Synthesis of substituted derivatives of imidazo [5, 1-b] benzimidazole

Heating, either molten or in high-boiling solvents, 1-methyl-2-[(N-phenylthiocarbamoyl)amino] (pyrid-4-yl)-methylbenzimidazole, or refluxing with phosphorus oxychloride in benzene acyl derivatives of 1-methyl-2-[(pyrid-4-yl)(amino)]- and 1-methyl-2 [(phenyl)(amino)]-methylbenzimidazoles, gives the corresponding derivatives of the imidazo [5, 1-b] benzimidazole system, hitherto undescribed in the literature.