Synthesis and antimicrobial evaluation of 5-aryl-1,2,4-triazole-3-thione derivatives containing a rhodanine moiety

Three series of 5-aryl-1,2,4-triazole-3-thione derivatives containing a rhodanine moiety (5a–k, 6a–i, and 7a–i) have been synthesized, characterized and evaluated for their antibacterial activity. Some of these displayed potent antibacterial activity against several Gram-positive and Gram-negative bacterial strains (including multidrug-resistant clinical isolates) with minimum inhibitory concentration (MIC) values in the range of 4–64 μg/mL and minimum bactericidal concentration (MBC) values in the range of 8–256 μg/mL. Compared with previously reported rhodanine derivatives, these compounds exhibited a broad spectrum of antibacterial activity by means of introducing 4-amino-5-aryl-1,2,4-triazole-3-thione moiety. Notably, compound 5f exhibited good antibacterial activity against Staphylococcus aureus RN 4220, S. aureus 209, S. aureus 503, Gram-negative bacteria (Escherichia coli 1924), and Candida albicans 7535 with MBC values of 8 or 16 μg/ml. All of the compounds synthesized in the current Letter were characterized by 1H NMR, 13C NMR, infrared and mass spectroscopy.

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