The C6 configuration and syn/anti conformational preference of the bisulfite adducts of deoxyuridine and deoxycytidine by NMR and DFT calculations

The configuration at C6 of the epimeric bisulfite adducts of deoxyuridine was determined by means of NMR in conjunction with DFT calculations. The preferred conformations of the products were examined and it was found that the (6R)- and (6S)-epimers adopted predominantly different conformations—syn and anti, respectively, for the orientation of the base with respect to the ribose ring. Similar results were obtained for deoxycytidine. It was concluded that the chemical shifts of the anomeric H1′ protons alone are sufficient for the configurational and conformational determination of other pyrimidine nucleotide congeners.

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