Azasteroids. Part VIII. Synthesis and stereochemistry of (±)-13-aza-18-norequilenin

Abstract

A total synthesis of (±)-13-aza-18-norequilenin has been achieved. Condensation of 2-(6-methoxy-1-naphthyl)-ethylamine (IV) and β-methoxycarbonylpropionyl chloride gave an amide (V) which on Bischler–Napieralski reaction followed by reductive cyclisation afforded the methyl ether of the title compound. The same product could be obtained in a single step by reaction of the amine (IV) with α-oxoglutaric acid. The structure of this azasteroid has been fully confirmed by spectroscopic methods. In its n.m.r. spectrum the two C-12 geminal protons appear 1·5 p.p.m. apart from which a semi-chair conformation for ring C is inferred.