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 microbial resistance has become a global hazard with the irrational use of antibiotics. Infection of drug-resistant 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 synthesized compounds were characterized by IR, 1H NMR and MS. The antibacterial test in-vitro showed that all of the synthesized compounds had 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.