Process for the production of prednisone 17.21-diacylates

摘要

A novel process for the preparation of prednisone derivatives of the formula <IMAGE> I wherein R1 is alkyl of 1 to 4 carbon atoms and R2 is selected from the group consisting of hydrogen and hydrocarbon of 1 to 8 carbon atoms comprising reacting a compound of the formula <IMAGE> II with a reducing agent to obtain a compound of the formula <IMAGE> III reacting the latter with a strong base in the presence of copper ions and oxygen to obtain a compound of the formula <IMAGE> IV reacting the latter with hydroxylamine to obtain a compound of the formula <IMAGE> V in its syn or anti isomeric form or a mixture thereof, reacting the latter with an acylating agent derived from a radical of the formula <IMAGE> and with a reducing agent to obtain a compound of the formula <IMAGE> VI in its Z or E isomeric form or a mixture thereof, subjecting the latter to treatment with an epoxidizing agent and then a dehydrating agent to obtain a compound of the formula <IMAGE> VII reacting the latter with a halogenation agent and subjecting the resulting product to hydrolysis to obtain a compound of the formula <IMAGE> VIII wherein Hal is a halogen and reacting the latter with a derivative of an acyl of the formula R1CO- to obtain the compound of formula I which are known compounds.