Design and Synthesis of Some Thiazolidin-4-ones Based on (7-Hydroxy-2-oxo-2H-chromen-4-yl) Acetic Acid

(7-Hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid methyl ester(1) upon reaction with ethyl bromoacetate furnishes (7-ethoxycarbonylmethoxy-2-oxo-2H-chromen-4-yl)-acetic acid methylester (2), which on treatment with 100% hydrazine hydrate yields (7-hydrazinocarbonylmethoxy-2-oxo-2H-chromen-4-yl)-acetic acid hydrazide (3). The condensation of compound 3 with different aromatic aldehydes afforded a series of [7-(arylidenehydrazinocarbonylmethoxy)-2-oxo-2H-chromen-4-yl]-acetic acid arylidene-hydrazide Schiff’s bases 4a-k. Cyclo-condensation of compounds 4a-k with 2-mercapto-acetic acid in N,N-dimethylformamide in the presence of anhydrous ZnCl2 affordsN-(2-aryl-4-oxothiazolidin-3-yl)-2-(4-(2-aryl-4-oxothiazolidin-3-ylcarbamoyl)-methyl)-2-oxo-2H-chromen-7-yloxy)-acetamides 5a-k. Structure elucidation of the products has been accomplished on the basis of elemental analysis, IR, 1H-NMR and 13C-NMR data. Compounds 4a-k and 5a-k will be screened for their antibacterial activity against both Gram-positive and Gram-negative bacteria and the results reported elsewhere in due course.