TREOSULFAN

TREOSULFAN

C₆H₁₄O₈S₂ MW 278.29

FDA APPROVED 1/21/2025 Grafapex

CAS

NSC-39069

• Dihydroxybusulfan
• L-threitol-1,4-dimethanesulfonate

[(2S,3S)-2,3-dihydroxy-4-methylsulfonyloxybutyl] methanesulfonate

Trecondi, Treosulfan was authorized for medical use in the European Union in June 2019

For use in combination with fludarabine as a preparative regimen for allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia and myelodysplastic syndrome

Treosulfan, sold under the brand name Trecondi among others, is an alkylating medication given to people before they have a bone marrow transplant from a donor known as allogeneic hematopoietic stem cell transplantation. It is used as a ‘conditioning’ treatment to clear the bone marrow and make room for the transplanted bone marrow cells, which can then produce healthy blood cells.^[9][10] It is used together with another medicine called fludarabine in adults and children from one month of age with blood cancers as well as in adults with other severe disorders requiring a bone marrow transplant.^[9] It belongs to the family of drugs called alkylating agents.^[9] In the body, treosulfan is converted into other compounds called epoxides which kill cells, especially cells that develop rapidly such as bone marrow cells, by attaching to their DNA while they are dividing.^[9]

The most common side effects include infections, nausea (feeling sick), stomatitis (inflammation of the lining of the mouth), vomiting, diarrhea, and abdominal pain (belly ache).^[9] Tiredness, febrile neutropenia (low white blood cell counts with fever) and high blood levels of bilirubin (a breakdown product of red blood cells) are also seen in more than 1 in 10 adults, and rash also affects more than 1 in 10 children.^[9] The most common adverse reactions include musculoskeletal pain, stomatitis, pyrexia, nausea, edema, infection, and vomiting.^[7] Selected grade 3 or 4 nonhematological laboratory abnormalities include increased GGT, increased bilirubin, increased ALT, increased AST, and increased creatinine.^[7]

Treosulfan was authorized for medical use in the European Union in June 2019,^[9] and approved for medical use in the United States in January 2025.^[7][11]

Medical Uses

Treosulfan in combination with fludarabine is indicated as part of conditioning treatment prior to allogeneic haematopoietic stem cell transplantation in adults with malignant and non malignant diseases, and in children older than one month with malignant diseases.^[7][9]

History

Two main studies showed that treosulfan is at least as effective as busulfan, another medicine used to prepare people for haematopoietic stem cell transplantation.^[9]

In one of the studies, involving 570 adults with acute myeloid leukaemia (a blood cancer) or myelodysplastic syndromes (conditions in which large numbers of abnormal blood cells are produced), 64% of patients given treosulfan (with fludarabine) had a successful transplant and were alive and disease-free after 2 years, compared with 51% of patients given busulfan (with fludarabine).^[9]

In an additional study in 70 children with blood cancers, 99% of children given treosulfan (with fludarabine) were alive three months after their transplant.^[9]

Efficacy was evaluated in MC-FludT.14/L Trial II (NCT00822393), a randomized active-controlled trial comparing treosulfan to busulfan with fludarabine as a preparative regimen for allogeneic transplantation. Eligible patients included adults 18 to 70 years old with AML or MDS, Karnofsky performance status ≥ 60%, and age ≥ 50 years or hematopoietic cell transplantation comorbidity index [HCTCI] score > 2. There were 570 patients randomized to treosulfan (n=280) or busulfan (n=290).

Society and culture

Legal status

Treosulfan was authorized for medical use in the European Union in June 2019,^[9] and approved for medical use in the United States in January 2025.^[11][12][13]

The US Food and Drug Administration granted orphan drug designation to treosulfan in 1994, for the treatment of ovarian cancer;^[14] and in 2015, for conditioning treatment prior to hematopoietic stem cell transplantation in malignant and non-malignant diseases in adults and pediatric patients.^[15]

In February 2004, orphan designation (EU/3/04/186) was granted by the European Commission to medac Gesellschaft fuer klinische Spezialpräparate mbH, Germany, for treosulfan for the conditioning treatment prior to haematopoietic progenitor cell transplantation.^[16]

Names

Treosulfan is the international nonproprietary name.^[17]

Treosulfan is sold under the brand names Trecondi^[9] and Grafapex.^[7]

SYN

Treosulfan is an active ingredient of the drug Ovastat . Treosulfan is indicated for the treatment of ovarian cancer and belongs to the class of alkylating agents, which prevents the growth and division of cancerous cells.

