First, the covalent bond between the leaving group (L) and the
anomeric carbon atom should possess a moderate thermal stability, because the use of an unstable glycosyl donor often results in difficulty in its handling as well as low reaction yields.
79) exhibited HMBC correlations with
anomeric carbon at 104.
The presence of the PAE resin seems to greatly influence the relaxation of the
anomeric carbon, thereby yielding more of those species and longer relaxation times for the rapidly relaxing components.
It is also observed that the region above 100ppm is narrower and lower than in the spectra of the other two samples, which could be due to the change at its
anomeric carbon.
Electronegative substituents at the C-2 position of saturated heterocycles or at the
anomeric carbon of a pyranose ring favor the equatorial position much less than expected; often the axial position is favored.
Sucrose is a nonreducing disaccharide composed of glucose and fructose linked via their
anomeric carbons.
20) confirmed by two
anomeric carbons ([delta]CI' 103.