Preparation and heteronuclear 2D NMR spectroscopy of a DNA dodecamer containing a thymidine residue with a uniformly 13C-labeled deoxyribose ring.

[13C5]-2-Deoxy-D-ribose, synthesized from [13C6]-D-glucose (98% 13C), was coupled with thymine to give [1',2',3',4',5'-13C5]-thymidine (T) in an 18% overall yield. The thymidine was converted to the 3'-phosphoramidite derivative and was then incorporated into a dodecamer 5'-d(CGCGAATTCGCG)-3' by solid-phase DNA synthesis. Preparation of 0.24 mumole of the labeled dodecamer, which is sufficient for a single NMR sample, consumed only 25 mg of glucose. By virtue of the 13C labels, all of the 1H-1H vicinal coupling constants in the sugar moieties were accurately determined by HCCH-E.COSY.