Process for R-epimer enrichment of 16,17-acetal derivatives of 21-acyloxy pregna,4-dien-11.beta., 16.alpha., 17.alpha.-triol-3,20-dione derivatives
AssigneeAltana Pharma AG
InventorBeate Gutterer
Life of this patent
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Abstract
R-epimer enrichment of 16,17-acetal derivatives of 21-acyloxy pregna-1,4-dien-11beta,16alpha,17alpha-triol-3,20-dione derivatives is effected by fractional crystallization.
Claims17
A process for increasing the proportion of R-epimer in an R/S-epimer mixture of compounds of formula I
- wherein R1 is 3-8C-cycloalkyl and R2 is 1-7C-alkylcarbonyl or 3-8C-cycloalkylcarbonyl, which comprises subjecting the R/S-epimer mixture of the compounds of formula I to fractional crystallization carried out from a solution of the R/S-epimer mixture of formula I in a mixture of water and a suitable, water-miscible organic solvent.
A process for the production of an R/S-epimer mixture of [11 beta, 16 alpha (R,S)]-16,17-[(cyclohexylmethylene)bis(oxy)]-11-hydroxy-21-(2-methyl-1-oxopropoxy)-pregna-1,4-diene-3,20-dione and for increasing the proportion of the R-epimer in the mixture, which comprises the steps of (a) subjecting an R/S-epimer mixture of [11 beta, 16 alpha (R,S)]-16,17-[(cyclohexylmethylene)bis(oxy)]-11,21-dihydroxypregna-1,4-diene-3,20-dione to acylation and (b) subjecting the R/S-epimer mixture obtained in step (a) to fractional crystallization in a mixture of water and a suitable, water-miscible organic solvent.
Dependencies are inferred from the claim text.