Carbon-13 NMR investigation of some substituted 1,3-thiazolidin-4-ones

The 13C NMR spectra of a series of 2,3-diaryl-1,3-thiazolidin-4-ones were measured and the resonance signals produced by the methylene, methine and carbonyl groups of the heterocyclic ring assigned. The variations in their chemical shifts were examined and the influence of S-oxidation was investigated. 3-Benzyl-2-phenyl-1,3-thiazolidin-4-one, 3-butyl-2-phenyl-1,3-thiazolidin-4-one and 2,3-diphenyl-5-methyl-1,3-thiazolidin-4-one were also examined, the last compound being shown to exist as a mixture of isomers. T1 relaxation times were determined for three thiazolidinones and related to structural effects.