Cyclised products in the synthesis of 6-substituted phenanthridines by phenolic cyclisation

Abstract

Phenolic cyclisation of 2-(3-hydroxyphenyl)cyclohexylamine (15) with aromatic aldehydes gave 6-aryl-1,2,3,4,4a,5,6,10b-octahydrophenanthridin-7-ols (3) and (4) cyclised at the ortho-position to the hydroxy-group together with the usual 9-hydroxy-derivatives (5), (6), and (7); compounds (3), (5) and (6) were also synthesised by Bischler–Napieralski reaction of the benzamide (23) of 2-(3-methoxyphenyl)cyclohexylamine, followed by reduction and demethylation. Moreover, the reaction of (15) with six aliphatic ketones gave the corresponding 6,6-disubstituted phenanthridines.