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A series of N-substituted benzimidazole derivatives (1-5) was synthesized. Benzimidazole nucleus was acylated in 1-position with benzoyl chloride in basic medium at room temperature to form N-acylated benzimidazole (1). Reaction of the N-acylated benzimidazole (1) with different amines yields the desired N-substituted benzimidazole derivatives (2-5). All the synthesized compounds (1-5) were evaluated in vivo for analgesic activity by acetic acid induced writhing and hot plate tests in mice. In comparison to the standard drug aspirin at the same dose (50mg/kg), compound 4 was the most potent as it decreased the number of writings to 17% comparing to control. However, aspirin resulted in a decrease equal to 12% of the control. In addition, all the test compounds except 5 produced some reduction in reaction time for hot plate test. Markedly, the effect was statistically significant with compounds 3 and 4.