Carbon-13 nuclear magnetic resonance: naturally occurring nucleosides.

The natural-abundance carbon-13 nuclear magnetic resonance spectra of the naturally occuring pyrimidine and purine nucleosides have been determined and completely analyzed. The carbon-13 chemical shifts obtained provide information on the electronic structure and qualitatively at least correlate well with the known chemical reactivity of these molecules. The carbon-13 shifts are in general far more informative than proton shifts for structural analysis of the nucleosides.