Microwave-Assisted Synthesis of Some New Benzimidazole Derivatives with their Antimicrobial Activity

Abstract

2-(2-Chlorobenzyl)-1H-benzimidazole (2) was prepared from the reaction of o-phenylenediamine and ethylimido- o-chlorophenylacetate hydrochloride (1) under microwave irradiation. The acetate and hydrazide derivatives of 2- (2-chlorobenzyl)-1H-benzimidazole (2) were synthesized respectively. Then, 2-[2-(2-chlorobenzyl)-1H-benzimidazol-1- yl]-N-(2,5-dioxopyrrolidin-1-yl)acetamide (5), 5-{[2-(2-chlorobenzyl)-1H-benzimidazol-1-yl]methyl}-1,3,4-oxadiazole- 2-thiol (6), acetohydrazide (7a-i) and N-phenylhydrazinecarbo thioamide derivatives (8a-c) were synthesized from hydrazide derivatives. Finally, the intramolecular cyclization of N-phenylhydrazinecarbo thioamide derivatives (8a-c) gave the corresponding 1,2,4-triazole-3-thione derivatives (9a-c). The newly synthesized compounds have been tested for their antimicrobial activity against three Gram-positive and three Gram-negative bacterias. Keywords: 1, 2, 4-Triazole, antimicrobial activity, benzimidazole, imine function, iminoester hydrochloride, microwave synthesis, oxadiazole.