Synthesis and in-vitro antibacterial activity of 5-substituted 1-methyl-4-nitro-1H-imidazoles

A series of 5-substituted 1-methyl-4-nitro-1H-imidazole derivatives were synthesized and evaluated for in-vitro antibacterial activity against a panel of microorganisms including Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, Klebsiella pneumonia, Enterobacter aerogenes, and Helicobacter pylori using conventional agar dilution method. Among the test compounds, 1-methyl-4-nitro-5-(phenylsulfonyl)-1H-imidazole was the most potent against Gram-positive bacteria, with a MIC value of < or =8 microg/mL. All compounds showed no significant activity against Gram-negative bacteria at concentrations < or =64 microg/mL. The MIC values against 15 clinical isolates of H. pylori indicated that compounds 10 and 11 were the most active compounds in this series in terms of inhibiting the growth of H. pylori (MIC = 2 microg/mL). It was also demonstrated that their corresponding activities were four times larger than that of metronidazole.