Microwave assisted three component reaction conditions to obtain new thiazolidinones with different heterocyclic skeletons.

Taking into account previous results studied in our research group in the synthesis of 4-thiazolidinones selectively by a three-component reaction, we present here a new proposal for the “one pot” generation of new 4-thiazolidinones through a multicomponent reaction using aromatic and heteroaromatic amines, ethanol as a “green” solvent in order to minimize the environmental impact, and modifying the aldehyde group in the glycosidic residue, synthesized from D-mannitol. In the first place 1,2:5,6-di-O-isopropylidene-D-mannitol is obtained and then, the oxidative cleavage with NaIO₄ gives 2,3-O-isopropiliden-D-glyceraldehyde. Thus, the new stereocenters in the target molecule may have an amplifying effect of the biological activity and reducing cytotoxicity. The study is focused in the variation of the irradiation times (period of 5, 10 and 30 minutes) and the concentration of thioglycolic acid (1 to 10 equivalents) in order to study the possibility of controlling the structure and / or stereochemistry of the products formed in the reaction. Thiazolidinones are obtained with a 62-95% yield for 30 minutes as the maximum time reaction. The generation of the corresponding intermediates and reaction products were monitored by TLC and CG-MS, taking reaction aliquots. The characterization of the intermediates and corresponding products were performed by ¹H-, ¹³C, DEPT and HSQC- NMR spectroscopy.