US3155702 discloses the preparation of Treosulfan by methanesulphonation of (2S,3S)- l,4-dibromobutane-2,3-diol with excess amount of silver methanesulphonate. The presence of free 2,3-diol in the starting material leads to side reactions and formation of undesired by-products which necessitates an additional purification step and thereby results in lower yields. Further, an additional filtration operation is also required to remove silver bromide salt generated during the process and un-reacted silver methanesulphonate, which makes the process less attractive for commercial manufacturing.

US3246012 discloses the preparation of Treosulfan by protection of hydroxyl group of dialkyl tartrates with corresponding aldehyde, ketone or a reactive derivatives to form corresponding cyclic 2,3-O-acetals and 2,3-O-ketals of butanetetrol esters followed by reduction using lithium aluminium hydride to obtain 2,3-O-acetal or ketal protected butanetetrol, which is further methanesulphonated and treated with acid. The use of highly pyrophoric and hazardous reducing agent renders the above process not ideal for industrial production. Organic Syntheses, Coll. Vol. 10, p. 297, 2004 discloses a similar reaction sequence followed by the final de-protection of methanesulphonated 2,3-O-diisopropylidene-L- threitol in methanesulfonic acid at reflux temperature, which leads to a sluggish reaction mixture and a higher number of impurities due to maintaining the reaction mixture for longer time at higher temperature.

IN 1568/MUM/2012 also discloses similar reaction sequence involving reduction of dimethyl-2,3-0-isopropylidene-L-tartrate by sodium-bis(2-methoxyethoxy) aluminium hydride followed by methanesulphonation and final deprotection with formic acid to yield Treosulfan.

KR101367641 describes reduction using lithium borohydride, which requires about 14 hours to complete the reaction and is further extended due to involvement of column chromatography purification. Tetrahedron, vol. 49, no. 30, p. 6645, 1993 describes reduction using sodium borohydride and lithium chloride, followed by flash chromatography purification. Reduction conditions as per Chem. Pharm. Bull. Vol. 42, No. 3, p. 68, 1994, are again not commercially feasible because of lithium aluminium hydride as reducing agent.

Haberland, M., Weber, S., Sharma, A. K., Upadhyay, S., Dua, H., Musmade, S., Singh, G., Lahiri, S., & Cabri, W. (2019). A process for the preparation of Treosulfan (Patent No. WO2019043587A2).

WO2019043587A2

EXAMPLES Detailed experimental parameters suitable for the preparation of Treosulfan or intermediates according to the present invention are provided by the following examples, which are intended to be illustrative and not limiting.

Reference Example 1 (repetition of Tetrahedron, vol. 46, No. 12, p. 4165, 1990):

A reaction mixture of dimethyl-L-tartrate (10. Og), p-toluene sulfonic acid (0.013g) and p- anisaldehydedimethylacetal (l l.Og) in toluene (150ml) was refluxed and the azeotropical mixture of toluene-methanol was continuously removed from the reaction mixture for 3-5 hours. The reaction mixture was cooled to ambient temperature, diluted with dichloromethane (50ml) and neutralised by addition of potassium carbonate (5.0g) followed by stirring for an hour . The reaction mixture was filtered and filtrate was evaporated to give yellow crude compound, which was further dissolved in dichloromethane (25ml) followed by addition of petroleum ether (100ml) and stirred for an hour at ambient temperature. The solid was filtered, washed with petroleum ether (20ml) and dried under vacuum at 35-40°C for 15-20 hours to obtain 16.63g (72.15%) of dimethyl (4R,5R)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5-dicarboxylate having purity 98.4% by HPLC.

