Facile synthesis of novel benzotriazole derivatives and their antibacterial activities

A series of benzotriazole derivatives (compounds 1–27) were synthesized, and 24 (compounds 1–5, 9–27) of which were first reported. Their chemical structures were confirmed by means of (1)H NMR, IR and elemental analyses, coupled with one selected single crystal structure (compound 1). All the compounds were assayed for antibacterial activities against three Gram positive bacterial strains (Bacillus subtilis, Staphylococcus aureus and Streptococcus faecalis) and three Gram negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa and Enterobacter cloacae) by MTT method. Among the compounds tested, most of them exhibited potent antibacterial activity against the six bacterial strains. Most importantly, compound 3-benzotriazol-1-yl-1-(4-bromo-phenyl)-2-[1,2,4]triazol-1-ylpropan-1-one (19) showed the most favourable antibacterial activity against B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. coli and E. cloacae with MIC of 1.56 µg/mL, 1.56 µg/mL, 1.56 µg/mL, 3.12 µg/mL, 6.25 µg/mL and 6.25 µg/mL, respectively.