Synthesis and solution conformation studies of the modified nucleoside N-4,2 '-O-dimethylcytidine (m(4)Cm) and its analogues

The dimethylated ribosomal nucleoside m(4)Cm and its monomethylated analogues Cm and m(4)C 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 modi. cation (e. g., O vs N methylation) was found to have an effect on the sugar pucker of cytidine. (C) 2008 Elsevier Ltd. All rights reserved.