin-5-yl]ethanone

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ROMERO, F. Anthony; (US).
MAGNUSON, Steven; (US).
PASTOR, Richard; (US).
TSUI, Vickie Hsiao-Wei; (US).
MURRAY, Jeremy; (US).
CRAWFORD, Terry; (US).
ALBRECHT, Brian, K.; (US).
COTE, Alexandre; (US).
TAYLOR, Alexander, M.; (US).
LAI, Kwong Wah; (CN).
CHEN, Kevin, X.; (CN).
BRONNER, Sarah; (US).
ADLER, Marc; (US).
EGEN, Jackson; (US).
LIAO, Jiangpeng; (CN).
WANG, Fei; (CN).
CYR, Patrick; (US).
ZHU, Bing-Yan; (US).
KAUDER, Steven; (US)

Chromatin is a complex combination of DNA and protein that makes up chromosomes. It is found inside the nuclei of eukaryotic cells and is divided between heterochromatin (condensed) and euchromatin (extended) forms. The major components of chromatin are DNA and proteins. Histones are the chief protein components of chromatin, acting as spools around which DNA winds. The functions of chromatin are to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis, and to serve as a mechanism to control expression and DNA replication. The chromatin structure is controlled by a series of post-translational modifications to histone proteins, notably histones H3 and H4, and most commonly within the “histone tails” which extend beyond the core nucleosome structure. Histone tails tend to be free for protein-protein interaction and are also the portion of the histone most prone to post-translational modification. These modifications include acetylation, methylation, phosphorylation, ubiquitinylation, and SUMOylation. These epigenetic marks are written and erased by specific enzymes that place the tags on specific residues within the histone tail, thereby forming an epigenetic code, which is then interpreted by the cell to allow gene specific regulation of chromatin structure and thereby transcription.

Of all classes of proteins, histones are amongst the most susceptible to post-translational modification. Histone modifications are dynamic, as they can be added or removed in response to specific stimuli, and these modifications direct both structural changes to chromatin and alterations in gene transcription. Distinct classes of enzymes, namely histone acetyltransferases (HATs) and histone deacetylases (HDACs), acetylate or de-acetylate specific histone lysine residues (Struhl K., Genes Dev., 1989, 12, 5, 599-606).

Bromodomains, which are approximately 1 10 amino acids long, are found in a large number of chromatin-associated proteins and have been identified in approximately 70 human proteins, often adjacent to other protein motifs (Jeanmougin F., et al., Trends Biochem. Sc , 1997, 22, 5, 151-153; and Tamkun J.W., et al., Cell, 1992, 7, 3, 561-572).

Interactions between bromodomains and modified histones may be an important mechanism underlying chromatin structural changes and gene regulation. Bromodomain-containing proteins have been implicated in disease processes including cancer, inflammation and viral replication. See, e.g., Prinjha et al,, Trends Pharm. Sci., 33(3):146-153 (2012) and Muller et al , Expert Rev. , 13 (29): 1 -20 (September 201 1 ).

Cell-type specificity and proper tissue functionality requires the tight control of distinct transcriptional programs that are intimately influenced by their environment.

Alterations to this transcriptional homeostasis are directly associated with numerous disease states, most notably cancer, immuno-inflammation, neurological disorders, and metabolic diseases. Bromodomains reside within key chromatin modifying complexes that serve to control distinctive disease-associated transcriptional pathways. This is highlighted by the observation that mutations in bromodomain-containing proteins are linked to cancer, as well as immune and neurologic dysfunction. Hence, the selective inhibition of bromodomains across a specific family, such as the selective inhibition of a bromodomain of CBP/EP300, creates varied opportunities as novel therapeutic agents in human dysfunction.

There is a need for treatments for cancer, immunological disorders, and other

CBP/EP300 bromodomain related diseases.

PATENT

WO-2016086200

Scheme 1

Scheme 2

Scheme 3

Scheme 4

General procedure for Intermediates A & B

Intermediate A

Intermediate

General procedure for Intermediates F & G

Intermediate F

Intermediate G

Step 1:

(R)-tetrahydrofuran-3-yI methanesulfonate

To a solution of (^)-tetrahydrofuran-3-ol (25 g, 253.7 mmol) in DCM (250 mL) at 0 °C was added triethylamine (86 g, 851.2 mmol) and mesyl chloride (39 g, 340.48 mmol) dropwise. The mixture was stirred at room temperature for 12 h. The reaction was quenched with water (100 mL) and extracted with DCM (100 mL x 2). The combined organic layers were dried over anhydrous Na₂S0₄, filtered and concentrated in vacuo to give the title compound (47 g, 99%) as a brown oil. Ή NMR (400 MHz, CDC1₃) δ 5.35 – 5.27 (m, 1H), 4.05 – 3.83 (m, 4H), 3.04 (s, 3 H), 2.28 – 2.20 (m, 2 H).

