Glyoxal periodate oxidation

Head showed that, whereas periodate-oxidized methyl jS-cellobioside (121) is quite labile to alkali and gives glyoxal, periodate-oxidized methyl jS-D-glucoside (122) reacts only slowly with alkali to produce acidic products,... 

The reaction of these aldehydes, derived from periodate oxidation, with carbonyl reagents has also been investigated. Studies 147 148 were made on oxidized laminarin, a (1 —> 3)-linked polysaccharide, in which only the terminal residues had been oxidized. The addition of phenylhydrazine acetate detached the remainder of the terminal residue as glyoxal phenyl-osazone. When the aldehydic compounds derived from the periodate oxidation of raffinose and trehalose818a were reacted with p-nitrophenylhydrazine, the authors were surprised to find that one molecule of oxidized raffinose, containing six aldehydic functions, reacts with only three molecules of the reagent, and that the four aldehydic functions of the oxidized trehalose molecule react with only two. The reactions of periodate-oxidized carbo-... 

However, Head showed that glyoxal is produced by the treatment of both oxycellulose and periodate-oxidized methyl fl-cellobioside (121) with alkali. The other theory was that of Haskins and Hogshead, based on the p-alkoxycarbonyl elimination mechanism of Isbell for the formation of saccharinic acids on treatment of sugars with alkali. They suggested that fission of the C5—O bond would yield glyoxal and n-erythrose. Recent work has indicated that the degradation is, indeed, based on a jS-alkoxycarbonyl elimination, but the products are different from those postulated above. 

Xylose 1-phosphate was obtained from UDP-xylose-/ by treatment w ith phosphodiesterase and was subjected to periodate oxidation, followed by bromine oxidation and acid hydrolysis to yield glyoxalic acid from carbon atoms 1 and 2 and glycolic acid from carbon-4 and 5. In these two products the nonexchangeable, carbon-bound hydrogen atoms originally present in positions 1 and 5 still remain, whereas the hydrogen in positions 2 and 4 has been removed. The products were nonradioactive, indicatir that the xylose formed from UDP-glucuronio acid-4f does not contain label at either carbon-1 or 5. 

Oxidation of the trioxane ( paraldehyde ) to glyoxal by action of nitric acid is subject to an induction period, and the reaction may become violent if addition of the trioxane is too fast. Presence of nitrous acid eliminates the induction period. 

These results may be explained on the basis that xylan possesses a linear chain of 1,4-linked anhydroxylose units. However, it should be pointed out that on hydrolysis of the oxidized xylan, some D-xylose is found in addition to the expected glyceraldehyde and glyoxal.I04(b) While it is possible that the oxidation reaction is not complete, another explanation is that a branched xylan chain may be present. If branching occurs on a pentose chain unit, only one free hydroxyl would remain on the unit hence, it would not be oxidized or degraded during the course of the periodate reaction. 

Periodic acid oxidation will also act on a-hydroxy aldehydes and ketones, a-diketones, a-keto aldehydes, and glyoxal. If the two neighboring hydroxyl groups are on an aromatic ring, the carbon-carbon bond is not cleave but the reactant is still oxidized. Thus, catechol is oxidized to the corresponding quinone. 

Several mechanisms34 have been proposed for this reaction. That of Weygand,36 in which an Amadori rearrangement is proposed, has considerable merit.37 Illustrations of unusual osazone formation are described by Bonner and Drisko.38 When phenyl /S-D-xylopyranosyl sulfone (XXII) or /J-D-glucopyranosyl sulfone (XXIV) is oxidized by periodic acid, a dialdehyde oxidation product (XXIII or XXV), which is susceptible toward further oxidation, is obtained. The reaction of XXIII or XXV with phenylhydrazine yields glyoxal phenylosazone and benzenesulfinic acid. Surprisingly, both XXII and XXIII react with phenylhydrazine to form D-xylosazone and D-glucosazone, respectively. 

In connection with preliminary structural work on the hexitols, an unexpected result arose during attempted identification, by conversion into a (p-nitrophenyl)hydrazone, of the dialdehydes (8) or (9), formed by periodic acid oxidation of tbe anhydrodeoxyhexitols (6) and (7), or (21) and (22). The dialdehydes (8) were cleaved to form glyoxal and a 2-deoxytetrose [isolated as the (p-nitrophenyl)hydra-zone ]. 

Oxidation — Apart from C02 and H20, there are three series of products that result from the oxidation of saccharide. They are 2,3-dialdehydes (5.43 and 5.49) formed on the oxidative cleavage of saccharides (5.42 and 5.48) with periodates, the sole oxidants providing such course of oxidation. Such dialdehydes are considered toxic. Further oxidation of dialdehydes leads to glyceric acid (5.45), glyoxalic acid (5.47), hydroxypyruvic acid (5.46), and erythronic acid (5.51), as shown below for the oxidative cleavage of sucrose (5.42) and maltose (5.48). 

In references dealing with the above mentioned procedure, using periodate as an oxidant and not using bromate, it is stated that formaldehyde, acetic aldehyde, glycolic acid, oxalic acid, formic acid, amlone dialdehyde, and glyoxal do not interfere. 

Tartaric acid was oxidized with sodium periodate to generate glyoxalic acid in situ, and the reaction mixture was added to a suspension... 

In a continuation of his studies on asymmetric P-lactam synthesis, Evans [42] utilized a,P-epoxyaldehydes 49a and 49b, prepared in two steps from achiral allylic alcohols via Sharpless asymmetric epoxidation and Swern oxidation, as chiral glyoxal synthons for the ketene-imine cycloaddition. Diastereosel-ection was excellent, ranging from 90 10 to 97 3 with overall yield of 50 up to 84% (for Schiff base formation and cycloaddition) after recrystallization or chromatographic purification of the major diastereomer. The sense of asymmetric induction correlated with that obtained in the analogous glyceraldehyde reaction, as established by periodic acid cleavage to aldehydes 51. 

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