Facile Synthesis of Some New Pyrazole-Based 2-Thioxo-4-thiazolidinone

Compound 3 condensed with different aromatic aldehydes 6a–d in ethanol in the presence of a few drops of piperidine to give the corresponding Schiff’s bases 7a–d . On the other hand, compound 3 reacts with o-hydroxybenzaldehyde derivatives 8a and 8b in refluxing ethanol catalyzed by a few drops of piperidine to yield 1H-inadzolyl-2-thioxo-4-thiazolidinones 9a and 9b .

Reaction of compound 3 with α-ketoesters 10a and 10b or α-diketones 10c–e in refluxing glacial acetic acid furnished the pyrazolyl-2-thioxo-4-thiazolidinone derivatives 11a–e . Also, compound 3 reacts with some different enaminones 12a–f in refluxing glacial acetic acid to afford the new pyrazolyl-2-thioxo-4-thiazolidinone derivatives 13a–f . Pyrazoles 15a–d was obtained via reaction of compound 3 with chalcones 14a–d in dimethylformamide (DMF).