Step 2:

(S)-tert-butyl 3-bromo-l-(tetrahydrofuran-3-yI)-6,7-dihydro-li/-pyrazolo[43- c] pyridine-5(4H)-carboxylate

To a solution of tert-butyl 3-bromo-6,7-dihydro-lH-pyrazolo[4,3-c]pyridine-5(4H)-carboxylate (Intermediate A, 24.8 g, 82 mmol) in DMF (200 mL) was added Cs₂C0₃ (79 g, 246 mmol) and (/?)-tetrahydrofuran-3-yl methanesulfonate (17.4 g, 98 mmol). The mixture was heated to 80 °C for 12 h. After cooling the reaction to room temperature, the mixture was concentrated in vacuo. The crude residue was purified by silica gel chromatography

(petroleum ether / EtOAc = from 10 : 1 to 3 : 1) to give the title compound (Intermediate F, 50 g, 71 %) as a yellow oil. Ή NMR (400 MHz, DMSO-i ) δ 4.97 – 4.78 (m, 1H), 4.13 (s, 2H), 3.98 – 3.86 (m, 2H), 3.81 – 3.67 (m, 2H), 3.56 (t, J= 5.6 Hz, 2H), 2.68 (t, J= 5.6 Hz, 2H), 2.33 – 2.08 (m, 2H), 1.38 (s, 9H).

Step 3:

(5)-l-(3-bromo-l-(tetrahydrofuran-3-yl)-6,7-dihydro-lH-pyrazoIo[4,3-c]pyridin-5(4//)- yl)ethanone

To a solution of (S)-tert-buty\ 3-bromo- 1 -(tetrahydrofuran-3-yl)-6,7-dihydro-lH-pyrazolo [4,3 -c]pyridine-5(4H)-carboxy late (29 g, 78 mmol) in DCM (300 mL) was added trifluroacetic acid (70 mL) dropwise. The mixture was stirred at room temperature for 2 h. The solvent was concentrated in vacuo and the crude residue was re -dissolved in DMF (100 mL). The mixture was cooled to 0 °C before triethylamine (30 g, 156 mmol) and acetic anhydride (8.7 g, 86 mmol) were added dropwise. The mixture was stirred at room temperature for an additional 2 h. The reaction was quenched with water (200 mL) at 0 °C and extracted with EtOAc (150 mL x 3). The combined organic layers were dried over anhydrous Na₂S0 , filtered and concentrated in vacuo. The crude residue was purified by silica gel chromatography (DCM / MeOH = 30 : 1) to give the title compound (Intermediate G, 21.3 g, 87%) as a white solid. ^lH NMR (400 MHz, CDC1₃) δ 4.78 – 4.67 (m, 1H), 4.45 -4.29 (m, 2H), 4.15 – 4.06 (m, 2H), 3.96 – 3.92 (m, 2H), 3.88 – 3.70 (m, 2H), 2.71 – 2.67 (m, 2H), 2.38 – 2.34 (m, 2H), 2.16 (s, 3H).

PATENT

US-20160158207

Example 300

1-[3-[2-fluoro-4-(1-methylpyrazol-4- yl)anilino]-1-[(3S)-tetrahydrofuran-3- yl]-6,7-dihydro-4H-pyrazolo[4,3- c]pyridin-5-yl]ethanone

1H NMR (400 MHz, DMSO- d6) δ 8.03 (s, 1H), 7.83-7.68 (m, 3H), 7.36-7.33 (m, 1H), 7.32-7.21 (m, 1H), 4.88- 4.84 (m, 1H), 4.40-4.33 (m, 2H), 4.03-3.99 (m, 2H), 3.84- 3.67 (m, 7H), 2.79-2.64 (m, 2H), 2.26-2.21 (m, 2H), 2.08-2.05 (m, 3H)

425

General Procedure for Intermediates F & G

Step 1

(R)-tetrahydrofuran-3-yl methanesulfonate

Step 2

(S)-tert-butyl 3-bromo-1-(tetrahydrofuran-3-yl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridine-5(4H)-carboxylate

Step 3

(S)-1-(3-bromo-1-(tetrahydrofuran-3-yl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridin-5(4H)-yl)ethanone

OTHER ISOMER

Example 299

1-[3-[2-fluoro-4-(1-methylpyrazol-4- yl)anilino]-1-[(3R)-tetrahydrofuran-3- yl]-6,7-dihydro-4H-pyrazolo[4,3- c]pyridin-5-yl]ethanone

