Synthesis and solution conformation studies of the modified nucleoside N4,2′-O-dimethylcytidine (m4Cm) and its analogues Original Research Article

The dimethylated ribosomal nucleoside m4Cm and its monomethylated analogues Cm and m4C were synthesized. The conformations (syn vs anti) of the three modified nucleosides and cytidine were determined by CD and 1D NOE difference spectroscopy. The ribose sugar puckers were determined by the use of proton coupling constants. The position of modification (e.g., O vs N methylation) was found to have an effect on the sugar pucker of cytidine.