Comparative ~1H NMR study of hydroxy protons in galabioside and its S-linked 4-thiodisaccharide analogue in aqueous solution

摘要

The NMR data obtained from hydroxy protons have been used to investigate the presence and absence of intramolecular hydrogen bonding in aqueous solutions of 2-(trimethylsilyl) ethyl galabioside (#delta#-D-Galp-(1 -> 4)-#beta#-D-Galp-O(CH_2)SiMe_3) and the S-linked 4-thiodisaccharide analogue. The data show that there is a weak hydrogen bond interaction between O-6H and O-2'H in galabioside, but not in the thio-analogue. The results are in good agreement with those reported for the substances in a Me_2SO-d_6 solution. It is also shown that the existence of a hydrogen bond can be quite easily monitored by comparing the NMR data of the hydroxy protons.