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

The 13 C 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 CH 2 OH substituent at C-5 with CH 3 , CO 2 H, CO 2 Me, 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 13 C 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 13 C signals of structurally related methyl aldofuranosides.