Synthesis of oligodeoxynucleotides containing 6-N-([13C]methyl)adenine and 2-N-([13C]methyl)guanine

Abstract

Oligonucleotides containing 6-N-([¹³C]methyl)adenine and 2-N-([¹³C]methyl)guanine have been prepared for NMR studies using the deprotection step to introduce the [¹³C]methylamine group. For this purpose, the use of 2′-deoxy-6-O-(pentafluorophenyl)inosine 1 and 2′-deoxy-2-fluoro-6-O-[2-(4-nitrophenyl)ethyl]inosine 2 as precursors of the N-methylated nucleosides is described. Preliminary NMR characterization of the ¹³C-labelled oligonucleotides shows that the ¹³C chemical shift of the methyl group in N-methylguanine is sensitive to duplex formation, making it a useful local probe.