Radiolytic hydroxylation of 1-substituted thymines promoted by transition metal salts in N2- and N2O-saturated aqueous solutions.

The effect of high-valent transition metal salts on the radiation-induced hydroxylation of thymine (1a), 1-methylthymine (1b), and thymidine (1c) to the corresponding thymine glycol derivatives (2a-c) was studied at pH 7.0 in N2- and N2O-saturated aqueous solutions. The selectivities of (2a-c) based on converted (1a-c) increased to attain the maxima of 35-69% and then decreased, with increasing the one-electron reduction potential [E(M (n+1)+/Mn+)] of metal salts in the range of 0-1.0 V vs. NHE less than. Metal salts with E(M (n+1)+/Mn+) 0 or greater 1.0 V vs. NHE caused little change in the yields of (2a-c).