10.1021/jo9012805
The research aims to study the reactivity of RNA radicals, specifically the 5,6-dihydrouridin-6-yl radical, using photochemical methods. The study employs Norrish type I photocleavage of the tert-butyl ketone (2b) to generate the 5,6-dihydrouridin-6-yl radical (1b) and investigates its reactivity under aerobic and anaerobic conditions. Key chemicals used include ?-mercaptoethanol as a trapping agent, benzoyl groups for enhanced detection via HPLC, and various ribonucleoside derivatives as precursors and product standards. The study finds that the radical can be cleanly generated with high mass balances, and its reactivity is similar to but slightly less than that of its 2'-deoxyribonucleoside analogue. The major product formed in the presence of O2 is 5'-benzoyl-6-hydroxy-5,6-dihydrouridine (6), while under anaerobic conditions, dihydrouridine (4) is the primary product. The study concludes that the 5,6-dihydrouridin-6-yl radical is a useful model for studying RNA radical chemistry and its potential role in oxidative RNA damage.