1H NMR (400 MHz, DMSO- d6) δ 8.03 (s, 1H), 7.83-7.67 (m, 3H), 7.39-7.34 (m, 1H), 7.26-7.21 (m, 1H), 4.87- 4.77 (m, 1H), 4.41-4.34 (m, 2H), 4.02-3.97 (m, 2H), 3.83 (s, 3H), 3.81-3.67 (m, 4H), 2.77-2.66 (m, 2H), 2.26- 2.22 (m, 2H), 2.08-2.05 (m, 3H)

425

PAPER

The single bromodomain of the closely related transcriptional regulators CBP/EP300 is a target of much recent interest in cancer and immune system regulation. A co-crystal structure of a ligand-efficient screening hit and the CBP bromodomain guided initial design targeting the LPF shelf, ZA loop, and acetylated lysine binding regions. Structure–activity relationship studies allowed us to identify a more potent analogue. Optimization of permeability and microsomal stability and subsequent improvement of mouse hepatocyte stability afforded 59 (GNE-272, TR-FRET IC₅₀ = 0.02 μM, BRET IC₅₀ = 0.41 μM, BRD4(1) IC₅₀ = 13 μM) that retained the best balance of cell potency, selectivity, and in vivo PK. Compound 59 showed a marked antiproliferative effect in hematologic cancer cell lines and modulates MYC expression in vivo that corresponds with antitumor activity in an AML tumor model.

Discovery of a Potent and Selective in Vivo Probe (GNE-272) for the Bromodomains of CBP/EP300

UNDESIRED R ISOMER

In a similar procedure to59, the title compound was prepared from (S)-tetrahydrofuran-3-yl
methanesulfonate and purified by Prep-TLC (DCM / MeOH = 15 : 1) to give the title
compound as a light yellow solid.

1H NMR (400 MHz, CDCl3) δ 7.76–7. 42 (m,1H), 7.68 (s, 1H), 7.53 (s, 1H), 7.20–7.12 (m, 2H), 5.86–5.77 (m, 1H), 4.79–4.69 (m, 1H),4.47–4.29 (m, 2H), 4.25–4.08 (m, 2H), 4.06–3.72 (m, 4H), 3.99 (s, 3H), 2.76–2.65 (m, 2H),
2.49–2.28 (m, 2H), 2.25–2.12 (m, 3H).

13C NMR (100 MHz, CDCl3) δ 169.81, 169.36,151.71 (d, J = 238.9 Hz), 145.51, 144.64, 137.83, 136.32, 135.89, 126.35, 121.41, 116.44 (d,J = 26.0 Hz), 111.88, 103.09 (d, J = 24.0 Hz), 71.94, 68.10, 57.65, 43.24, 42.24, 39.02, 37.83,32.49, 22.01.

LCMS M/Z (M+H) 425.

[α]27D +8.8 (c 0.78, CHCl3, 99% ee).

DESIRED S ISOMER

(S)-1-(3-((2-fluoro-4-(1-methyl-1H-pyrazol-4- yl)phenyl)amino)-1-(tetrahydrofuran-3-yl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridin- 5(4H)-yl)ethanone

aReagents and conditions: (a) 4-bromo-2-fluoro-1-isothiocyanato-benzene, KOtBu, THF, rt (b) CH3I, 40 °C, 51%; (c) hydrazine monohydrate, EtOH, 85 °C; 96%; (d) 1-methyl-4-(4,4,5,5- tetramethyl-1,3,2-dioxaborolan-2-yl)pyrazole, dioxane / water, Na2CO3, Pd(dppf)Cl2, 100 °C, 63%; (e) (R)-tetrahydrofuran-3-yl methanesulfonate, Cs2CO3, DMF, 90 oC, 42%.

The crude residue was purified by silica gel chromatography (DCM / MeOH = 100:1) to give (S)-1-(3-((2-fluoro-4-(1- methyl-1H-pyrazol-4-yl)phenyl)amino)-1-(tetrahydrofuran-3-yl)-6,7-dihydro-1Hpyrazolo[4,3-c]pyridin-5(4H)-yl)ethanone as a light yellow solid.

1H NMR (400 MHz, CDCl3) δ 7.76–7.72 (m, 1H), 7.68 (s, 1H), 7.53 (s, 1H), 7.20–7.12 (m, 2H), 5.86–5.77 (m, 1H), 4.79–4.69 (m, 1H), 4.47–4.29 (m, 2H), 4.25–4.08 (m, 2H), 4.06– 3.72 (m, 4H), 3.99 (s, 3H), 2.76–2.65 (m, 2H), 2.49–2.28 (m, 2H), 2.25–2.12 (m, 3H).

