SELECTIVE SITE DEUTERATION ON THE SUGAR RING AS AN EFFICIENT MARKER OF CONFORMATION IN NUCLEOSIDES - THE C-D STRETCHING MODE OF THE (2'-R)-[2'-H-2]-2'-DEOXYURIDINE AND ITS 1,3,3-TETRAISOPROPYLDISILOXAN-1,3-DIYL)-DERIVATIVE

A uridine specifically deuterated on the deoxyribose ring at the C2', and the same compound in a more rigid form, due to a chemically fused ring (between C3' and C5'), have been synthesized. By NMR, the couplin g constants J1'-2' and J3'-4' have been determined and the populations of the C2'-endo and C3'-endo conformers have been deduced for the two compounds. Comparison of these results with an FTIR and Raman study o f the stretching mode nuC-D on the C2' site allows a specific assignme nt of each observed band to one of the two classes of conformers. This enables us to consider the further step: the direct recognition, by I R and Raman spectroscopies, of the local conformation at a specific si te of a synthetic oligonucleotide, using the nuCD signals as marker ba nds.