No abstract

EPR spectroscopy has been employed to study the reactions of SO,'-and OH' radicals with xanthine, %methylxanthine, hypoxanthine and 2-hydroxypurine. from one-electron oxidation of either the parent compound or its anion, followed by deprotonation. For xanthine and 8-methylxanthine the respective radical anion and radical dianion were observed, for hypoxanthine the species detected correspond to the neutral radical and radical anion, whereas for 2-hydroxypurine only its radical anion was observed.12.1 k 0.5, respectively, whereas the pKa value of the hypoxanthine neutral radical was 7.7 k 0.1. Radicals obtained on the reaction of SO,'-with these hydroxypurines resulted, depending on the pH, The pKa values of the radical anion of xanthine and 8-methylxanthine were estimated as 12.0 k 0.1 and In the reaction with OH', only the radical anion of xanthine was detected. Paper 5/07893H