Synthesis of substituted imidazo[5,1-b]benzimidazoles
By the cyclization of the formyl and acetyl derivatives of 2-(α-aminoethyl)-1-methylbenzimidazole under the action of phosphorus oxychloride we have synthesized, respectively, 3,4-dimethyl- and 1, 3, 4-trimethylimidazo[5, 1-b]benzimidazoles. 2-(α-Aminoethyl)-1-methylbenzimidazole was obtained by reducing the oxime of 2-acetyl-1-methylbenzimidazole. The latter was synthesized from 1-methylbenzimidazole by an organolithium synthesis.