Galacturonic acid, methyl derivatives

Alduronic Acid Derivatives D-Galacturonic acid methyl 166.0 + 11.2 MeOH 246... 

In this clas of materials is grouped the majority of the seed mucilages, the acidity of which is due to a uronic acid (usually D-galacturonic acid) or to a methyl ether derivative of a uronic acid. This presence of D-galacturonic acid as the acidic component of the polysaccharide differentiates the mucilages from the gums, the acidity of the majority of which is due to the presence of D-glucuronic acid, or to one of its methyl ether derivatives (see above). 

Derivatives of 2-0-methyl-D-galacturonic acid were first synthesized by Jones and Stacey,30 who converted methyl (methyl a-D-galactopy-... 

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). 

The methylated galactoses obtained from tamarack galactan were analyzed as the per (trimethylsilyl) derivatives by Jiang and Timell, and the same derivatives were used by Larsson and Samuelson in a study of a galacturonic acid anhydride. 3-O-Methyl-n-galactose has been estimated in the hydrolyzate of a fungal heteropolysaccharide by using trimethylsilyl derivatives. ... 

A heat-labile endopolygalacturonase from culture filtrates of Rhizopus stolonifer elicited accumulation of the phytoalexin casbene in castor bean Ricinus communis). This material releases heat-stable water-soluble cell wall fragments from the host plant. These wall fragments contain a high fraction of galacturonic acid or its methyl ester, indicating their derivation from pectic polysaccharides (Ralton et al., 1987). 

Dissociation constants of o-glucuronic acid, o-galacturonic acid, their methyl ethers, and the corresponding 4,5-unsaturated derivatives have been measured and rationalized in terms of various operating electronic factors. Observations on details of the reduction of uronic acid esters to hexopyrano-sides, on nitrogen-containing derivatives, and on branched-chain uronic acids are made in Chapters 3, 9, and 13, respectively. 

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