Dialdehydes carbohydrates

Most of the compounds in this group are dialdoses or their derivatives, and are derived formally from aldoses by oxidation of the terminal —CH2OH group to —CHO. Other representatives of the group are streptose and some other branched dialdehyde carbohydrates. 

Many types of mono-, bi-, and multifunctional coupling reagents are available for labeling antibodies or antigens with an enzyme. Glutaraldehyde, carbodiimide, N-succinimidyl-3-(2-pyridyldithio)propionate, and periodate oxidation of carbohydrate moieties to form active dialdehydes are several commonly used approaches in the preparation of enzyme conjugates (104-106). 

The periodate oxidation of carbohydrates, an important analytical technique, has been reviewed earlier in this Series.73 The dialdehydes obtained on periodate oxidation of polysaccharides have also been discussed.74 The requisite for the degradations to be discussed here is that part of the sugar residues in a polysaccharide are not oxidized by periodate and can be obtained separated from the oxidized residues as mono-, oligo-, or poly-saccharide derivatives after some chemical treatment. Characterization of these products may then give significant structural information. 

One of the most important reagents in investigations of carbohydrate structure is periodic acid (or sodium periodate).255 This reagent oxidatively cleaves C-C bonds bearing adjacent OH or NH2 groups to form dialdehydes (Eq. 4-12). The method is quantitative. After some hours of reaction, excess periodate not consumed in the oxidation can be determined. 

Guthrie, R. D., The Dialdehydes from the Periodate Oxidation of Carbohydrates, 16, 105-158... 

Malonaldehyde, a three-carbon dialdehyde (OHC- -CHO), is produced during lipid peroxidation by the oxidative decomposition of arachi donic and other unsaturated fatty acids. Malonaldehyde is present in a number of food products and its concentration is increased by irradiation of cellular amino acids, carbohydrates, deoxyribose, and DNA. Recent surveys (31-32) have confirmed the presence of malonaldehyde in supermarket samples of meat, poultry, and fish,... 

Mehltretter, C. L. (1964). Dialdehyde starch. Methods in Carbohydrate Chemistry, Vol. IV, p. 316. Academic Press, New York. 

Catalytic aldol reactions are among the most useful synthetic methods for highly stereo-controlled asymmetric synthesis. In this account we discuss the recent development of a novel synthetic technique which uses tandem enzyme catalysis for the bi-directional chain elongation of simple dialdehydes and related multi-step procedures. The scope and the limitations of multiple one-pot enzymatic C-C bond formations is evaluated for the synthesis of unique and structurally complex carbohydrate-related compounds that may be regarded as metabolically stable mimetics of oligosaccharides and that are thus of interest because of their potential bioactivity. 

This review will be limited to a discussion of the structures and reactions of the aldehydes obtained from oxidation of cyclic carbohydrate derivatives. Such products as that from the oxidation of 1,2-0-isopropylidene-D-glucofuranose, which is a monoaldehyde, will not be dealt with. A monosaccharide derivative will normally give rise to a dialdehyde, a disaccharide derivative to two dialdehyde units linked together (or a tetra-aldehyde), and a polysaccharide will give a dialdehyde polymer (a polyaldehyde). All of these classes of compounds will be discussed. 

The uses of periodate-oxidized carbohydrates are thus far confined to uses for oxycelluloses and, more particularly, oxystarches ( dialdehyde starches ). Following the development of the electrolytic regenerative process for periodic acid, oxystarch has been produced commercially in the United States by the Miles Chemical Company of Elkhart, Indiana. 

Secondly, selective chemical modification may be performed because the carbohydrate residues have a distinct low reactivity. This can be done by periodate oxidation which cleaves C-C bonds bearing adjacent hydroxyl groups and converts them to aldehydes [25,26]. The generated dialdehyde can react with a variety of nucleophiles - usually primary amino groups on the surface of carrier materials. The resulting Schiff bases can be further stabilized by sodium boro-hydride, sodium cyanoborohydride or pyridine-borane reduction [27]. 

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