Selective enzymatic esterification and solvolysis of epimeric vitamin D analog and separation of the epimers

• US 20030166226A1
• Filed: 01/09/2003
• Published: 09/04/2003
• Est. Priority Date: 01/10/2002
• Status: Active Grant

• Current Assignee: Teva Pharmaceuticals USA, Inc. (Teva Pharmaceutical Industries Limited)
• Original Assignee: Teva Pharmaceuticals USA, Inc. (Teva Pharmaceutical Industries Limited)
• Inventors: Shapiro, Evgeny, Effenberger, Reinhard, Fishman, Ayelet, Schwartz, Anchel, Maymon, Asher
• Granted Patent: US 8,129,173 B2
• Time in Patent Office: Days
• US Class Current: 435/198
• CPC Class Codes: C12P 41/004 by esterification of alcohol- or thiol groups in the enantiomers or the inverse reaction
• CPC Class Codes: C12P 7/18 polyhydric

Abstract

Provided is a method of selectively enzymatically esterifying or selectively enzymatically solvolyzing epimers of analogs of vitamin D having a stereogenic center at C-24 that has a free or esterified OH group. The metod can be used, for example, for separating mixed epimers of the vitamin D analog.

Claims

1. A method of selectively enzymatically esterifying the C-24 hydroxyl group of one epimer in a mixture of epimers of a vitamin D analog having a hydroxyl group at the stereogenic C-24 position thereof, comprising the steps of:

a) providing a solution of mixed C-24 epimers of a vitamin D analog having a hydroxyl group at the C-24 position thereof and an esterifying agent in an organic solvent, and

b) contacting the solution with a lipase.

2. The method of claim 1 wherein the mixed C-24 epimers are mixtures of C-24 epimers of compounds selected from compounds of general formula III or IX

3. The method of claim 2 wherein R₁ and R₂ are both H.

4. The method of claim 2 wherein the lipase is Alcaligenes sp lipase.

5. The method of claim 2 wherein the lipase is Pseudomonas sp. lipase.

6. The method of claim 2 wherein the lipase is fixed.

7. The method of claim 2 wherein the lipase is free.

8. The method of claim 2 wherein the mixed C-24 epimers are an epimeric mixture at C-24 of [1α

, 3β

,5E,7E,20R]-1,3-bis(tert-butyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R,S)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

9. The method of claim 8 wherein the C-24 OH epimer selectively esterified is [1α

, 3β

,5E,7E,20R]-1,3-bis(tertbutyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

10. The method of claim 2 wherein the mixed epimers are an epimeric mixture at C-24 of [1α

, 3β

,5Z,7E,20R]-1,3-bis(tert-butyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R,S)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

11. The method of claim 10 wherein the C-24 OH epimer selectively esterified is [1α

, 3β

,5Z,7E,20R]-1,3-bis(tertbutyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

12. The method of claim 2 wherein the esterifying agent is selected from the group consisting of the acyl halides, the acid anhydrides, and the vinyl esters of lower alkyl carboxylic acids having 2 to 6 carbon atoms.

13. The method of claim 12 wherein the esterifying agent is selected from the group consisting of acetyl chloride, acetic anhydride, vinyl acetate, and vinyl butyrate.

14. The method of claim 2 wherein the organic solvent is a linear or branched alkane having up to 12 carbon atoms, a dialky ether, or an alkyl ester of an alkyl carboxylic acid.

15. The method of claim 14 wherein the solvent is hexane, ethyl acetate, or diisopropyl ether.

16. A method of selectively enzymatically esterifying the C-24 hydroxyl group of one epimer in a mixture of epimers of a vitamin D analog having a hydroxyl group at the stereogenic C-24 position thereof, comprising the steps of:

a) providing a solution of mixed C-24 epimers of a vitamin D analog having a hydroxyl group at the C-24 position thereof and an esterifying agent selected from acetyl chloride, acetic anhydride, vinyl acetate and vinyl butyrate in an organic solvent selected from hexane, ethyl acetate, and diisopropyl ether, and

b) contacting the solution with a lipase selected from Alcaligenes sp. lipase and Psudomonas sp lipase,

wherein the mixed C-24 epimers are mixtures of C-24 epimers of compounds selected from compounds of general formula III or IX

where R₁ and R₂ are hydrogen or tert-butyldimethylsilyl and R₃ is a cyclopropyl or isopropyl group.

