Syntheses and 1H- and 13C-nuclear magnetic resonance spectra of all positional isomers of methyl mono-O-tetradecanoyl-.ALPHA.- and .BETA.-D-glucopyranosides.

All the isomers of the mono-O-myristoyl derivative of methyl α- and β-D-glucopyranosides were unambiguously prepared, and their 1H- and 13C-NMR spectra are discussed in relation to the stereochemistry of the pyranose ring and ester grouping. The acylation shifts on introducing a myristoyl group at each carbon atom of the pyranose ring in the acyl derivatives were tabulated and were shown to be additive parameters for diacyl derivatives. A diacyl mixture obtained by direct acylationof methyl β-D-glucopyranoside could be completely analyzed by 13C-NMR. The effects of orientational differences of an anomeric methoxyl group on pyranose carbon shielding were also clarified in every mono-O-myristoyl-D-glucopyranoside. An anomalous effect at C2 of the 2-O-acyl derivative is suggested to originate from a conformational change of the ester group in the β-anomer.