Reference Example 2 (repetition of Synthesis, No. 15, p. 2488-90, 2008):

A reaction mixture of dimethyl-L-tartrate (5.0g), p-toluene sulfonic acid (0.0064g) and p- anisaldehyde dimethylacetal (5.35g) in toluene (25ml) was refluxed and the azeotropical mixture of toluene-methanol was continuously removed from the reaction mixture for 3-5 hours. The reaction mixture was cooled to ambient temperature, diluted with dichloromethane (25ml) and neutralised by addition of potassium carbonate (5.0g) followed by stirring for an hour. The reaction mixture was filtered and filtrate was evaporated to give yellow crude residues. The crude was further re-crystallized in petroleum ether (25ml), filtered the solid and washed with petroleum ether (15ml) followed by drying under vacuum at 35-40°C for 15-20 hours to obtain 7.4g (89.15%) of dimethyl (4R,5R)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5-dicarboxylate having purity 98.8% by HPLC. Example-1: Preparation of dimethyl (4R,5R)-2-(4-methoxyphenyl)-l,3-dioxolane- 4,5-dicarboxylate

A reaction mixture of dimethyl-L-tartrate (500g), p-toluene sulfonic acid (5.38g) and p- anisaldehyde dimethylacetal (665g) in toluene (2250ml) was refluxed to 110-115°C. The azeotropical mixture of toluene-methanol was continuously removed from the reaction mixture till the completion of the reaction. The reaction mixture was cooled to ambient temperature and quenched with aq. saturated sodium bicarbonate solution (2500ml), layers were separated. Resulting organic layer was washed with water (2500ml x 2) followed by evaporation of organic layer. Isopropyl alcohol (3500ml) was charged to the residue and heated to 60-70°C followed by cooling at ambient temperature. Reaction mixture was stirred at 0-5°C for 1-2 hours and filtered. The solid thus obtained was washed with pre- cooled isopropyl alcohol and dried under vacuum at 35-40°C for 15-20 hours to obtain 767.0g (92.93%) of dimethyl (4R,5R)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5- dicarboxylate having purity 99.97% by HPLC.

Example-2: Preparation of (4S,5S)-2-(4-methoxyphenyl)-l ₅3-dioxo!ane-4,5- diyifdimethanol

Method-l :To a mixture of dimethyl (4R,5R)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5- dicarboxylate (765g), Iodine (13. lg) in tetrahydrofuran (3750ml) and water (76ml), sodium borohydride (146.52g) was added at 0-15°C and stirred for 1 -2 hours at ambient temperature. The reaction was quenched with 30% aq. ammonium chloride (6100ml) solution and dichloromethane (7650ml). The layers were separated and the aqueous layer was extracted by dichloromethane (3800ml x 3) followed by washing of combined organic layers with water (3800ml), The resulting organic layer was evaporated at 35-65°C to obtain 525.0g (83.9%) of (4S,5S)-2-(4-methoxyphenyl)-l,3- dioxolane-4,5-diyl]dimethanol having purity 99.72% by HPLC. Method-2: To a mixture of dimethyl (4R,5R)-2-(4-methoxyphenyl)-l,3-dioxolane- 4,5-dicarboxylate (765g), Iodine (13.10g) in tetrahydrofuran (3750ml) and water (76.5ml), sodium borohydride (146.52g) was added at 0-10°C and stirred for Ihours at 0-5°C and stirred for 3-4 hours at ambient temperature. The reaction was quenched with 30% aq. ammonium chloride (6120ml) solution and dichloromethane (7650ml) at ambient temperature. The layers were separated and the aqueous layer was extracted by dichloromethane (3825m! x 3) followed by washing of combined organic layers with water (3825ml). The resulting organic layer was evaporated at 50-60°C to obtain 525 g (84.7%) of (4S,5S)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5-diyl]dirnethaiiol having purity 99.72% by HPLC. Example-3: Preparation of (4S,5S)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5- diyl]bis(methylene) dimethanesulfonate

