Patent ID: 6583298
Filing Date: 2003-06-24
Classification: C07J

Abstract:
Process for the synthesis of 17&bgr;-hydroxy-17&agr;-methyl-2-oxa-5&agr;-androstane-3-one of the formula (I) characterised by transforming the 17&bgr;-hydroxy-17&agr;-methyl-1,3-seco-2-nor-5&agr;-androstane-1,3-diacid of formula (III) into the ring-closed 17&bgr;-hydroxy-17&agr;-methyl-1,3-seco-2-norâˆ’5&agr;-androstane-1,3-diacid anhydride of formula (II) in an inert solvent or without solvent with a C2-C3 alkane acid anhydride or a substituted carbodiimide of formula R1â€”N&boxH;C&boxH;Nâ€”R2â€” wherein R1 and R2 independently are C1-C6 alkyl group, C1-C6 alkyl group substituted by tertiary or quaternary amino group or 1-3 phenyl group, C5-C6 cycloalkyl group, aryl group substituted by 1-3 methoxy, tertiary-amino, nitro, C1-C4 alkyl group or 1-3 halogen atomâ€”and regioselectively reducing it by a complex alkali metal hydride in an inert solvent.