Theoretical and experimental studies on methyl α-d-glucopyranoside derivatives

Theoretical quantum mechanical calculations using density functional theory (DFT) at the B3LYP level have been carried out for synthesized esterified methyl α-d-glucopyranoside derivatives. The predicted NMR characteristics obtained with GIAO method are compared with 1H, 13C and 31P experimental NMR data, whereas calculated vibrational frequencies have been confronted with experimental Raman spectra. This comparison has permitted to state that the compounds under investigation do not occur in the form of a zwitterion but in the neutral form as well as to determine the most favourable stereoisomer.