Issue 0, 1982

Determination of the anomeric configuration in glycosides of 3-deoxy-2-aldulosonic acids by circular dichroism and X-ray crystallography

Abstract

Methyl (methyl 3-deoxy-D-arabino-2-heptulopyranosid)onate was obtained by acid-catalysed esterification and glycosidation of the free 2-aldulosonic acid. The molecular geometry of the glycosidic ester was determined by X-ray crystallography, and indicated both that the molecule was the α-anomer and that the ring oxygen and the carboxy-group were very nearly coplanar. The c.d. spectrum showed a negative n π* transition band centred at 224 nm. The c.d. spectra of a number of methyl glycopyranosides derived from 6-, 7-, and 8-carbon 3-deoxy-2-aldulosonic acids demonstrated that all the compounds believed to be α-glycosides had negative maxima, and all those believed to be β-glycosides had positive maxima around 220 nm independent of their 2C5 or 5C2 conformation. The only known furanoside, believed to be a β-anomer, also had a positive maximum. The chirality of the anomeric carbon atom of this class of compound can thus be conveniently established by determining the sign of the Cotton effect at 220 nm.

Article information

Article type
Paper

J. Chem. Soc., Perkin Trans. 1, 1982, 3055-3063

Determination of the anomeric configuration in glycosides of 3-deoxy-2-aldulosonic acids by circular dichroism and X-ray crystallography

D. Charon, L. Szabó, M. Cesario and J. Guilhem, J. Chem. Soc., Perkin Trans. 1, 1982, 3055 DOI: 10.1039/P19820003055

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