Synthesis of 9-Deaza-2\u27-deoxyguanosine, an analogue of 8-Oxo-2\u27-deoxyguanosine

The DNA base 2\u27-deoxyguanosine (dG) is susceptible to oxidation by reactive oxygen species that are formed in cells during biological processes as well as exposure to radiation. This oxidation causes the formation of the modified nucleotide 8-oxo-2\u27-deoxyguanosine (OdG). OdG can form base pairs with both dC and dA, whereas unmodified dG forms base pairs with only dC. Forming a base pair with dA can lead to dG to dT transversions, possibly explaining the link between OdG and aging and diseases such as cancer. OdG differs from dG at both the N7 and C8 positions, both of which are thought to contribute to the promiscuous base pairing of OdG. Analogues of OdG differing from OdG at only one position allows for the study of more specific reasons why OdG can form the base pairs that it does. To gain further insight into the exact role of the N7 and C8 positions in OdG base pairing, the OdG analogue 9-deaza-2\u27­ deoxyguanosine (CdG), which retains an N7-hydrogen (similar to OdG) but lacks a CS-oxygen (dissimilar to OdG), was synthesized and modified for incorporation into DNA