Oxidative damage of pyrimidine nucleosides by the environmental free radical oxidant NO 3 • in the absence and presence of NO 2 • and other radical and non-radical oxidants

Abstract

Analysis of the products formed in the reaction of the environmental free radical oxidant NO 3 • with permethylated uridine 1 and thymidine 2 in solution revealed highly complex reaction pathways following initial NO 3 • induced oxidative electron transfer at the pyrimidine ring. Product formation was found to depend not only on the nature of the nucleobase, but also on the presence of other free radical oxidants, namely NO 2 •. In the reaction of 1 with NO 3 •, which was generated through CAN photolysis, apart from formation of the highly oxidized nucleoside derivative 4 as the major product, cleavage of the CN glycosidic bond did also occur, resulting in formation of ribolactone 5 and the ..