process for the prapratzione 17 monoesters of 17 to 21 diossisteroidi for hydrolysis of corpispondenti 17 21 ortoesteri cyclic ph control side

摘要

This invention relates to an improved process for the preparation of 17-monoesters of 17 alpha , 21-dihydroxy-20-keto-steroids which consists in carrying out the hydrolysis of corresponding 17,21-cyclic orthoesters in a buffered aqueous-organic medium at a pH from about 4 to about 6. This invention also relates to new 17-esters of 17 alpha , 21-dihydroxy-steroids having an epoxy group at the 9 beta , 11 beta -position, useful as intermediates for the preparation of therapeutically active 17-esters.