Guaran structure

Guaran. Principal polysaccharide from endosperm of guar seeds, Cyamopsis tetragonaloba (L.) Taub., Legumi-nosae Heyne, Whistler, J. Am. Chem. Soc. 7, 2249 (1948). Structure Whistler, Durso, ibid. 74, 5140(1952). Configuration Koleske, Kurath, J. Polymer Sci. Pt. A, 2, 4123... 

A complete list of semi-synthetic heparinoids is outside the scope of this article. Products of sulfation of neutral polysaccharides include sulfates of starch, cellulose, - - xylan, dextran, " guaran, and synthetic polymers of o-glucose. A somewhat closer simulation of the structure of heparin was attempted by sulfating polysaccharides containing amino sugars or uronic acids or both, such as chitin and chitosan, " and the corresponding N-formyl, N-(car-boxymethyl), O-(carboxymethyl), and 5-carboxylated - deriva-... 

Methylation of the polysaccharide with subsequent hydrolysis and separation of products leads to the isolation (1) of 2,3,4,6-tetra-O-methyl-D-galactose, 2,3,6-tri-0-methyl-l>-mannose, and 2,3-di-0-methyl-l>-mannose. These results, confirmed by others (11) f show that D-galactopyranose units occur as nonreducing terminal units. Since the branches must be short, the most likely structure of guaran, based on evidence to this point, is that shown. 

Most other galactomannans, and particularly locust bean gum, possess molecular structures similar to guaran hence their important hydrophilic and colloidal properties are also understandable. 

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