Glucose polysaccharides containing, formation

PROBLEM 22.44 When D-glucose, or any polysaccharide containing D-glucose units such as cellulose, is pyrolyzed with an acid catalyst, a new compound, levoglucosan (1), is formed. Write a mechanism for the formation of 1 from D-glucose under these conditions. 

In the literature, there are several examples of partial hydrolysis of polysaccharides or glycoconjugates containing 2-amino-2-deoxyhex-ose residues. One example is the hydrolysis of carboxyl-reduced, N deacetylated chondroitin, with the formation of 4-0-(2-amino-2-deoxy-/3-D-galactopyranosyl)-D-glucose.51 Another is the isolation of 6-0-(2-amino-2-deoxy-/8-D-galactopyranosyl)-D-galactose after N-de-acetylation and partial hydrolysis of the pentasaccharide (19) obtained... 

Subsequently, Ordin and Hall (25, 26) found that particulate preparations from oat coleoptiles could use UDP-D-glucose as substrate for polysaccharide formation. Upon degradation of the polysaccharide derived from UDP-D-glucose with impure cellulase, cellobiose, and to a lesser extent a substance identified as a trisaccharide containing mixed / -(1 - 4), / -(1 - 3) glucosyl linkages were obtained. 

This chapter begins with a discussion of the structure and stereochemistry of monosaccharides. Then the formation of cyclic structures front monosaccharides is discussed. This is followed by the presentation of a small number of reactions of these compounds. The classic series of experiments that was used to establish the structure of glucose is presented next. Finally, the structures of disaccharides, polysaccharides, and a few other types of carbohydrate-containing compounds are introduced. 

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