Abstract

SYNTHESIS, CHARACTERIZATION & BIOLOGICAL EVALUATION OF SOME NEWER BENZIMIDAZOLE DERIVATIVES

Ankit* and Nitin Mittal

Abstract

Benzimidazole derivatives play important role in medical field with so many Pharmacological activities such as antimicrobial, antiviral, antidiabetic and anticancer activity. The potency of these clinically useful drugs in treatment of microbial infections and other activities encouraged the development of some more potent and significant compounds. Benzimidazoles are remarkably effective compounds, extensive biochemical and pharmacological studies have confirmed that these molecules are effective against various strains of microorganisms. Firstly o-phenylenediamine was condensed with 3- hydroxy benzoic acid in the presence of 4N HCl to give 3-(1Hbenzo[ d]imidazole-2-yl) phenol. In the second step, 3-(1Hbenzo[ d]imidazole-2-yl) phenol was reacted with HBr in the presence of ZnCl2 to give 2-(3-bromophenyl)-1H-benzo[d]imidazole. In the third step, 2-(3-bromophenyl)-1H-benzo[d]imidazole was reacted hydrazine hydrate and finally reacted with substituted benzaldehyde to give benzimidazole derivatives (4a-4i). The resultant products (4a-4i) have consistent values of C, H and N contents with predicted structure. The structures of newly synthesized benzimidazole derivatives were accomplished through IR, 1HNMR and mass spectral data. All the newer Benzimidazole derivatives were evaluated for antibacterial action with respect to the mentioned species: the strain of Gram +ve bacteria includes B. subtilis, S.aureus and the strains of Gram –ve incorporates P.aeruginosa, E.coli and antifungal action with respect to Aspergillus niger and Candida albicans species of fungi. The antibacterial information shows that compounds containing nitro and methoxy substitution were more potent and the antifungal information recommend that compounds having methoxy were most active.

Keywords: Benzimidazole, Antifungal, antimicrobial, Synthesis.