METHOD OF SELECTIVELY CHANGING 200METHYLPREGNA 3*5*20*21**TRIENEE3*211DIOLLDIACETATE TO 33OXOO200METHYLPREGNAA4*20*21**DIENEE211YLL ACETATE

摘要

The present invention relates to the selective conversion of 20-methylpregna-3,5,20(21)-triene-3,21-diol-diacetate to 3-oxo-20-methylpregna-4,20(21)- diene-21-yl-acetate by the use of a halogenated solvent and a halogenated acid. This process provides improved recovery of 3-oxo-20-methylpregna-4,20(21)- diene-21-yl acetate which is a useful intermediate in the preparation of progesterone.