DETERMINATION OF PROTON-PROTON DISTANCES IN 2-ACETAMIDO-2-DEOXY MONOSACCHARIDES FROM H-1-NMR RELAXATION MEASUREMENTS IN SOLUTION

Determination of selective and biselective H-1 spin-lattice relaxation rates combined with steady-state and transient H-1-H-1 NOE data allowed calculation of intramolecular proton-proton distances in 2-acetamido-2-deoxy-D-glucosides (1a and 1b), 2-acetamido-2-deoXy-D-mannoses (5a and 5b) and their acetylated derivatives. These measurements were supplemented by DESERT studies using derivatives selectively labeled by H-2 at position 2. These distance data are in good correlation with literature values obtained by X-ray crystallography. Interproton distance measurements allow the determination of relative configurations, including that of the anomeric carbon, in hexopyranose rings in cases where other methods, like those based on scalar coupling constants, fail.