Polysaccharides amino sugar derivatives

In tandem with his studies of polysaccharides, Stacey had a research group investigating the chemistry of the unusual sugars found as components of carbohydrate macromolecules. In this context, derivatives of simple sugars, di- and trisaccharides, uronic acids, deoxy sugars, amino sugars, sugar sulfates, and phosphates were studied. 

The generic term monosaccharide (as opposed to oligosaccharide or polysaccharide) denotes a single unit, without glycosidic connection to other such units. It includes aldoses, dialdoses, aldoketoses, ketoses and diketoses, as well as deoxy sugars and amino sugars, and their derivatives, provided that the parent compound has a (potential) carbonyl gTOup. 

Pneumococcus, polysaccharides from, 6-7 Poly(a-L-guluronic acid), 353, 355-356,415 Poly(P-D-mannuronic acid), 353-354,414 Polysaccharides, 311 -439 amino sugar derivatives, 166 chemical repeating units, 321, 324-325... 

Amino sugars are components of antibiotic substances109 and bacterial polysaccharides,1,0 and are therefore of interest. The nucleoside antibiotics amicetin, bamicetin, and plicacetin contain, as the sugar residue, a monoaminopentadeoxy disaccharide that is closely related to maltose. In view of the reported antibiotic and antitumor properties of these pyrimidine nucleosides,111,112 the synthesis of aminodeoxy derivatives of maltose would be of interest. 

An analogous reaction of UDP-2-acetamido-2,6-dideoxy-D-xy/o-hexos-4-ulose (7d) results in formation of the derivatives of 2-acetamido-2,6-dideoxy-D-glucose and -D-galactose.166 These amino sugars were identified as components of several O-specific polysaccharides (for reviews, see Refs. 95 and 167). 

Transamination reactions on keto sugars allow the introduction of amino groups as seen in the amino sugars glucosamine and galac-tosamine (Figure 8.10). These compounds, as their N-acetyl derivatives, are part of the structures of several natural polysaccharides, and... 

Figure 1.20 Some derivatives of monosaccharides and amino sugars commonly found in polysaccharides...

Here we discuss new types d cellulose derivatives synthesized by nucleophilic substitution of mixed polysaccharides containing repeating units of 2,3- and 3,6-anhydro sugars, units d amino sugars, their N-alkyl(aryl)- and N-carboxylalkyl(aryl) derivatives, alkyl derivatives and phenylbarenyl derivatives d deoxygliux)se, elimination reactions of unsaturated derivatives containing multiple C-C bonds in the... 

In contrast, two neutral amino acids can make only two different dipeptides an acidic and a basic amino acid can make only four different dipeptides. There are about 20 different common monosaccharides (including the amino sugars, uronic acids, and other derivatives). Thus, the potential for variability among polysaccharides is even greater than that of proteins. However, almost all polysaccharides found in nature are composed of repeating units of fewer than 5 different monosaccharides. 

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