Deep Eutectic Solvent (DES) Mediated Multicomponent Synthesis of 4- thiazolidinone-5-carboxylic Acid: A Green Chemistry Approach

Background: The 4-thiazolidinone-5-carboxylic acid and its derivatives have diverse applications in agriculture, industrial and pharmaceutical fields. Therefore, the synthesis of this heterocyclic compound attracted much attention from researchers with green chemistry protocols. In this research work, we have introduced the green protocol for the synthesis of 4-thiazolidinone- 5-carboxylic acid by keeping the parameters in mind like cost-effective, environmentally benign, short reaction time and easy work-up procedure. Methods: Initially, we irradiated the mixture of substituted aldehyde, thiosemicarbazide and furan 2-5-dione in the presence of choline chloride-thiourea-based Deep Eutectic Solvent (DES) as a green medium. The reaction optimization was performed in different solvents like ethanol, glycerol, and PEG-400. Results: The DES, which was used as a green solvent, produced an excellent result in context to short reaction time, yield, easy workup, mild reaction condition and cost-effective protocol. All the results are discussed. Conclusion: The DES-mediated synthesis of 4-thiazolidinone-5-carboxylic acid is found to be an excellent protocol, which followed green chemistry principles. This method has specific features like mild reaction conditions, environmentally benign, cost-effective and easy workup procedure.