Synthesis of (1-15N)-labeled 2'-deoxyinosine and 2'-deoxyadenosine

A reaction between 2'-deoxyinosine and 1-N-(4-nitrophenyl) derivative results in the formation of (1-15N)-2'deoxyinosine in three steps with 48% yield. The 1-N and 6-N positions are suitable for 15N-labeling because they are involved in Watson-Crick adenine-thymine base pairing in duplex DNA. The 4-nitrophenyl motif is a suitable electron-withdrawing group to initiate the synthesis of the above-mentioned nucleotide.