Further Studies on the Assignment of Signals in 13C Magnetic Resonance Spectra of Aldoses and Derived Methyl Glycosides

Abstract

The 13C signals of most of the more common sugars and their methyl glycosides have been assigned, based on the α-carbon and β-carbon effects that occur on deuterium substitution. For pyranoses having the same hydroxyl configuration, replacement of the CH2OH substituent at C-5 with CH3, CO2H, CO2Me, or H is accompanied by displacement of the C-4, C-5, and when applicable C-6 signals. The magnitudes of the displacements in the glucopyranose and mannopyranose series are almost identical and were of aid in assigning signals in the 13C spectrum of methyl (methyl α-D-mannopyranuronosid)uronate. The displacements, however, differ from corresponding ones observed in the galactopyranose series. Some assignments are made for the 13C signals of structurally related methyl aldofuranosides.