ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Benzimidazole. I. Synthesis of 1-aryl-5-aminobenzimidazole

R. Kada, A. Hulka, A. Jurášek, and J. Štetinová

Slovak Technical University, Bratislava

Abstract: The prepn. of some new 1-aryl-5-nitrobenzimidazoles and their redn. products, 1-aryl-5-aminobenzimidazoles, was described. 1-Substituted-5-nitrobenzimidazoles were prepd. by the cyclization of the corresponding 2-amino-4-nitro-4'-X-substituted-diphenylamine with HCO₂H in the presence of 4N HCl. The redn. of the nitro compds. was carried out with SnCl₂.2H₂O and HCl in glacial AcOH. The yields of 1-substituted-5-aminobenzimidazoles were from 55 to 60%. The following were prepd.: 2,4-dinitro-4'-(diethylamino)diphenylamine, black, m. 143-4.5°; 2-amino-4-nitro-4'-bromodiphenylamine, m. 152-3°; 2-amino-4-nitro-4'ododiphenylamine, m. 159-60°; 2-amino-4-nitro-4';-(diethylamino)diphenylamine, m. 144-5°; 1-(4'-X-substituted-phenyl)-5-nitrobenzimidazole, with X = Br, m. 258-9°, X = I, m. 196-7°, X = OEt, m. 178-80°, X = NEt2, m. 182-3°, and 1-(4'-Y-substituted phenyl)-5-aminobenzimidazole, with Y = Cl, m. 123-4°, Y = Br, m. 128-30°, Y = I, m. 152°, Y = OMe, m. 122-3°, Y = OEt, m. 130-1°, and Y = NEt2, m. 175-6°.

Full paper in Portable Document Format: 207a550.pdf (in Slovak)

Chemical Papers 20 (7) 550–554 (1966)