Synthesis and Invitro Anti-Inflammatory Activity of Some 1, 2-Disubstituted Benzimidazoles

Fused heterocyclic compound, Benzimidazole formed by fusion of benzene and imidazole. Often the benzo derivative of imidazole is referred to as benzimidazole. Although it is the commonest name of the parent compound of the series, other names such as benzimidazole and 1, 3-benzodiazole are often used have wide range of diverse therapeutic applications. The synthesis of substituted benzimidazole derivatives thought remarkably effective compounds as anti-ulcers, anti-cancers, anti-malarials, anti-convulsants, anti-virals, anti-fungal and much more which have been reported in literature. A practical and convenient synthetic method which has been developed for the facile synthesis of 1, 2-disubstituted benzimidazoles is reported in the paper. The method described has the benefits of operational simplicity, excellent yields, and high chemo selectivity. In this present study, in the first step, 2-substituted benzimidazoles were synthesized which have been prepared by reaction of o-phenylenediamine with various carboxylic acids in presence of suitable solvent. Later, in the second step, the formed 2-substituted benzimidazoles reacts with chloroacetyl chloride in presence of base gives desired title compounds of 1, 2-disubstituted benzimidazole derivatives. All the structures of synthesized compounds have been purified by recrystalisation and thin layer chromatography which were further elucidated by elemental analysis, IR and ¹H NMR spectral data. All the four synthesized compounds have been screened for their invitro anti-inflammatory activity using HRBC membrane stabilization method by comparing with standard drug Diclofenac sodium in the concentrations of 25 μg/mL, 50 μg/mL and 100 μg/mL. All the tested compounds exhibit significant invitro anti-inflammatory activity when compared with standard drug.