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