Selective functionalization at N-position of guanine in oligonucleotides via reductive amination.

Chemo- and site-specific modifications in oligonucleotides have wide applicability as mechanistic probes in chemical biology. However, methods that label specific sites in nucleic acids are scarce, especially for labeling DNA/RNA from biological or enzymatic sources rather than synthetic ones. Here we have employed a classical reaction, reductive amination, to selectively functionalize the N-amine of guanosine and 2'-deoxyguanosine monophosphate (GMP/dGMP).