SYNTHESIS, ANTIBACTERIAL, AND ANTIFUNGAL ACTIVITIES OF SOME NEW BENZIMIDAZOLES

1,2-Diaminobenzimidazoles 2 were synthesized by N-amination of 2-aminobenzimidazoles 1 with hydroxylamine-O-sulphonic acid. Substituted 1-alkyl and 1-alkylarylbenzimidazoles 3 were prepared from various benzimidazoles by alkylating with the corresponding alkyl halides. As an example, 1-(4-chlorobenzyl)-5,6-dimethylbenzimidazole (3(4)) was N-aminated with O-(mesitylenesulphonyl)-hydroxylamine to give 5,6-dimethyl-1-(4-chlorobenzyl)-3-aminobenzimidazolium mesitylenesulphonate (6). Compounds 4, 7 and 5 are derivatives of 1,2-(5-nitro-2-furfurylideneamino)-benzimidazoles and were synthesized by the carbonyl-amine condensation of 5-nitro-2-furaldehyde with appropriate 1,2-diamino-benzimidazoles 2 and 2-aminobenzimidazoles 1 and 3, respectively. An attempt to prepare the derivative of 3-(5-nitro-2-furfurylidenamino)-benzimidazolium mesitylenesulphonate (8) from compounds 6 was unsuccessful. The antimicrobial activities of the above compounds were screened against different strains of bacteria and fungi. The general structure-activity relationships of tested benzimidazoles 3-7 were determined.