New syntheses of DNA adducts from methylated anilines present in tobacco smoke

A new synthetic pathway for the formation of deoxyguanosine-monoarylamine adducts is described, involving the generation and use of arylnitrenes as electrophilic synthons. Photolysis of aryl azides, the most common method for generating arylnitrenes, was tested in the presence of 2'-deoxyguanosine. N-(2'-Deoxyguanosin-8-yl)monoarylamine (dG-C8-Ar) adducts were obtained, but the yields were typically low. Deoxygenation of nitro- and nitrosoarenes by triethyl phosphite in the presence of 2'-deoxyguanosine proved to be an effective method, by which dG-C8-Ar, (2'-deoxyguanosin-N1-yl)monoarylamine (dG-N1-Ar), and (2'-deoxyguanosin-O(6)-yl)monoarylamine (dG-O(6)-Ar) adducts were obtained in acceptable yields.