Azasteroids. Part IX. Synthesis of (±)-13-aza-15-thia-18-norequilenin and a study of Bischler–Napieralski cyclisation of N-acyl-2-(1-naphthyl)ethylamines

Abstract
It is shown that benz[f]isoquinolines can be readily obtained by Bischler–Napieralski cyclisation of N-acyl derivatives of 2-(1-naphthyl)ethylamines. Tricyclic imines obtained by this route, on reaction with mercapto-acetic acid led to (±)13-aza-15-thia-18-norequilenin and its deoxy analogue. Structure of these heterosteroids was established by n.m.r. spectroscopy.