Abstract

SYNTHESIS, CHARACTERIZATION AND ANTI-TUBERCULAR SCREENING OF SOME SUBSTITUTED 5-ETHOXY BENZIMIDAZOLE DERIVATIVES

Dr. Sunila T. Patil* and Dr. Sunil P. Pawar

ABSTRACT

Benzimidazole derivatives are very useful compound with well known biological activity. Notable among these are antimicrobial, anti-tubercular, antimalarial, anti-inflammatory, anticancer, antiviral, antiprotozoal, antihistaminic, antioxidant and anthelmintic actions.. In the current research work, the title compounds 5-ethoxy-2-substituted benzimidazole, were synthesized by nitration of phenacetin with concentrated nitric acid it gives N-(2-nitro-5-ethoxyphenyl) acetamide (I). Compound (I) on reduction with alcohol gives 5-ethoxy-2-nitroaniline (II). Reaction of compound (II) with hydrazine hydrate produced 5-ethoxy ortho phenylene diamine(III). The reaction of compounds (III) with substituted acids yielded the corresponding 5 ethoxy-2-substituted benzimidazole (IV). The identification and characterization of the synthesized compounds were carried out by Elemental analysis, melting point, Thin Layer Chromatography, FT-IR, NMR and Mass data to ascertain that all synthesized compounds were of different chemical nature than the respective parent compound. The compounds were screened out for anti-tubercular activity. The anti-tubercular activity of compounds were done by using Microplate Alamar Blue Assay (MABA). The test compounds IVa, IVb and IVc showed significant anti-tubercular activity against H37RV strain of Mycobacterium tuberculosis. The minimum inhibitory concentration (MIC) values were found in the range of 0.8 to 12.5 μg/ml compared with the standard drugs Pyrazinamide, Streptomycin and Ciprofloxacin.

Keywords: Anti-tubercular activity, Mycobacterium tuberculosis, Benzimidazole, Pyrazinamide, Streptomycin, Ciprofloxacin.