13C NMR (100 MHz, CDCl3) δ 169.8, 169.4, 151.7 (d, J = 238.9 Hz), 145.5, 144.64, 137.83, 136.3, 135.9, 126.4, 121.4, 116.4 (d, J = 26.0 Hz), 111.9, 103.1 (d, J = 24.0 Hz), 71.9, 68.1, 57.7, 43.2, 42.2, 39.0, 37.8, 32.5, 22.0.

LCMS m/z (M+H) 425.

[α]27 D -11.0 (c 1.0, CHCl3, 99% ee).

HRMS m/z 425.2093 (M + H+ , C22H25FN6O2, requires 425.2057).

//////////GNE-272, Genentech, CBP, EP300, cancer, immune system regulation

[H][C@@]1(CCOC1)N1N=C(NC2=C(F)C=C(C=C2)C2=CN(C)N=C2)C2=C1CCN(C2)C(C)=O

Clenbuterol

• Clenbuterol hydrochloride, NAB-365, Siropent

Clenbuterol, marketed as Dilaterol, Spiropent, Ventipulmin,^[1] is a sympathomimetic amine used by sufferers of breathing disorders as a decongestant and bronchodilator. People with chronic breathing disorders such as asthma use this as a bronchodilator to make breathing easier. It is most commonly available as the hydrochloride salt, clenbuterol hydrochloride.^[2]

Effects and dosage

Clenbuterol is a β₂ agonist with some structural and pharmacological similarities to epinephrine and salbutamol, but its effects are more potent and longer-lasting as a stimulant and thermogenic drug. It causes an increase in aerobic capacity, central nervous system stimulation, blood pressure, and oxygen transportation. It increases the rate at which body fat is metabolized while increasing the body’s basal metabolic rate (BMR). It is commonly used for smooth muscle-relaxant properties as a bronchodilator and tocolytic.

Clenbuterol is also prescribed for treatment of horses, but equine use is usually the liquid form.

Human use

Clenbuterol is approved for use in some countries, free or via prescription, as a bronchodilator for asthma patients.^[3]

Legal status

Clenbuterol is not an ingredient of any therapeutic drug approved by the US Food and Drug Administration^[3] and is now banned forIOC-tested athletes.^[4] In the US, administration of clenbuterol to any animal that could be used as food for human consumption is banned by the FDA.^[5][6]

Clenbuterol is a therapeutic drug for asthma and COPD, approved for human use in some countries in Europe (Bulgaria and Russia) and Asia (China).

Weight-loss drug

Although often used by bodybuilders during their “cutting” cycles,^{[citation needed]} the drug has been more recently known to the mainstream, particularly through publicized stories of use by celebrities such as Victoria Beckham,^[4] Britney Spears, and Lindsay Lohan, ^[7] for its off-label use as a weight-loss drug similar to usage of other sympathomimetic amines such as ephedrine, despite the lack of sufficient clinical testing either supporting or negating such use.

By bromination of 4-amino-3,5-dichloroacetophenone (I) with Br2 in CHCl3 to give 4-amino-3,5-dichloro-alpha-bromoacetophenone (II), m.p. 140-5 C, which is condensed with tert-butylamine (III) in CHCl3 to 4-amino-3,5-dichloro-alpha-tertbutylaminoacetophenone hydrochloride (IV), m.p. 252-7 C; this product is finally reduced with NaBH4 in methanol.

Synthesen von neuen Amino-Halogen-substituierten Phenyl-aminothanolen. Arzneim-Forsch Drug Res 1972, 22, 5, 861-869

CLIP

Synthesis and Characterization of Bromoclenbuterol

Ravi Kumar Kannasani^*, Srinivasa Reddy Battula, Suresh Babu Sannithi, Sreenu Mula and Venkata Babu VV

R&D Division, RA Chem Pharma Limited, API, Hyderabad, Telangana, India

*Corresponding Author:

Ravi Kumar Kannasani
R&D Division, RA Chem Pharma Limited
API, Prasanth Nagar, Hyderabad, Telangana, India
Tel: +919000443184
E-mail: kannasani.ravi@rachempharma.com

http://www.omicsonline.org/open-access/synthesis-and-characterization-of-bromoclenbuterol-2161-0444-1000397.php?aid=79341

Citation: Kannasani RK, Battula SR, Sannithi SB, Mula S, Babu VVV (2016) Synthesis and Characterization of Bromoclenbuterol. Med Chem (Los Angeles) 6:546-549. doi:10.4172/2161-0444.1000397