Method-l:To a solution of (4S,5S)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5- diyl]dimethanol (145g) in dichloromethane (2175ml), pyridine (191g) and methanesulphonyl chloride (190. l g) was added at 0-5 ^°C. The reaction mixture was stirred for 2-3 hours at ambient temperature followed by quenching with water (1450ml). The organic layer was washed with water (1450ml x 4) and evaporated. The resulting residue was added to isopropanol (725ml) and stirred for 1-2 hours at ambient temperature and further for 1-2 hours at 0-5 C. The solid was filtered and washed with pre-cooled isopropanol (145ml). The resulting product was dissolved in acetone (1300ml) followed by addition of isopropanol (2610ml). Resulting reaction mixture was stirred for 1-2 hours at ambient temperature and then cooled at 0-5 ^°C. The solid thus obtained was filtered and washed with pre-cooled isopropanol (145ml x 2) and dried under vacuum at 30-35°C for 15-20 hours to give 190.8g (79.4%)of (4S,5S)-2-(4- methoxyphenyl)-l,3-dioxolane-4,5-diyl]bis(methylene) dimethanesulfonate. Method-2: To a solution of (4S,5S)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5- diyl]dimethanol (525, Og) in dichloromethane (7350ml), di-isopropylamine (663. Og) was added at ambient temperature followed by addition of methanesulphonyl chloride solution (624. Og in 525ml dichloromethane) at 0-10°C. The reaction mixture was stirred for 1-2 hours at 0-10 ^°C followed by stirring for 3-4 hours at ambient temperature. The organic layer was washed with water (2 x 5250ml) and evaporated. The residues were dissolved in acetone (4725ml) followed by addition of isopropanol (9450ml), stirred for about 1-2 hour at ambient temperature and then at 0-5 ^°C for 1-2 hours. The resulting solid was filtered, washed with pre-cooled isopropanol (525 x 2 ml)and dried under vacuum at 35-45°C for 15-20 hours to give 705.0g (81.45%) of (4S,5S)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5-diyl]bis(methylene)

dimethanesulfonate having purity 99.92% by HPLC.

Example-4: Preparation of Treosulfan

Method-1: To a solution of (4S,5S)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5- diyl]bis(methylene) dimethanesulfonate (745. Og) in methanol (7450ml), concentrated hydrochloric acid (260ml) was added at 15-25°C followed by stirring for 10-15 hours at ambient temperature. The reaction mixture was cooled to 0-5°C and further stirred for 1-2 hours at 0-5°C followed by filtration and washing the solid with pre-cooled methanol (745ml). The solid thus obtained was dissolved in acetone (3725ml) followed by microne filtration. Di-isopropyl ether (7450ml) was added to the filtrate and stirred for 1-2 hours at ambient temperature and then cooled at 0-5°C. The solid thus obtained was filtered and washed with di-isopropyl ether (745ml x 2) followed by drying at 30-35°C for 15-20 hours to obtain 96.5g of Treosulfan having purity 99.9% by HPLC.

XRPD of Treosulfan obtained by above process is shown in Fig. 1. Method-2:To a solution of (4S,5S)-2-(4-methoxyphenyl)-l,3-dioxolane-4,5- diyl]bis(methylene)dimethanesulfonate (650. Og) in methanol (6500ml), 9N hydrochloric acid (227.5ml) was added at 0-10°C followed by stirring for 6-8 hours at ambient temperature. The reaction mixture was cooled to 0-5°C and further stirred for 1-2 hours followed by filtration and washing the solid with pre-cooled methanol (2 x 650ml). The solid thus obtained was dissolved in acetone (3250ml). Di-isopropyl ether (6500ml) was added to the resulting solution, stirred for 1-2 hours at ambient temperature and then cooled at 0-5°C. The solid thus obtained was filtered and washed with di- isopropyl ether (650ml x 2) followed by drying at 30-35°C for 15-20 hours to obtain 312g (68.4) of Treosulfan having purity 99.81% by HPLC.

