Synthesis and Antibacterial Evaluation of (S,Z)-4-methyl-2-(4-oxo-5- ((5-substituted phenylfuran-2-yl) methylene)-2-thioxothiazolidin-3-yl) Pentanoic Acids

The resistance of antimicrobials has become a global hazard with the irrational use of antibiotics. Infection of drug-resistance bacteria seriously threatens human health. Currently there is an urgent need for the development of novel antimicrobial agents with new mechanisms and lower levels of toxicity. In this paper, a series of (S,Z)-4-methyl-2-(4-oxo-5-((5-substitutedphenylfuran-2-yl) methylene)-2-thioxothiazolidin-3-yl)pentanoic acids via a Knoevenagel condensation were synthesized and evaluated for their antibacterial activity in vitro. The compounds synthesized were characterized by IR, 1H NMR and MS. The antibacterial test in vitro showed that all of the synthesized compounds showed good antibacterial activity against several Gram-positive bacteria (including multidrug-resistant clinical isolates) with minimum inhibitory concentration (MIC) values in the range of 2–4 µg/mL. Especially compounds 4c, 4d, 4e and 4f were the most potent, with MIC values of 2 µg/mL against four multidrug-resistant Gram-positive bacterial strains.