Process for the preparation of 16beta-methyl steroid and novel intermediates and intermediates used in the process

摘要

Prodn. of 16 beta -methyl-17 alpha -hydroxy- 4,9(11)-pregnadiene-3,20-dione of formula (I) comprises: (a) treating a 17 alpha -hydroxy-17 beta -nitrile with a dehydrating agent to give a 16,17-dehydro-17-nitrile; (b) protecting the oxo gp. if necessary; (c) reacting with an organometallic methylating agent and hydrolysing the resulting imine to give a methyl ketone; (d) treating with an epoxidising agent in a basic medium to give a 16 alpha ,17 alpha -epoxide; (e) protecting the 20-oxo gp.; (f) reacting with an organometallic methylating agent to give a 16 beta -methyl deriv.; and (g) deprotecting the oxo gps. to give (I).