Development for an efficient synthesis method of 2'-deoxyguanosine-C8 adducts with several amino/nitro-arenes

Heterocyclic amines (HCAs) are mutagenic compounds present in cooked meat and fish, and some of them are known to be carcinogenic. DNA adduct formation is now believed to be the initial critical step for carcinogenesis. HCAs are metabolically activated to form predominantly 2'-deoxyguanosine-C8 adducts (dG-C8 adduct) where the exocyclic N atom of activated compounds are covalently bound to the C8 position of dG. In order to prepare a high yield of dG-C8 adducts with HCAs, we tried to adapt the Buchwald-Hartwig arylamination reaction using 8-bromo-dG derivatives and HCAs. With the combined use of xantphos and Cs2CO3, we successfully obtained coupling compound derived from a carcinogenic HCA, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) at a 97% yield. Subsequent deprotection may lead to authentic dG-C8 adducts of several HCAs.