Process for the preparation of steroidal 17.alpha.-arylcarboxylates
申请人:Schering Corporation
公开号:US04323512A1
公开(公告)日:1982-04-06
17-Arylcarboxylate esters of 9,11-unsubstituted 4-pregnene-17.alpha.,21-diol-3,20-diones are prepared by reaction of the corresponding 17.alpha.-hydroxy derivative with alkyl lithium and an anhydride or acyl halide reagent in the presence of 4-(di-lower alkyl)aminopyridine at low temperatures. A preferred mode of the process is the preparation of 16.beta.-methyl-1,4-pregnadiene-17.alpha.,21-diol3,20-dione 17.alpha.-m-iodobenzoate 21-benzoate, a valuable intermediate in the manufacture of betamethasone.