PATENT

https://patents.google.com/patent/WO2020064815A1/en

Example 1 – Preparation of form B using water/isopropanol

99.8 mg treosulfan were weighed in a vial (volume 4.0 ml) which was equipped with a PTFE (Polytetrafluoroethylene) sealing and a stirrer. 1.5 ml of a mixture of 80 % by weight water and 20 % by weight isopropanol preheated to 65°C were then added. The resulting solution was completely taken up with a syringe (volume 5 ml) and filtered using a 0.2 pm filter into a second vial (volume 4.0 ml) . The syringe, second vial and filter had been tempered at 65°C before use. The solvents were allowed to evaporate from the open vial at room temperature to dryness which resulted in formation of crystals.

The XRPD pattern of the obtained crystals of form B according to the invention is shown in Figure 1. 

PATENT

1568/MUM/2012

Abstract

Abstract: The present invention provides a convenient and cost-effective process for preparation of Treosulfan. The process comprises reduction of dimethyl 2,3-O-isopropylidene-L-tartrate with sodium-bis(2-methoxyethoxy)aluminum hydride to give the alcohol 2,3-O-isopropylidene-L-threitol (III), which on reaction with methanesulfonyl chloride led to 2,3-O-isopropylidene-L-threitol 1,4-bismethanesulfonate of formula (IV) and further treatment of compound (IV) with formic acid gave Treosulfan (I) having desired purity.

Treosulfan (I), chemically known as (2S,3S)-2,3-Dihydroxy-4-memylsidfonyIoxybutylj methanesulfonate is a drug commonly used for treating ovarian cancer. It belongs to the family of anti-cancer medicines called the alkylating agents, which prevent the growth and division of cancerous cells. Treosulfan has been used for bone-marrow ablation before stem-cell transplantation and in the treatment of malignant melanoma and breast cancer.

US 3,155,702 discloses synthesis of Treosulfan by replacement of the halogen function in L-Threitol-l,4-dibromobutane-2,3-diol, by treating with a large excess of an expensive reagent like silver methanesulfonate. Further, the presence of unprotected hydroxyl groups in the starting material inevitably leads to the formation of undesired impurities, which requires additional purification steps for removal of impurities as well for lowering the level of free silver in the active ingredient as per ICH guidelines, which results in lower yields and increases the costs substantially.
Another method reported in US 3,246,012 involves acetal formation of diethyl-L-tartrate with acetone to obtain 2,3-O-isopropylidene-diethyl-L-tartrate, which, when reduced with lithium aluminium hydride gives 2,3-0-methylene-L-threitol. The obtained alcohol was treated with methanesulfonyl chloride to yield the penultimate Treosulfan intermediate, 2,3-O-methylene-L-threitol-1,4-di-(methanesulfonate).

A similar approach which employs tartrate esters in the synthesis of Treosulfan, is disclosed in Organic Syntheses, (1993), Vol.8, p. 155 and Organic .Syntheses, (2004), Coll.Vol.10, p.297. L-tartaric acid is reacted with 2,2-dimethoxypropane in presence of methanol. The resulting methyl ester, dimethyl 2,3-O-isopropylidene-L-tartrate is reduced with lithium aluminium hydride to obtain 2,3-di-O-isopropylidene-L-threitol, which, upon reaction with methanesulfonyl chloride, followed by treatment with methanesulfonic acid yields Treosulfan.
Although these routes involve protection of the diol group and avoid impurities arising out of substitution at those alcohol functionalities, use of a highly pyrophoric, hazardous reagent such as lithium aluminium hydride severely limits their synthetic applicability, especially on commercial scale. Further, the final step involves reaction of 2,3-di-O-isopropylidene-L-threitol with methanesulfonic acid, which is quite sluggish and causes considerable rise in the total number of impurities due to long reaction time.
Thus, there is a need for a convenient, economical process for a commercial scale synthesis of Treosulfan (I), which overcomes the shortcomings of the prior art, does not involve use of hazardous, pyrophoric reagents and yields Treosulfan conforming to regulatory specifications.
The present inventors have developed a novel process for preparation of (2S,3S)-2,3-Dihydroxy-4-methylsulfonyloxybutyl] methanesulfonate (I). The scheme for synthesis comprises reaction of dimethyl 2,3-O-isopropylidene-L-tartrate of formula (II) with sodium-bis(2-methoxyethoxy) aluminum hydride to give the protected diol, 2,3-0-isopropylidene-L-threitoI (III), which on further treatment with methanesulfonyl chloride, followed by reaction of the resultant ester, 2,3-O-isopropyliden-L-threitol 1,4 bismethanesulfonate (IV) with formic acid, yields Treosulfan (I) having desired purity and with impurity levels conforming to ICH guidelines.

