Glycosides determination

Gaffield, W., Circular dichroism, optically rotatory dispersion and absolute configuration of flavanones, 3-hydroxyflavanones and their glycosides. Determination of agyclone chirality in flavanone glycosides, Tetrahedron, 26, 4093, 1970. 

Gaffield W (1970) Circular Dichroism, Optical Rotatory Dispersion and Absolute Configuration of Flavanones, 3-Hydroxyflavanones and their Glycosides Determination of Agly-cone Chirality in Flavanone Glycosides. Tetrahedron 26 4093... 

Figure 27.13 Monosaccharides commonly found in oligosaccharide chains in glycoproteins and glycosidic determinants of blood groups.

This reaction has been used m an imaginative way to determine the ring size of glycosides Once all the free hydroxyl groups of a glycoside have been methylated the glycoside is subjected to acid catalyzed hydrolysis Only the anomeric methoxy group IS hydrolyzed under these conditions—another example of the ease of carbocation for matron at the anomeric position... 

The use of penodic acid oxidation m structure determination can be illustrated by a case m which a previously unknown methyl glycoside was obtained by the reaction of D arabmose with methanol and hydrogen chlonde The size of the nng was identified as five membered because only one mole of penodic acid was consumed per mole of glycoside and no formic acid was produced Were fhe nng six membered fwo moles of penodic acid would be required per mole of glycoside and one mole of formic acid would be produced... 

It was of interest to determine whether glycosides of 6-deoxy-D-xylo-hex-5-enopyranose were susceptible to enzyme hydrolysis by / -glucosi-dase. Since aromatic glucosides are hydrolyzed by this enzyme at a much faster rate than aliphatic glycosides, phenyl 6-deoxy-/ -D-rt/Zo-hex-5-enopyranoside (18) was prepared (20). Phenyl / -D-glucopyranoside was converted to the 6-tosylate by selective esterification and then, by conventional procedures, transformed to phenyl 2,3,4-tri-0-acetyl-6-deoxy-... 

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