Heterocyclic mesomeric betaines. Part 2. Synthesis of a hetero derivative of the benzo[b]phenalenide anion

Abstract

Reductive cyclization of 2,4-dimethyl-8-(2-nitrophenyl)quinoline with hot triethyl phosphite afforded 2,4-dimethyl-7H-pyrido[3,2-c]carbazole (10) and 4,6-dimethyl-6aλ⁵,7-diazabenz[de]anthracen-6a-ium-7-ide (4; R = Me). The latter is the first example of a conjugated heterocyclic mesomeric betaine isoconjugate with the benzo[b]phenalenide anion.