Scheme 1; Method embodied in the present invention for the preparation of Treosulfan (I)
In an embodiment, dimethyl 2,3 -O-isopropylidene-L-tartrate of formula (II) was treated with sodium-bis-(2-methoxyethoxy) aluminium hydride in presence of an organic solvent, and in the temperature range of 25 to 80°C, but preferably 60 to 75°C.
The organic solvent was selected from the group of toluene, xylenes, nitrobenzene, hexane, cyclohexane, heptane, N-methyl-2-pyrroIidone, ethers etc.
Upon completion of the reaction, as monitored by TLC, water was carefully added to the reaction mass and the mixture was extracted with a water immiscible organic solvent.
The organic solvent was selected from the group comprising of n-hexane, cyclohexane, heptane, methyl isobutyl ketone, 2-methyl tetrahydrofuran, cyclopentyl methyl ether etc.
The organic layer was separated and concentrated under reduced pressure to give 2,3-0-isopropylidene-L-threitol of formula (III) of desired purity.
It is pertinent to mention that the reaction was quite facile and the desired product was obtained with minimal formation of associated impurities and did not require any subsequent purification.

Further reaction of compound (III) with methanesulfonyl chloride was carried out at 25 to 35°C, in an organic solvent, in presence of an organic base.
The organic solvent was selected from the group comprising of chloroform, ethylene dichloride, dichloromethane, carbon tetrachloride etc., but preferably dichloromethane.
The organic base was selected from triethyl amine, tributyl amine and pyridine.
The reaction mixture was stirred at 25-35°C and after completion of the reaction as monitored by TLC, aqueous solution of sodium bicarbonate was added slowly to the reaction mass. The organic layer was separated, concentrated under reduced pressure and stirred with isopropyl alcohol to obtain the desired compound, 2,3-O-isopropylidene-L-threitol-l,4-bis(methanesulfonate) of formula (IV).
In a further embodiment, compound (TV) was hydrolyzed by treating with formic acid at 25 to 35°C based on TLC. After completion of the reaction, the reaction mass was concentrated and the product Treosulfan (I) was isolated by addition of isopropyl alcohol to the concentrated mass.
It is pertinent to mention that Organic Syntheses (2004), Coll.Vol. 10, p.297 discloses the hydrolysis reaction using methanesulfonic acid in ethanol at reflux temperature. However, the time taken for completion is about ten hours and the procedure is applicable only for laboratory scale reaction. The hydrolysis step disclosed in the present invention is easily scalable and so facile that it takes place at room temperature and within one to two hours. This reduces the time cycle for each batch run and also reduces the possibility of formation of undesired side products.
Dimethyl 2,3-O-isopropylidene-L-tartrate of formula (II) was prepared by the reaction of dimethyl -L-tartrate with acetone by following known synthetic procedures.

