Synthesis and evaluation of the antimicrobial activities of 3-((5-phenyl-1,3,4-oxadiazol-2-yl)methyl)-2-thioxothiazolidin-4-one derivatives.

Two novel series of 3-((5-phenyl-1,3,4-oxadiazol-2-yl)methyl)-2-thioxothiazolidin-4-one derivatives were designed and synthesized, and their anti-bacterial activities evaluated. These compounds showed broad-spectrum inhibitory activities against both Gram-positive and Gram-negative bacteria with minimum inhibitory concentration (MIC) values in the range of 1-64 μg/mL. The activity of compound 6c was the more potent with MIC values of 1 μg/mL against the MRSA (3167 and 3506) strains than those of gatifloxacin, oxacillin, and norfloxacin. Compared to the previously reported rhodanine derivatives, 2-thioxothiazolidin-4-one derivatives exhibited an inhibition against Gram-negative strains due to the introduction of a 1,3,4-oxadiazole moiety, among which compounds 3 showed moderate activities against the Gram-negative bacteria (Escherichiacoli 1924) with MIC values of 16 μg/mL.