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Abstract

The invention relates to a new process for the synthesis of 17.beta.-hydroxy-17.alpha.-methyl-2-oxa-5.alpha.-androstane-3-one of formula (I). The process according to the invention is as follows: the 17.beta.-hydroxy-17.alpha.-ethyl-1,3-seco-2-nor-5.alpha.-androstane-1,3-diacid of formula (III) is transformed into the ring-closed 17.beta.-hydroxy-17.alpha.-methyl-1,3-seco-2-nor-5.alpha.-androstane-1,3-diacid anhydride of formula (II) in an inert solvent or without solvent with a C.sub.2 -C.sub.3 alkan acid anhydride or a substituted carbodiimide of formula R.sup.1 --N.dbd.C.dbd.N--R.sup.2 -- wherein R.sup.1 and R.sup.2 independently are C.sub.1 -C.sub.6 alkyl group, C.sub.1 -C.sub.6 alkyl group substituted by tertiary or quaternary amino group or 1-3 phenyl group, C.sub.5 -C.sub.6 cycloalkyl group, aryl group substituted by 1-3 methoxy, tertiary amino, nitro, C.sub.1 -C.sub.4 alkyl group or 1-3 halogen atom--and the obtained compound of formula (II) is reduced regioselectively by a complex alkali metal hydride in an inert solvent The new 17.beta.-hydroxy-17.alpha.-methyl-1,3-seco-2-nor-5.alpha.-androstane-1,3-diacid anhydride of formula (II) is also the subject of the invention. ##STR1##

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First Claim