Mucic acid

Vigorous oxidation of a monosaccharide (e.g., with dilute 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 

Glucose Saccharic acid Galactose Mucic acid 

The approximate times of osazone formation in minutes are given in Table 111,139. The product from mannose is the simple hydrazone and is practically white. Arabinose osazone separates first as an oil, wliilst that from galactose is highly crystalline. Lactose and maltose give no precipitate from hot solution. 

Acetates. Complete acetylation of all the hydroxyl groups is desirable in order to avoid mixtures. In some cases, the completely acetylated sugars may be obtained in the a- and pforms depending upon the catalyst, e.g., zinc chloride or sodium acetate, that is employed in the acetylation. The experimental details for acetylation may be easily adapted from those already given for a- and p-glucose penta-acetates (Section 111,137). 

p-Nitrophenylhydrazones. This reagent has been used in the characterisation of a number of monosaccharides. 

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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. 

Dissolve 10 g. of lactose (1) in 100 ml. of nitric acid, sp. gr. 115, in an evaporating dish and evaporate in a fume cupboard until the volume has been reduced to about 20 ml. The mixture becomes thick and pasty owing to the separation of mucic acid. When cold, dilute with 30 ml. of water, filter at the pump and set the filtrate A) aside. Wash the crude acid with cold water. Purify the mucic acid by dissolving it in the minimum volume of dilute sodium hydroxide solution and reprecipitating with dilute hydrochloric acid do not allow the temperature to rise above 25°. Dry the purified acid (about 5 g.) and determine the m.p. Mucic acid melts with decomposition at 212-213°. 

Lactose (hydrated). Lactose (anhydrous) 2031 223 + 52-5 200 — Octa-acetate, a- 152, P- 90 mucic acid, 213... 

Pyrolysis of the methylamine salt (produced by neutralising mucic acid with aqueous methylamlne) in the presence of glycerol yields JV-methylpyrrole ... 

Oxidation of galactose (or a galactose-containing sugar) to mucic acid. Dissolve 1 g. of galactose or lactose in a mixture of 10 ml. of water and 5 ml. of concentrated nitric acid contained in a small evaporating dish, and evaporate the solution to dryness on a water bath. Stir the cold residue with 10 ml. of cold water, filter off the mucic acid, wash it with cold water, dry and determine the m.p. (212-213° with decomposition). 

Mucic acid [526-99-8] Mucoadhesives Muconic acid [505-70-4] Mucopolysaccharidoses Mucor circinelloides Mucor spp. 

Furancarboxylic acid may be prepared by the dry distillation of mucic acid, by the oxidation of furfural with potassium... 

MUchzucker, m. milk sugar, lactose, -agar, m. lactose agar, -saure, /. saccholactic acid (mucic acid). 

Pyro-phosphorsaure, /. pyrophosphoric acid, -saure, /. pyro acid, -schleimsaure, /. pjto-mucic acid, furoic acid, -schwefelsaure, /. pyrosulfuric acid, disulfuric acid (H2S2O7). 

Schleim-saure /. mucic acid, -schicht /. layer of sHme or mucilage or mucus specif., mucous layer, Malpighian layer (of the epidermis). -stoff m. sHmy substance mucin. 

Mucic Acid (Galactaric acid, Galactosaccharic acid, Tetrahydroxyadipic acid, Saccharolactic acid.Schleimsaure (Ger). 

The Synthesis of Some Galactaric (Mucic) Acid Derivatives, K. Butler, D. R. Lawrence, and M. Stacey,/. Chem. Soc., (1958) 740-743. 

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

The mucic acid test is now only of historical interest. It depends on the oxidation of galactose or saccharides containing a galactose residue, such as lactose, with nitric acid to yield mucic acid. Mucic acid is highly insoluble in water, while the isomeric dicarboxylic acids yielded by other sugars are soluble. Mucic acid may be identified by its characteristic thallium salt. 

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