A 13C NMR study on the interactions of calcium chloride/potassium chloride with pyranosides in D2O

The 13C NMR spectra of methyl β-d-glucopyranoside, methyl β-d-galactopyranoside, methyl β-d-xylopyranoside, and methyl β-l-arabinopyranoside were recorded in CaCl2/KCl + D2O mixtures and in D2O. The chemical shifts of C-1, C-3, and C-5 in the methyl β-d-glucopyranoside and methyl β-d-galactopyranoside decrease rapidly as molalities of CaCl2/KCl increase, while those of C-1, C-2, and C-3 in the methyl β-d-xylopyranoside and methyl β-l-arabinopyranoside decrease rapidly as molalities of CaCl2/KCl increase. Cations (Ca2+/K+) can weakly complex with O in OMe of the pyranosides studied. Results are discussed in terms of the stereochemistry of the pyranoside molecules and the structural properties of the ions.

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