Photocatalytic oxidation of dihydropyrimidinones using titanium dioxide suspension

Photocatalytic oxidation has been used for the oxidation of some ethyl 3,4-dihydropyrimidin-2(1H)-one-5-carboxylates to their corresponding ethyl pyrimidin-2(1H)-one-5-carboxylates using a TiO2/O-2 system under UV irradiation by a 400 W high pressure mercury lamp in acetonitrile. The results revealed that the order of photocatalytic activity for photooxidation was TiO2 (anatase) > TiO2 (rutile). The effects of some other physicochemical parameters such as amount of photocatalyst, pH, solvent and time of irradiation were studied. The pyrimidinones were attained from the related dihydropyrimidinones after 2-4.5 h. The results showed the photo stability of this type of compound.