Synthesis And Antimicrobial Activity Evaluation Of Novel 4-Thiazolidinones Containing A Pyrone Moiety

A series of thiosemicarbazones 3a-d and 4-thiazolidinones 5a-d, 7a-d, and 9a-h were synthesized and evaluated for their in vitro antimicrobial activity. Condensation of 3-acetyl-4-hydroxy-6-methyl-2H pyran-2-one1 (dehydroacetic acid) with thiosemicarbazide 2a-d in ethanol at room temperature yielded the thiosemicarbazones 3a-d. These compounds were exploited to synthesize the 4-thiazolidinones 5a-d via their reactions with ethyl 2-bromo propionate4. Derivatives 7a-d were prepared by reaction of the thiosemicarbazones 3a-d with phenyl bromoacetate 6. The 4-thiazolidinones 9a-h were obtained by treatment of compound 3a or 3c with maleimide derivatives 8a-d in refluxing ethanol, under sulfuric acid catalysis. All compounds were screened in vitro for their antibacterial and antifungal activities against five human pathogens microorganisms: Escherichia coli ATCC 25992, Pseudomonas aeruginosa ATCC 27852, Staphylococcus aureus ATCC 43300, Staphylococcus aureus ATCC 25923, and Candida albicans.