The lack of robust, high-throughput, and sensitive analytical strategies that can conclusively map the structure of glycans has significantly hampered progress in fundamental and applied aspects of glycoscience. Resolution of the anomeric α/β glycan linkage within oligosaccharides remains a particular challenge. Here, we show that "memory" of anomeric configuration is retained following gas-pha...

nbo analysis, hybrid density functional theory (b3lyp/6-311+g**) and ab initio molecular orbital (hf/6-311+g**) based methods were used to study the anomeric effects (ae), electrostatic interactions, dipole-dipole interactions and steric repulsion effects on the conformational properties of 2-methoxy- (1), 2-methylthio- (2), 2-methylseleno- (3), 2-fluoro- (4), 2-chloro- (5) and 2-bromocyclohexa...

Oxazinane rings can undergo isomerization or transformation to 5-membered tuned by the anomeric effect.

The use of thioglycosides and other glycan derivatives with anomeric sulfur linkages is gaining increasing interest, both in synthesis and in various biological contexts. Herein, we demonstrate the occurrence and circumvention of anomerization during 1-S-glycosylation reactions, and present highly efficient and stereocontrolled syntheses of a series of photoprobe-thiosaccharide conjugates. Muta...

A variable temperature-dependent H NMR conformational analysis of JHH coupling constants and NOE enhancements of a series of 8-aza-3-deaza modified guanine nucleosides 2 and 4–8 has been performed in DMSO-d6 and the results compared to those for natural nucleosides dG (1) and G (3). 8-Aza-3-deaza nucleobase modification leads to the stabilization of N-type conformers by ∆∆H of 3.1 kJ mol , whic...

Carbohydrates are an extremely complex group of isomeric molecules that have been difficult to analyze in the gas phase by mass spectrometry because (1) precursor ions and product ions to successive stages of MS(n) are frequently mixtures of isomers, and (2) detailed information about the anomeric configuration and location of specific stereochemical variants of monosaccharides within larger mo...

Partially protected monosaccharides with free anomeric hydroxyl groups are useful in the synthesis of oligosaccharides [ l-31. A number of chemical methods are reported to remove the anomeric acyl group of peracylated carbohydrates [ 4-61, providing a useful route to partially protected saccharides [ 7,8]. Enzymatic reactions have also been used for this purpose [ 9-231. According to previous r...

The possible involvement of mutarotases in glucose metabolism has been studied by examining the anomeric specificities of a number of glycolytic enzymes. Hexokinases from yeast or Ehrlich ascites tumor cells showed only a marginal preference for the cx anomer of glucose. (All configurations, unless otherwise specified, refer to the D configuration of glucose and its derivatives.) The K, values ...

Abstract Based on structures determined by X-ray crystallography, ab initio MP2 calculations type A mesoionic rings give geometries in good agreement with observed values. study of four ring systems, each exocyclic oxygen, nitrogen or carbon groups, shows that the presence and configuration lone pairs significantly influences geometry configurational preference. Using a localised bond model NBO...

The block-localized wave function (BLW) method, which can derive optimal electron-localized state with intramolecular electron delocalization completely deactivated, has been combined with the polarizable continuum model (PCM) to probe the variation of the anomeric effect in solution. Currently both the hyperconjugation and electrostatic models have been called to interpret the anomeric effect ...