N-Mannonic acid

Methyl 3,6-anhydro-a-D-manno-pyranoside 3,6-Anhydro-n-mannonic acid 131 + 97.1 HjO 14, 42... 

Watters, Hockett and Hudson1 have prepared a non-crystalline monomethylmannose which forms an osazone with the same properties as those of 6-methyl-n-glucosazone. The synthesis was achieved by methylation of methyl 2,3,4-triacetyl-a-D-mannopyranoside, followed by hydrolysis. Schmidt and Heiss,13 studying the epimerization of 6-methyl-D-gluconic acid, have claimed to have isolated the phenyl-hydrazide of 6-methyl-n-mannonic acid. 

These data indicate that the rate of hydrolysis of the lactones is also, to a considerable extent, affected by the stereoisomerism of the molecule. For instance, the lactones of n-mannonic acid are more stable than those of D-gluconic acid, from which they only differ in the steric position of the hydroxyl group at C2. A mixture of n-glucono-1,4-lactone and n-mannono-1,4-lactone can be fractionated by the absorption, on an anion-exchange... 

D-Gluconic acid, ammonium n-gluconate, sodium n-gluconate D-Arabonic acid, L-arabonic acid, potassium n-arabonate, citric acid D-Mannonic acid a-n-Galacturonic acid... 

Simple esters of the sugar acids, as ethyl D-mannonate 102) and diethyl galactarate 103), have long been known (Chapter VI). n-Galacturonic acid occurs in pectins largely esterified with methanol 104), Many of the methyl esters of the 0-acetyl aldonic acids have been obtained by the action of diazomethane upon the fully acetylated aldonic acids. Penta-0-acetyl-D-gluconates of some of the alditols (XVIII) and of cellulose have been described 106), The methyl acid ester of di-0-acetyl-L-(dea ro)-... 

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