Tetracyclic heteroaromatic systems. Part-II. benzimidazo [1, 2-a] benzimidazoles

Benzimidazo [1, 2-a] benzimadozoles [1, R=H] were synthesized by the trialkylphosphite-induced deoxygenation and thermolysis of 1-0-nitrophenyl and 1-0-azidophenyl benzimidazole. Spectral and other properties of the product and the intermediate compounds are reported