Rosenthal I, Sasson S, Elad D
Nucleic Acids Res. 1978 Apr;5(4):1297-300. doi: 10.1093/nar/5.4.1297.
5, 6-Dihydropyrimidines can be oxidized photochemically to the original pyrimidines with light of lambda greater than 300 nm in the presence of transition metal salts which act as sensitizers. A hydrogen atom abstraction by hydroxyl radical is suggested as the reaction mechanism.