Aldonic acids properties

The nitrile group is very sensitive to alkalis and the elimination of it by the action of potassium hydroxide on acetaldehyde cyanohydrin was described by Simpson and Gauthier as one of the reactions of the acetaldehyde cyanohydrin, a substance that they prepared for the first time. That the nitriles of the aldonic acids yield cyanides under the action of alkali, is described by Wohl as one of the properties of penta-acetyl-D-glucononitrile. 

Pfannemtiller et al. showed that it is possible to obtain carbohydrate-containing amphiphiles with various alkyl chains via amide bond formation. For this, mal-tooligosaccharides were oxidized to the corresponding aldonic acid lactones, which could subsequently be coupled to alkylamines [128-136]. Such sugar-based surfactants are important industrial products with applications in cosmetics, medical applications etc. [137-139]. The authors were also able to extend the attached mal-tooligosaccharides by enzymatic polymerization using potato phosphorylase, which resulted in products with very interesting solution properties [140, 141]. 

V. Table of Properties of 2,5-Anhydrides of Sugars, Alditols, and Aldonic Acids... 

Aldonic acids, characterization of, 373 —, 2-amino-2-deoxy-, deamination of, 191 —, 2,5-anhydro-, properties of, 220-229 Aldonolactones, 2-amino-2-deoxy-, deamination of, 189... 

All monosaccharides and their derivatives that possess aldehyde or ketone groups (that is, excepting derivatives such as alditols and aldonic acids) will have reducing properties. Moreover, those with the appropriate number of carbon atoms can form rings occurring in two forms (anomers) and in which the potential reducing carbon is called the anomeric carbon. 

The aldehyde group of aldoses can either be oxidized or reduced and ketoses can be reduced. The best laboratory reagent for reduction is sodium boro-hydride which acts rapidly in neutral aqueous solutions (see Eq. 4-2). Since both NaB H4 and NaB H4 are available, radioactive or heavy isotope labels can be introduced in this way. The aldehyde groups can be oxidized by a variety of agents to the corresponding aldonic acids, a fact that accounts for the reducing properties of these sugars. In alkaline solution aldoses reduce Cu + ions to cuprous oxide (Eq. 4-3), silver ions... 

Aldonic acids (e.g. melibionic and gentiobionic acids) derived from reducing disaccharides have been coupled to the amino-groups of proteins with the aid of a water-soluble carbodi-imide/ The immunochemical properties of some of the synthetic glycoproteins were assessed using plant agglutinins and antibodies raised towards the conjugates. 

Lactobionic acid (P-D-galactopyranosyl-(1 4)D-gluconic acid, LB A) is a relatively new product and an aldonic acid obtained from the oxidation of lactose, with high potential application as an ingredient in foods and pharmaceutical products, because of its antioxidant, chelating, and humectant properties (Gutierrez... 

We recall dilute nitric acid oxidizes aldoses to aldaric acids. The symmetry properties of the aldaric acid provide information about the possible configurations of the secondary hydroxyl groups. If the aldonic acid formed by oxidation is optically inactive, the hydroxyl groups occur in a symmetrical arrangement. For example, D-galactose gives an optically inactive aldaric acid... 

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