GB920521A - 16-methyl steroids - Google Patents

Abstract

The invention comprises (1) a process for the preparation of steroids of the formula <FORM:0920521/IV(a)/1> (wherein R is -CH(a CH3)-CH2-, -(CH2)2-, -CH=CH- or -C(CH3)=CH- and R1 is an acyl group of at most 6 carbon atoms) which comprises selectively hydrogenating the 16-methylene group of a steroid of the formula <FORM:0920521/IV(a)/2> (wherein R is hydrogen or methyl and R11 is an acyl group of at most 6 carbon atoms) to yield the corresponding 16a -methyl-steroid, acylating this to give the 17-acylate, selectively hydrolysing the 3b -acyloxy group and oxidising to convert the 3b -hydroxy-D 5-compound to the desired D 4-3-ketone or D 4,6-3-ketone; and (2) the new steroids 17a -acetoxy-16a -methylpregn-4-ene-3,20-dione, 17a -acetoxy-16a -methylpregna-4,6-diene-3,20-dione, 3b -acetoxy-17a - hydroxy-6,16a -dimethylpregn-5-en-20-one, 3b -acetoxy - 17a - hydroxy-16a -methylpregn-5-en -20 - one, 3b ,17a - diacetoxy-6,16a -dimethyl-pregn-5-en-20-one and 3b ,17a -diacetoxy-16a -methylpregn-5-en-20-one. The selective hydrogenation may be effected with hydrogen and a pre-reduced catalyst such as palladium on a carrier; the selective hydrolysis may be achieved with acid; and the final oxidation may be performed under Oppenauer conditions, which may be modified by using p-benzo-quinone as hydrogen acceptor. Detailed examples are provided. Specification 887,861 is referred to. Reference has been directed by the Comptroller to Specifications 870,286 and 884,544.