Conformational and Spectral Investigations of Thiazolidinone Derivatives by 1H and 13C NMR Spectroscopy

The magnetic non-equivalence of isomeric proton and 13C nuclei has been investigated on rotational isomers of 3-aryl-2,4-thiazolidinediones and 3-aryl-2-arylimino-4-thiazolidinones. The detection of magnetic non-equivalence for proton nuclei was better in quinoline solutions. Free energies of activation have been estimated. The varying hetero atom in the hetero ring, in comparision to earlier data1-3, is seen to effect the additive shift parameters and the shielding of distant aryl carbon bonded to hetero ring.