17. A method of enzymatically esterifying the C-24 hydroxyl group of a vitamin D analog having a hydroxyl group at the C-24 position thereof and selected from compounds of general formula III or IX

18. The method of claim 17 wherein the esterifying agent is selected from acetyl chloride, acetic anhydride, vinyl acetate, and vinyl butyrate.

19. The method of claim 18 wherein the solvent is hexane, ethyl acetate, or diisopropyl ether.

20. A method of selectively enzymatically solvolyzing the esterified C-24 hydroxyl group of one epimer in a mixture of esterified C-24 epimers of a vitamin D analog having an esterified hydroxyl group at the C-24 stereogenic position thereof comprising the steps of:

a) providing a solution of the mixed esterified C-24 epimers of a vitamin D analog having a hydroxyl group at C-24 and a solvolysis agent in an organic solvent, and

b) contacting the solution with a lipase.

21. The method of claim 20 wherein the mixed esterified C-24 epimers are esters of mixed epimers of compounds of general formula III or IX,

22. The method of claim 21 wherein R₁ and R₂ are both H.

23. The method of claim 21 wherein the lipase is Alcaligenes sp lipase.

24. The method of claim 21 wherein the lipase is Pseudomonas sp. lipase.

25. The method of claim 21 wherein the lipase is fixed.

26. The method of claim 21 wherein the lipase is free.

27. The method of claim 21 wherein the esterified mixed C-24 epimers are an epimeric mixture at C-24 of C-24 esters of [1α

, 3β

,5E,7E,20R]-1,3-bis(tert-butyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R,S)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

28. The method of claim 27 wherein the esterified C-24 OH epimer selectively solvolyzed is the ester of [1α

, 3β

,5E,7E,20R]-1,3-bis(tertbutyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

29. The method of claim 21 wherein the esterified mixed epimers are an epimeric mixture at C-24 of C-24 esters of [1α

, 3β

,5Z,7E,20R]-1,3-bis(tert-butyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R,S)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

30. The method of claim 29 wherein the esterified C-24 OH epimer selectively solvolyzed is [1α

, 3β

,5Z,7E,20R]-1,3-bis(tertbutyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

31. The method of claim 21 wherein the solvolysis agent is water.

32. The method of claim 21 wherein the solvolysis agent is an alcohol.

33. The method of claim 21 wherein the solvent is a linear or branched alkane having up to 12 carbons, an alkyl ester of an alkyl carboxylic acid, or a dialkyl ether.

34. The method of claim 32 wherein the solvent is hexane, ethyl acetate, or diisopropyl ether.

35. A method of selectively enzymatically solvolyzing the esterified C-24 hydroxyl group of one epimer in a mixture of esterified C-24 epimers of a vitamin D analog having an esterified hydroxyl group at the C-24 stereogenic position thereof comprising the steps of:

a) providing a solution of the mixed esterified C-24 epimers of a vitamin D analog having a hydroxyl group at C-24 and a solvolysis agent that is water or an alkyl alcohol in an organic solvent selected from hexane, diisopropyl ether, and ethyl acetate; and

b) contacting the solution with a lipase selected from Alcaligenes sp. lipase and Pseudomonas sp. lipase;

wherein

the mixed esterified C-24 epimers are esters of mixed epimers of compounds of formula general formula III or IX,

where R₁ and R₂ may be the same or different and represent hydrogen or tert-butylsilyl, and R₃ is cyclopropyl or iso-propyl.

36. A method of enzymatically solvolyzing the esterified C-24 hydroxyl group of an epimer of a vitamin D analog having an esterified hydroxyl group at the C-24 stereogenic position thereof comprising the steps of:

a) providing a solution of the esterified C-24 epimer of a vitamin D analog having a hydroxyl group at C-24 and a solvolysis agent; and

b) contacting the solution with a lipase selected from Alcaligenes sp. lipase and Pseudomonas sp. lipase;

wherein

the esterified C-24 epimer is a C-24 ester of a compound of formula general formula III or IX,

where R₁ and R₂ may be the same or different and represent hydrogen or a hydroxy protecting group and R₃ is a lower alkyl, cycloalkyl, or aryl group.

