Mannaric acid preparation

Proof of the structure of the uronic acid was obtained by Hirst, Jones and Jones,46 who isolated the methyl glycoside methyl ester by methyla-tion of the products from the graded methanolysis of alginic acid. The tri-O-methyl-D-mannuronic acid was converted to the diamide of 2,3,4-tri-O-methyl-D-mannaric acid, which had previously been prepared from... 

Tetra-O-methyl-D-mannaric and galactaric acids and their bis(pentachlorophenyl) esters have been prepared [99] as crystalline compounds, in good yields, from D-mannitol and galactitol, respectively. A new stereoregular fully sugar-based polyamide, analogous to Nylon 66, has also been prepared [99] by polycondensation of bis(pentachlorophenyl) 2,3,4,5-tetra-O-methyl-D-mannarate with l,6-diamino-l,6-dideoxy-2,3,4,5-tetra-<9-methyl-D-mannitol dihydrochloride [100]. 

In contrast to galactaric acid, D-mannaric and D-glucaric acids are appreciably soluble in water. Glucaric acid is best prepared by the nitric acid oxidation of starch yields as high as 65% are obtained in contrast to much lower yields from glucose or sucrose 50), This acid is generally characterized as the potassium acid salt or silver salt. 

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