Thiazolidine-2,4-dione in benzoylation reaction

The direction of the benzoylation reaction of thiazolidine-2,4-dione under the conditions of basic and general acid catalysis was studied. It was shown that the direction of benzoylation of thiazolidine-2,4-dione at the cyclic nitrogen atom or oxygen atoms depends on two major factors: the solvent and the presence of cations. A nonpolar solvent and triethylamine direct the reaction toward the formation of the dibenzoyl product, which was isolated and characterized for the first time. The structure of this compound has been unambiguously identified using NMR and X-ray diffraction analysis. A hydrogen bond between the nitrogen atom of the dibenzoyl product and the proton of the chloroform molecule was found in crystal structure.