Remarkable promation of the hydroxylation of thimine to give thimine glycol with almost complete depression of side reactions by 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TMPO·) derivatives was observed in the γ-radiolyses of the N 2-and N 2 O-saturated aqueous solutions. In the O 2-saturated solution, TMPO· depressed the thymine conversion close to the level under N 2 while promoted the formation of thymine glycol to some extent by ...