PREPARATION AND NMR-STUDIES OF PYRUVIC-ACID AND RELATED ACETALS OF PYRANOSIDES - CONFIGURATION AT THE ACETAL CARBON-ATOMS

Stereoisomeric pairs of pyruvic acid and related acetals linked to the 3,4- and 4,6-positions, respectively, of the anomeric methyl d-galactopyranosides and the corresponding acetals linked to the 4,6-positions of the anomeric methyl d-glucopyranosides have been prepared by conventional methods, and their structures have been assigned. Their 1H- and 13C-n.m.r. spectra have been recorded. The differences in chemical shifts obtained for stereoisomeric pairs of acetalic CH3 groups are of sufficient magnitude to make possible the unequivocal determination of the stereo-chemistry of pyruvic acid acetals in naturally occurring polysaccharides. © 1979.