Hydrogenation on palladium-containing granulated catalysts 3. Synthesis of aminobenzimidazoles by catalytic hydrogenation of dinitroanilines

Efficient hydrogenation of o-aminonitrobenzenes on palladium-containing granulated carbon catalysts in carboxylic acid solutions was accompanied by cyclization into aminobenzimidazoles. A simple hydrogenation reactor with a fixed gauze holding a reusable granulated catalyst was designed. Acylated and sulfonylated 4(7)-aminobenzimidazoles were obtained. In terms of electronic and geometrical parameters, they are close analogs of biologically active imidazo[1,5,4-e,f ][1,5]benzodiazepines. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1171–1181, June, 2007.