Saccharate

By saccharic acid is usually meant D-gluco-saccharic acid, m.p. 125-126°C, obtained by the oxidation of glucose or starch. This exists in water solution in equilibrium with its two y lactones, both of which can be obtained crystalline, though the acid itself does not crystallize readily. 

Vigorous oxidation of a monosaccharide (e.g., with dUute nitric acid) produces carboxyl groups at both ends of the chain. Thus galactose gives the sparingly soluble mucic acid glucose affords the soluble saccharic acid, which is best isolated as the sparingly soluble acid potassium salt. 

COoH Saccharic acid 1 CHjOH Galactose 1 COjH Mucic acid... 

Disaccharides, e.g., lactose, which yield galactose upon hydrolysis, will also give the sparingly-soluble mucic acid but in poorer 3deld. This reaction may be employed for the differentiation between certain disaccharides lactose — mucic + saccharic acids sucrose — saccharic acid only maltose — saccharic acid only. 

Saccharic acid. Use the filtrate A) from the above oxidation of lactose or, alternatively, employ the product obtained by evaporating 10 g. of glucose with 100 ml. of nitric acid, sp. gr. 1 15, until a syrupy residue remains and then dissolving in 30 ml. of water. Exactly neutralise at the boiling point with a concentrated solution of potassium carbonate, acidify with acetic acid, and concentrate again to a thick syrup. Upon the addition of 50 per cent, acetic acid, acid potassium saccharate sepa rates out. Filter at the pump and recrystaUise from a small quantity of hot water to remove the attendant oxahc acid. It is necessary to isolate the saccharic acid as the acid potassium salt since the acid is very soluble in water. The purity may be confirmed by conversion into the silver salt (Section 111,103) and determination of the silver content by ignition. 

The reaction of aldoses with nitric acid leads to the formation of aldaric acids by oxidation of both the aldehyde and the terminal primary alcohol function to carboxylic acid groups Aldaric acids are also known as saccharic acids and are named by substi tutmg aric acid for the ose ending of the corresponding carbohydrate... 

Eisen-wasser, n. chalybeate water, -wein, m. Pharm.) iron wine, -weinstein, m. Pharm.) iron and potassium tartrate, tartrated iron, -werk, n. ironworks, iron mill, -wolfram, n. ferrotungsten. -zeit, /. iron age. -zement, m. n. ferroconcrete, -zinkblende, /. mar-matite. -zinkspat, m. ferruginous calamine, -zinnerz, n. ferriferous cassiterite. -zucker, m. Pharm.) saccharated ferric oxide, -zuk-kersinip, m. Pharm.) sirup of ferric oxide. 

Zucker-sdure, /, saccharic acid (Old Chem.) oxalic acid, -schaum, m. powdered w-nimol charcoal, -schlaxnm, m. (Beet Sttgar) lime... 

D-Saccharic acid 1,4-lactone (SAL 5-10 mM), a selective inhibitor of/3-glucuronidase [29], is often included in UGT reactions for improving yield. As /3-glucuronidases and UGTs have different optimal pH ranges, use of SAL in preparative-scale reactions may be avoided. 

Anhydro-D-manno-saccharic acid Isosaccharic acid 185 +46.18 H,0 51, 52, 4, 110... 

Anhydro-D-gluco-saccharic acid Epi-isosaccharic acid 160 +39.7 HjO 111, 55,110... 

Anhydro-D-allo-saccharic acid Chondrosic acid, Anhydrotalo-mucic acid 180 -16.6 HjO 111, 109,56... 

Anhydro-galacto-saccharic acid Epi-chondrosic acid, Anhydromucic acid 205 inactive HjO 111, 109... 

Two methylations of levan by means of dimethyl sulfate and potassium hydroxide (not sodium hydroxide) followed by one inethylation with methyl iodide and silver oxide yielded trimethyllevan in 88% yield. This was purified by solvent fractionation over-all yield 75%, m. p. 145-146°, OCHs 45.9%. Trimethyllevan, hydrolyzed by heating at 95° for twenty-four hours with a dilute solution of sulfuric acid gave a 98.5% yield of a crystalline trimethyl-D-fructose. The trimethyl-D-fructose was proved940 to be 1,3,4-trimethyl-D-fructofuranose since oxidation with nitric acid gave a 97% yield of a dimethyl-2-keto-D-gluco-saccharic acid which was identified as the crystalline diamide (95% yield). 

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