37. The method of claim 36 wherein the solvolysis agent is water or a lower alkyl alcohol.

38. The method of claim 36 wherein the solvent is hexane, diisopropyl ether, or ethyl acetate.

39. In a method for making a diasteriomerically pure vitamin D analog, the step of selectively enzymatically esterifying at the 24 position a vitamin D analog having a hydroxyl group at the 24 position.

40. In a method for making a diasteromerically pure vitamin D analog, the step of selectively enzymatically solvolyzing the C-24 ester of one epimer in a mixture of epimers of a vitamin D analog having esterified hydroxyl groups at the C-24 stereogenic center thereof.

41. In a process for making calcipotriene, (5Z, 7E, 22E, 24S)-24-cyclopropyl-9,10-secochola-5,7,10(19), 22-tetraene-1α

-3β

-24-triol, chromatographically separating mixed epimers of a vitamin D analog having an OH group at a C-24 stereogenic center by a method including a step selected from selective enzymatic esterification and selective enzymatic solvolysis wherein

when selective enzymatic solvolysis is chosen, the OH group at C-24 of both epimers is first esterified, and

when selective esterification is chosen, vinyl acetate is the esterification agent, and wherein

the selective esterification or selective solvolysis is effected with Alcaligenes sp. lipase or Pseudomonas sp. lipase.

42. A method of separating mixed epimers of a vitamin D analog having a hydroxyl group in the 24 position, wherein C-24 is the epimeric center, comprising the steps of:

a) selectively enzymatically esterifying the hydroxyl group at C-24 of one epimer, and

b) chromatographically separating esterified epimer from nonesterified epimer.

43. The method of claim 42 wherein the mixed C-24 epimers are mixtures of C-24 epimers of compounds selected from compounds of general formula III or IX

44. The method of claim 43 wherein the mixed C-24 epimers are an epimeric mixture at C-24 of [1α

, 3β

,5E,7E,20R]-1,3-bis(tert-butyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R,S)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

45. The method of claim 44 wherein the C-24 OH epimer selectively esterified is [1α

, 3β

,5E,7E,20R]-1,3-bis(tertbutyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

46. The method of claim 43 wherein the mixed epimers are an epimeric mixture at C-24 of [1α

, 3β

,5Z,7E,20R]-1,3-bis(tert-butyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R,S)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

47. The method of claim 46 wherein the C-24 OH epimer selectively esterified is [1α

, 3β

,5Z,7E,20R]-1,3-bis(tertbutyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

48. A method of separating mixed C-24 epimers of a vitamin D analog having a hydroxyl group in the C-24 position, wherein C-24 is the epimeric center, comprising the steps of:

a) esterifying the C-24 hydroxyl group of both epimers,

b) selectively enzymatically solvolyzing the C-24 ester so formed of one of the epimers, and

c) chromatographically separating selectively solvolyzed epimer from nonsolvolyzed epimer.

49. The method of claim 48 wherein the mixed C-24 epimers are mixtures of C-24 epimers of compounds selected from compounds of general formula III or IX

50. The method of claim 49 wherein the mixed C-24 epimers are an epimeric mixture at C-24 of [1α

, 3β

,5E,7E,20R]-1,3-bis(tert-butyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R,S)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19),-triene.

51. The method of claim 50 wherein the esterified C-24 OH epimer selectively solvolyzed is an ester of [1α

, 3β

,5E,7E,20R]-1,3-bis(tertbutyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

52. The method of claim 49 wherein the mixed epimers are an epimeric mixture at C-24 of [1α

, 3β

,5Z,7E,20R]-1,3-bis(tert-butyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R,S)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.

53. The method of claim 52 wherein the esterified C-24 OH epimer selectively solvolyzed is an ester of [1α

, 3β

,5Z,7E,20R]-1,3-bis(tertbutyldimethylsiloxy)-20-(3′

-cyclopropyl-3′

(R)-hydroxy-1′

-propenyl)-9,10-secopregna-5,7,10(19)-triene.