J(77Se,1H) and J(77Se,13C) couplings of seleno‐carbohydrates obtained by 77Se satellite 1D 13C spectroscopy and 77Se selective HR‐HMBC spectroscopy

Abstract

Seleno-carbohydrates are those in which the oxygen of the glycosidic bond or the hydroxyl group is artificially replaced with selenium. This substitution changes 1 H and 13 C chemical shifts and produces spin coupling constants involving 77 Se. Coupling constants, such as 2-3 J(77 Se, 1 H), are likely to be useful for conformational analyses of glycans because such couplings are never observed in natural glycans. Several papers have discussed the relationship between 2-3 J(77 Se, 1 H) and conformation; however, only few reports describe 1-3 J(77 Se, 13 C), which could also be useful. Here, we obtain 77 Se coupling constants of seleno-carbohydrates from 77 Se-selective HR-HMBC and 77 Se satellites in 1D 13 C spectra and examine their conformations using the Newman projection scheme.