Clenbuterol, it is most commonly available as the hydrochloride salt, clenbuterol hydrochloride. Clenbuterol, marketed as Dilaterol, Spiropent, Ventipulmin, and also generically as clenbuterol, is a sympathomimetic amine used for breathing disorders as a decongestant and bronchodilator. People with chronic breathing disorders such as asthma use this as a bronchodilator to make breathing easier. Clenbuterol is a β2 agonist with some structural and pharmacological similarities to epinephrine and salbutamol, but its effects are more potent and longerlasting as a stimulant and thermogenic drug. It causes an increase in aerobic capacity, central nervous system stimulation, blood pressure, and oxygen transportation. It increases the rate at which body fat is metabolized while increasing the body’s BMR. It is commonly used for smooth muscle-relaxant properties as a bronchodilator and tocolytic. Clenbuterol is also prescribed for treatment of horses, but equine use is usually the liquid form

Clenbuterol Hydrochloride was first synthesized at Thomae; a Boehringer Ingelheim research facility in Biberach, Germany, in 1967. The synthesis of Clenbuterol Hydrochloride was patented in the United States in 1970. After comprehensive clinical trials, Clenbuterol Hydrochloride was approved for the treatment of reversible airway obstruction in Germany in 1976 and later as a veterinary pharmaceutical for the treatment of bronchiolytic disorders in Germany in 1980. Boehringer Ingelheim markets Clenbuterol Hydrochloride as Spirospent for Human Pharmaceuticals and as Ventipulmin for Veterinary Pharmaceuticals. Clenbuterol Hydrochloride is not approved by the Federal Drug Administration for human use in the United States.

As per the available literature [4–7], clenbuterol hydrochloride was synthesized from 4-amino acetophenone (Scheme 1). Initially 4-amino acetophenone (1) was reacted with chlorine to afford 4-amino-3,5- dichloro acetopheneone (2) which was further reacted bromine to give 1-(4-amino-3,5-dichlorophenyl)-2-bromoethanone (3). The obtained bromo compound was reacted tertiary butyl amine to afford 2-(tertbutylamino)- 1-(4-amino-3,5-dichlorophenyl)ethanone (4), which was further reduced with sodium borohydride to give clenbuterol base (5) and converted in to hydrochloride salt by using alcoholic HCl to get clenbuterol hydrochloride (6).

In the synthesis of clenbuterol hydrochloride, first step was a double chlorination of 4-aminoacetophenone (1) through an electrophillic aromatic substitution reaction to yield 4-amino-3,5- dichloroacetophenone (2). Due to the ortho/para directing, amino group and the meta directing, electron withdrawing, acetyl group, chlorination of 4-aminoacetophenone occurs primarily at the 3 and 5 positions over the 2 and 6 positions. Therefore, under chlorination would produce only the mono chlorinated impurity, 4-amino-3- chloroacetophenone. Under these conditions, over chlorination does not result in the addition of chlorine to the 2 and 6 positions because the amino and acetyl groups do not direct that addition. Even though chlorides are ortho/para directing and direct to the 2 and 6 position, chlorides are also deactivating. After close observation on this chlorination reaction, it was noted that the formed mono chlorinated impurity (Scheme 2) (4-amino-3-chloro acetophenone) caused the formation of process related impurity (bromoclenbuterol) in clenbuerol synthesis.

References for above

1. International Conference on Harmonization (ICH) Guidelines (2002) Q3A (R) Impurities in New Drug Substances.
2. ICH (2006) Impurities in New Drug Products. Q3B (R1).
3. Srinivasulu R, Ravi Kumar K, Nageswararao K (2016) Synthesis of 3,4-dihydropyrimidin-2(1H)-ones using camphor sulfonic acid as a catalyst under solvent-free conditions. Derpharma chemica 8: 375-379.
4. Antuna AZ, Ivan L, Pablo RG, Julio R, Jose, et al. (2011) V. Tetrahedron 67: 5577-5581.
5. Ehrhardt JD (1990) Synthesis of nonadeutero-clenbuterol. Journal of labeled compounds and radiopharmaceuticals 28: 725-729.
6. Drabb TW (1990) Method for the preparation of 4′-(substituted)-amino-2-(substituted) Amino-3’,5′-dichloroacetophenone and salts thereof Trenton. NJ Patent: US4906781A.
7. Bentley TJ (1984) Method for the preparation of 1-(4′-amino-3′,5′-dichlorophenyl)-2-alkyl(or dialkyl)aminoethanols. US4461914 A.

References