Synthesis of novel 4-thiazolidinone derivatives <i>via</i> one-pot three-component reaction of maleimide, thiosemicarbazide, and Meldrum’s acid

The synthesis of novel thiazolidinone derivatives via the three-component reaction has been developed involving the reaction of thiosemicarbazide with maleimide and Meldrum’s acid in a single pot. Optimization of reaction conditions was studied with different solvents and quantities of raw materials. The optimum results were obtained when the reaction was carried out in the ratio (2:2:1 mmol) of maleimide, thiosemicarbazide, and Meldrum’s acid, in the presence of two drops of triethylamine in ethanol. The products were formed with good yields with a significant decrease in reaction time. The structures of thiazolidinones were elucidated by 1H, 13C NMR, FT-IR spectroscopy, HRMS, and X-ray diffraction.</p

Synthesis and Antimicrobial Activity Evaluation of Novel 4-Thiazolidinones Containing a Pyrone Moiety

<div><p></p><p>A series of thiosemicarbazones <b>3a–d</b> and 4-thiazolidinones <b>5a–d, 7a–d,</b> and <b>9a–h</b> were synthesized and evaluated for their in vitro antimicrobial activity. Condensation of 3-acetyl-4-hydroxy-6-methyl-2<i>H</i> pyran-2-one<b>1</b> (dehydroacetic acid) with thiosemicarbazide <b>2a–d</b> in ethanol at room temperature yielded the thiosemicarbazones <b>3a–d</b>. These compounds were exploited to synthesize the 4-thiazolidinones <b>5a–d</b> via their reactions with ethyl 2-bromo propionate<b>4</b>. Derivatives <b>7a–d</b> were prepared by reaction of the thiosemicarbazones <b>3a–d</b> with phenyl bromoacetate <b>6</b>. The 4-thiazolidinones <b>9a–h</b> were obtained by treatment of compound <b>3a</b> or <b>3c</b> with maleimide derivatives <b>8a–d</b> in refluxing ethanol, under sulfuric acid catalysis. All compounds were screened in vitro for their antibacterial and antifungal activities against five human pathogens microorganisms: <i>Escherichia coli</i> ATCC 25992, <i>Pseudomonas aeruginosa</i> ATCC 27852, <i>Staphylococcus aureus</i> ATCC 43300<i>, Staphylococcus aureus</i> ATCC 25923, and <i>Candida albicans.</i></p> </div