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.

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► 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.