Reaction of pyrido[1,2-a]benzimidazole and tetrahydropyrido[1,2-a]benzimidazole with acetylenedicarboxylic ester

Previously unknown polynuclear condensed systems with bridgehead nitrogen atoms have been obtained by treating acetylenedicarboxylic ester with pyrido[1,2-a]-benzimidazole and tetrahydropyrido[1,2-a]benzimidazole. © 1986 Plenum Publishing Corporation.