Synthetic studies on 5-(3,4-dimethoxyphenyl)-5,6-dihydrophenanthridin-6-ol,an analogue of perloline

Abstract

Two independent syntheses of the title compound (2), an analogue of perloline, are described. 9-(3,4-Dimethoxyphenyl)fluoren-9-ol reacted with hydrazoic acid in polyphosphoric acid to give 6-(3,4-dimethoxyphenyl)phenanthridine, the N-oxide of which was photolysed to 5-(3,4-dimethoxy-phenyl)phenanthridin-6-one (8) which was reduced to the title compound directly with sodium bis(2-methoxyethoxy)aluminium hydride ('Redal'), or by reduction to 5-(3,4-dimethoxypheny1)-5,6- dihydrophenanthridine followed by oxidation with N-bromosuccinimide. The phenanthridinone (8) was also synthesized by photolysis of the nitrone of 3,4-dimethoxy-N-fluorenylideneaniline.