Physical properties disaccharides

The side chains in the latter are flexible disaccharides on account of poor-quality diffraction patterns, their tentative molecular structures are known only from computer modeling.1" On the other hand, well-defined crystal structures are available for gellan and welan, and they can be correlated with the physical properties of the polysaccharides the details are presented here. Their conformation angles are listed in Table VI. 

It was shown from data summarized previously that telomerization of butadiene can occur with a large range of alcohols including reduced saccharides as well as mono- and disaccharides. It is of interest to extend such a reaction to much more complicated substrates such as polysaccharides (21) (Fig. 14). In that case, a low degree of substitution (average number of ether chains per glucose unit) is sufficient to modify deeply the physical properties of the organic polymer [51]. 

Naturally occurring oligosaccharides including disaccharides and trisaccharides have attracted enormous attention in the last few years. Multidisciplinary efforts of biochemists and medicinal chemists have led to new developments [1,2,3,4,5] in the field, which are based primarily on the phenomenal physical properties such as stability, crystallinity, and solubility. Chemical properties include selective reactivity towards various reagents such as oxidative and reducing agents and this has opened up new possibilities for functionalization and derivatization of value-added oligo- and polysaccharides. 

Among other physical properties of the above-mentioned classes of disaccharides, one of the particularly important properties is Raman optical activity (ROA). 

The conformational studies and physical properties of tetrasaccharides along with representative examples of disaccharides and O- and Al-olrgosaccharides have been reported by Meyer [65]. 

Two monosaccharides may be combined with the loss of one molecule of water to form a disacchaiide. Polysaccharides and other complex carbohydrates are then produced by the condensation of more monosaccharide subunits with the loss of a molecule of water for each additional monosaccharide. Depending upon its constitution, hydrolysis of a polysaccharide yields either a single monosaccharide or a mixture of monosaccharides. In this chapter, some of the fundamental chemical and physical properties of carbohydrates will be investigated using simple mono-and disaccharides several classic qualitative tests to characterize and classify carbohydrates will also be performed. 

This chapter is exclusively devoted to the occurrence, significance and physical and randomly selected chemical properties of various group of disaccharides, trisaccharides, tetrasaccharides, pentasaccharides and hexasaccharides. 

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