Disaccharides with free hemiacetal group

Carb-36.3. Disaccharides with a free hemiacetal group... 

Synthesis of disaccharides is possible using the protecting group methods discussed earlier (Fig. 22.43). We can use the free alcohol of one monosaccharide to link with the hemiacetal of a protected second monosaccharide. The acetate-... 

In the nomenclature of oligosaccharides, trivial names are still used for a number of substances (e.g. maltose, cellobiose or trehalose. Figure 4.5). In the case of reducing disaccharides, systematic nomenclature takes as its basis the name of the monosaccharide with a free hemiacetal hydroxyl group, which is preceded by the name of the substituted monosaccharide and the respective anomeric configuration is indicated (a- or P-). Disaccharide maltose (Figure 4.5), formed by condensation of... 

In addition, the corresponding isomers with the a-glycosidic linkage are possible. The free hydroxyl group of the hemiacetal of a disaccharide cannot be assigned to a configuration the a- and /3-form are in equilibrium. The first two disaccharides listed are of the trehalose type the rest, of the maltose type. 

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