The following examples are meant to be illustrative of the present invention. These examples exemplify the invention and are not to be construed as limiting the scope of the invention.
EXAMPLES
Example 1: Synthesis of 2,3-O-isopropylidene-L-threitol (HI)
A solution of dimethyl-2,3-0-isopropylidene-L-tartrate (50.3 g) in toluene (50 ml) was gradually added to the stirred mixture of sodium-bis(2-methoxyethoxy) aluminum hydride (122.8 g) in toluene (50 ml) at 20-40°C. The reaction mixture was heated to 60-80°C, and the reaction was continued till completion, as monitored by TLC. When the reaction was complete, the mass was cooled to 25-3 5°C, quenched with careful addition of water (10ml) and concentrated. Treatment of the resulting residue with methyl tertiary butyl ether, followed by evaporation of the organic layer under reduced pressure afforded 2,3-0-isopropyliden -L-threitol ( III) as pale yellow oil. Yield: 29.8 g (81.2%) [α]D20 + 4.6.°(CHC13, c 5)
Example 2: Synthesis of 2,3-0-isopropylidene-L-threitol-l,4-bis(methanesulfonate)
(IV)
A stirred solution of 2,3-O-isopropylidene-L-threitol (100.2 g), methylene chloride (1250
ml) and pyridine (146.3 g) was cooled to 0-5°C and methanesulfonyl chloride (176.6 g)
was slowly added to it. Temperature of the reaction mixture was raised to 25-35°C and the
reaction was continued at the same temperature till completion of the reaction, as
monitored by HPLC. After completion of the reaction, aqueous sodium bicarbonate
solution was slowly added to the reaction mass and the organic layer was separated.
Aqueous layer from the reaction mixture was extracted with methylene chloride and the
organic layers were combined. Distillation of the organic solvent, optionally followed by
addition of isopropyl alcohol gave the product, 2,3-0-isopropylidene-L-threitol-l,4-
bis(methanesulfonate).
Yield: 160.7 g (79.7%)
[α]D20-21.6°(acetone,c2)

Example 3: Synthesis of Treosulfan (I)
A mixture of formic acid (98%, 1000 ml) and 2,3-0-isopropylidene-L-threitol-l,4-bis(methanesulfonate) (100.5 g) was stirred at room temperature until completion of the desired reaction, as monitored by TLC, When the reaction was complete, the reaction mass was concentrated under reduced pressure..
Treatment of the residue after evaporation with isopropanol yielded the final product Treosulfan, which was optionally subjected to further treatment with acetone and nexanes or petroleum ether, Yield: 74.3 g (85.0%) [α]D20 – 5.3°(acetone, c 2) Purity: > 99 %.

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15. ^ “Treosulfan Orphan Drug Designations and Approvals”. U.S. Food and Drug Administration (FDA). 8 April 2015. Retrieved 9 March 2025.
16. ^ “EU/3/04/186”. European Medicines Agency (EMA). 17 September 2018. Archived from the original on 16 October 2019. Retrieved 21 April 2020.  This article incorporates text from this source, which is in the public domain.
17. ^ World Health Organization (1972). “International nonproprietary names for pharmaceutical substances (INN). recommended INN: list 12”. WHO Chronicle. 26 (10).

External links

• “Treosulfan”. National Cancer Institute.
• ^[1]
• Clinical trial number NCT00822393 for “Clinical Phase III Trial Treosulfan-based Conditioning Versus Reduced-intensity Conditioning (RIC)” at ClinicalTrials.gov

1. Romanski M, Baumgart J, Bohm S, Glowka FK: Penetration of Treosulfan and its Active Monoepoxide Transformation Product into Central Nervous System of Juvenile and Young Adult Rats. Drug Metab Dispos. 2015 Dec;43(12):1946-54. doi: 10.1124/dmd.115.066050. Epub 2015 Oct 1. [Article]
2. EMA Summary of Product Characteristics: Trecondi (treosulfan) powder for solution for infusion [Link]
3. FDA Approved Drug Products: GRAFAPEX (treosulfan) for injection, for intravenous use [Link]
4. EMC Summary of Product Characteristics: Treosulfan 5g Powder for Solution for Infusion [Link]
5. NIH LiverTox: Alkylating Agents [Link]
6. FDA News Release: FDA approves treosulfan with fludarabine as a preparative regimen for alloHSCT in adult and pediatric patients with AML or MDS [Link]

////////TREOSULFAN, Treosulphan, Ovastat, Treosulfano, Grafapex, acute myeloid leukemia, myelodysplastic syndrome, NSC-39069, Dihydroxybusulfan, L-threitol-1,4-dimethanesulfonate, Trecondi, FSA 2025, APPROVALS 2025, EMA 2019, EU 2019

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