Design, synthesis and antimicrobial activities evaluation of Schiff base derived from secnidazole derivatives as potential FabH inhibitors

FabH, β-ketoacyl-acyl carrier protein (ACP) synthase III, is critically important to the initiation of fatty acid biosynthesis and is highly conserved among Gram-positive and Gram-negative bacteria. A series of novel secnidazole derivatives (1-20) were synthesized and fully characterized by spectroscopic methods and elemental analysis. Among these compounds, 6, 8, 11, 13, 14, 16-20 were reported for the first time. These compounds were tested for antibacterial activities against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. The compounds inhibitory assay and docking simulation indicated that compound 20 (E)-2-(2-methyl-5-nitro-1H-imidazol-1-yl)-N′-(3,4,5-trimethylbenzylidene)acetohydrazide with MIC of 3.13-6.25 μg/mL against the tested bacterial strains was a potent inhibitor of Escherichia coli FabH.