Novel efficient synthesis of 3,4-dihydro-6-substituted-3-phenylpyrimidin-2(1H)-ones

Photolysis (λ = 254 nm) of 4-allyltetrazolones in alcoholic solutions produces stable 3,4-dihydro-6-substituted-3-phenylpyrimidin-2(1H)-ones in nearly quantitative yields.