Substituent effect in photocatalytic oxidation of 2-oxo-1,2,3,4-tetrahydropyrimidines using TiO2 nanoparticles

The semiconductor-sensitized oxidation of various 1-, 4- and 5-substituted 2-oxo-1,2,3,4-tetrahydropyrimidines was carried out in acetonitrile using TiO2 anatase nanoparticles. The aims of this study were to elucidate the effects of the nature of the substituents on the 1-, 4- and 5-positions of the heterocyclic ring, the type of the photocatalyst and the nature of solvent on the rate of reaction. The proposed electron-transfer mechanism is supported by the experimental results and also by the computational studies.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (102 K)Download as PowerPoint slideHighlights► Photooxidation of 2-oxo-1,2,3,4-tetrahydropyrimidines was investigated by TiO2 anatase nanoparticles. ►The nature of the heterocyclic ring substituents influences the rate of reaction. ►Drastic effect is observed by the substitution on the N1 of the heterocyclic ring. ► Experimental and theoretical results support the proposed electron-transfer mechanism. ►The nature of solvent affects the rate of reaction.