Oxidation of maltose

The rate of oxidation of ethylene glycol was found268-269 to attain a broad maximum between pH 2.5 and 6. In a very complete study of the effect of pH on the periodate oxidation of carbohydrates, Neumiiller and Vasseur260 showed that the oxidation of maltose, melibiose, methyl a-D-... 

Lewis201 postulated maltosone as the first product in the oxidation of maltose by Fehling solution, but no osone was detected when maltose was treated with Fenton s reagent.23 Oxidation of maltosone with bromine water gave 2-oxo-maltobionic acid, isolated as its brucine salt.191... 

Microbial oxidation of maltose by Agrobacterium tumefaciens to give 4-0-(a -D-rtbo-hexosyl-3-ulose)-D-glucose (62) has been reported.147 Chemical oxidation of methyl, 2,6,2, 3, 4, 6 -hexa-0-acetyl-... 

Bromine oxidation of maltose followed by methylation and hydrolysis gives 2,3,4,6-tetra-O-methyl-D-glucopyranose and a tetramethyl-D-gluconic acid, which readily forms a -y-lactone. 

Glattfeld and Hanke applied this procedure to the oxidation of maltose hydrate. An aqueous solution of the sugar was shaken with lead carbonate and bromine since lead bromide separated from the reaction mixture, only aeration was necessary to remove the excess bromine, and treatment with silver oxide and hydrogen sulfide removed the last bromide, silver and lead ions. The maltobionic acid was isolated as the calcium salt. Here the neutralization of the hydrobromic acid was beneficial in preventing any hydrolysis of the aldobionic acid. 

The saccharinic acids formed from some of the pentoses and hexoses have been the objects of study by Nef and his students. Glattfeld and Hanke reported in 1918 that, during the oxidation of maltose in alkaline solution, an acid had been produced whose phenylhydrazide had an analysis agreeing perfectly with that calculated for a four-carbon saccharinic acid. Furthermore, the properties of the free aeid were those which would be expected of one of these acids. Its configuration could not, however, be reported at that time because of the absence of data as to the properties and constants of the four-carbon saccharinic acids. Nef had also referred to the handicap which this lack of information had imposed on the work with sugars in alkaline solution. Consequently, with this in mind, Glattfeld began in 1920 the systematic synthesis of the four-carbon saccharinic acids. 

The first encounter that the young Wolfrom had with the chemistry of carbohydrates came at the end of his sophomore year, when Professor C. W. Foulk recommended him for a post of student research assistant to Professor William Lloyd Evans of the Department of Chemistry. The stipend was 250 per year, and Wolfrom put in all of the extra time that he had on the work. During his junior year, he carried out quantitative oxidations of maltose with permanganate at various temperatures and concentrations of alkali. In his senior year, he attempted unsuccessfully to synthesize amino acid esters of glycerol. None of this work was published, but it was a good introduction to chemical research. Professor Evans, a student of J. U. Nef s, was very research-minded and inspirational. 

FIGURE 22.10 (a) Oxidation of maltose to maltonic acid followed by metfiylation and hydrolysis. 

Reports have been published on the kinetics and mechanisms of the oxidations of maltose, lactose, glucono-1,5-lactone 6-phosphate and glucodialdehyde 1-phosphate by Ce(IV), of D-galactose and several other monosaccharides by V(V), all in dilute... 

In the oxidation of maltose by cupric ions in ammoniacal solution in which the tetra-ammine copper(Il) ion is formed, the rate was found to be independent of the concentration of copper(ll) ion, to be proportional to that of maltose and to have a dependence on the square root of the concentration of ammonia. A common ion effect was observed by retardation of rate on addition of ammonium chloride. 

One notices that the data from the oxidation of melezitose by per-iodic acid confirm the pyranose structure of the D-glucose unit in turanose, and therefore also in the case of maltose, in agreement with the original assignments for both of these disaccharides from methylation studies. 

A liquid membrane bioreactor was developed as a means of encapsulation for a multi-enzyme system incorporating an oxidation and carbohydrate cleavage, demonstrated using a-glucosidase and glucose oxidase in the conversion of maltose to gluconic acid ... 

Oxidative, degradative reactions of maltose have been studied,136-138 and reviewed in this Series,139-142 and this subject will not, therefore, be discussed. The selective oxidation of primary52,143-146 and secondary66,147 hydroxyl groups in maltose has been investigated. The synthesis143 of maltouronic acid, 4-0-(a-D-glucopyranosyluronic... 

Stodola, F. H. and Lockwood, L. B. 1947. The oxidation of lactose and maltose to bionic acids by pseudomonas. J. BioL Chem. 171, 213-221. 

Some microorganisms effect the oxidation of oligosaccharides to glycosid-3-uloses this conversion has been reported for maltose, lactose, and their respective aldobionic acids. Conditions for the oxidation of sucrose by the action of Agrobacterium tumefaciens have been improved and optimized on a molar scale, so that 3-ketosucrose can be produced in 40% yield 449... 

In perchloric acid, hexoses and pentoses are oxidized by Ce(IV) via formation of two complex intermediates. The first is partly oxidized following Michaelis-Menten kinetics and partly dissociated to the second, which is oxidized more slowly than the former.180 The first step in the oxidation of aldoses by Tl(III) in the same medium involves the C-l-C-2 cleavage of the aldehydo form of the sugar. Thus, D-glucose gives D-arabinose and formic acid. With an excess of oxidant the final product is carbon dioxide.181 In the presence of a catalytic amount of sulfuric acid in acetic acid, Tl(III) oxidizes maltose and lactose to the corresponding disaccharide aldonic acids. The reaction showed activation enthalpies and enthropies characteristic of second-order reactions.182... 

In ammoniacal solutions of copper salts, the oxidation products are likely to contain nitrogen thus, hexoses give oxalic acid, imidazoles, hydrogen cyanide, and urea. Kinetic studies have been reported for the reaction of Cu(II) in the presence of ammonia with maltose, lactose, melibiose, and cellobiose.190 For the oxidation by tetraamminecopper(II) in ammoniacal and buffered media the rate of reaction is first order in disaccharide concentration, order one-half in ammonia concentration, but it is independent of Cu(II) concentration. The reaction rate is decreased by the addition of ammonium chloride, because of the common ion effect. These kinetics suggested mechanisms involving an intermediate enediolate ion, with the rate of reaction being equal to the rate of enolization.191 A similar mechanism has been proposed for the oxidation of D-fructose by a copper-pyridine complex in an excess of pyridine.192... 

Improved stability towards oxidation of spray dried flavor oils was achieved by using a combination of a high-maltose syrup, maltodextrin and a high molecular weight, film-forming polysaccharide, such as starch octenylsuccinate or gum ara-bic.200 201 Emulsification performance of maltodextrins is improved by treatment with octenylsuccinic anhydride and aluminum sulfate. 

Oxidation of lactose and maltose with Au/Ti02 catalysts has been reported to give close to 100% selectivity to lactobionic acid and malto-bionic acid, respectively63 which have potential uses in the pharmaceutical and detergent industries, as well as in food. Studies of the catalytic conversion of glucose by hydrogenation and oxidation to produce sorbitol and gluconic acid respectively have also been reported.64 Sorbitol is also manufactured on a 60 000 tonnes per annum scale. 

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