Glucurone trimethyl

Synthesis of Uronic Acids. Part II. 2 3 4-Trimethyl Derivatives of Mannuronic, Glucuronic, and Galacturonic Acids, F. Smith, M. Stacey, and P. I. Wilson, J. Chem. Soc., (1944) 131-134. 

In a recent paper650 the relationships between Rhizobium radicicolum polysaccharides and those of pneumococcus are indicated by crossprecipitin reactions of the former with Types III and VI anti-pneumococcus horse sera. In addition, hydrolysis of the methylated polysaccharide of Rhizobium radicicolum yields equal amounts of 2,3,6-trimethyl-D-glucose, 2,3-dimethyl-D-glucose and 2,3-dimethyl-D-glucuronic acid.65 1 The minimum trisaccharide repeating unit consists, in part, of cello-biuronic acid, and may be represented ... 

Reeves and Goebel72 have shown that hydrolysis of the reduced methylated capsular polysaccharide of Type III pneumococcus yields 2,3,6-trimethyl-D-glucose and the anomeric forms of methyl 2,4-dimethyl-D-glucoside. The cellobiuronic acid units in the polysaccharide are thus linked through position 3 of the D-glucuronic acid residue, probably by /3-D-linkages. That is, the polysaccharide contains alternate 1,3-and l,4-/3-D-linkages. 

Catalytic reduction and methanolysis of the methylated capsular polysaccharide of Type III pneumococcus gives a mixture of methyl 2,3,6-trimethyl- and 2,4-dimethyl-a/3-D-glucopyranosides. The latter, which arises from glucuronic acid units in the polysaccharide, can be separated into crystalline a- and 6-isomers identical with synthetic specimens.84,88... 

The same procedure has revealed that the aldobionic acid obtained from damson gum and cherry gum by acid hydrolysis has the structure V. Methylation gives the methyl ether VI and when this is subjected to hydrolysis with dilute mineral acid there results 3,4,6-trimethyl-D-mannose (VII) and 2,3,4-trimethyl-D-glucuronic acid (VIII). 

On the assumption that methylation of the degraded arabic acid was complete, the location of hydroxyl groups in the various cleavage fragments indicates the positions through which the monosaccharide units are involved in union with the other residues. Thus the isolation of three molecular proportions of 2,3,4-trimethyl-D-glucuronic acid (VIII) and one molecular proportion of 2,3,4,6-tetramethyl-D-galactose (XI)... 

An examination of the methanolysis products of methylated mesquite gum has revealed that they consist of five substances, of which the following four have been identified 2,3,5-trimethyl-L-arabinose (XXV), 3,5-dimethyl-L-arabinose (XL), 2,4-dimethyl-D-galactose (XXI) and 2,3,4-trimethyl-D-glucuronic acid (VIII). 

In model experiments,205 it was found that concentration of an aqueous solution of the aldonic acids in the presence of hydrochloric acid gives exclusively the 1,4-lactones, which, on subsequent trimethyl-silylation, give only one peak on the chromatogram. This method was successfully employed for the separation of D-galacturonic, D-glucuronic, and D-mannuronic acids. Of the 1,4-lactones examined, only the trimethylsilyl ether of D-mannono-1,4-lactone was obtained in crystalline form. However, all of the derivatives showed characteristic differences in their infrared spectra in the range of 1500 to 600 cm"1. When this method was applied to the determination of uronic acids in a variety of polysaccharides,205 it was impossible to find any hydrolytic conditions under which the uronic acids were quantitatively released and then reduced, a problem experienced by other workers.20 The method was, however, successful in affording a qualitative, microscale procedure for the identification of hexuronic acids (which otherwise are difficult to detect). 

The anomeric, methyl /3-D-glycoside lactone has also been synthesized by methylation of methyl /3-D-glucofuranosidurono-6,3-lactone.24 Trimethyl glucurone, formed by methylation of D-glucuronolactone with methyl iodide and silver oxide, is usually accompanied by some 2,5-di-O-methyl-A D-glucaro-b,3-lactone methyl ester ( trimethyl glucuralone ), an oxidation product. 

Finally, Hirst s later contributions to monosaccharide chemistry must not be overlooked. With E. G. V. and Elizabeth Percival, four different trimethyl, 3,4- and 4,5-dimethyl, and the 4-methyl ethers of D-fructose were synthesized from isopropylidene derivatives having well established structures. Certain methyl ethers of D-mannuronic acid and D-glucuronic acid were also prepared, and their periodate oxidation was compared with that of related ethers of D-galacturonic acid. With Elizabeth Percival, he also contributed articles on the methyl ethers of mono- and di-saccharides, and on glycofuranosides from cyclic carbonates, to Methods in Carbohydrate Chemistry, Vol. 2 (1963). 

Somani, S.M. and Anderson, J.H., In vitro glucuronization of 3-hydroxy-phenyl-trimethyl ammonium by rat liver microsomes, Drug Metabol. Dispos., 5, 15, 1977. 

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