Analysis of oligosaccharide conformation by NMR spectroscopy utilizing H-1,H-1 and H-1,C-13 residual dipolar couplings in a dilute liquid crystallinephase

A novel procedure for determining H-1,H-1 NMR dipolar couplings in a dilute liquid crystalline medium based on H-1,H-1 COSY spectroscopy and a J-doubl ing procedure is presented. Subsequent conformational analysis of the centr al region of a partially deuterated decasaccharide employing H-1,H-1 and H- 1,C-13 dipolar couplings, H-1.H-1 nuclear Overhauser effect spectroscopy, a nd computer modeling is described. In particular, the use of H-1,H-1 dipola r couplings is of paramount importance in deriving a three-dimensional stru cture of the decasaccharide.