Osones preparation

Substituted osones can be synthesized by the Grignard reaction. Di-0-isopropylidene-2-ketogluconic acid and phenyl magnesium bromide react to form l-C-phenyl-2,3,4,5-di-0-isopropylideneglucosone Some 1,1-C-diphenyl-2,3,4,5-di-0-isopropylidenefructose is also formed. Hydrolysis with boiling normal sulfuric acid in propanol forms the 1-C-phenylgluco-sone. This product is the first osone prepared in crystalline form. 

The condensation reactions of aromatic o-diamines and sugars and sugar derivatives have been studied in detail and quinoxaline derivatives have been prepared recently from osones, osonehydrazones, and dehydro-L-ascorbic acidd ... 

The nomenclature adopted in the designation of the analogs of L-ascorbic acid is based for convenience upon the name of the sugar from which the osone was prepared. For example, D-xylose (XVIII)... 

Partially methylated derivatives of D-glucosone have been prepared by decomposition of the corresponding partially methylated phenylosazones with p-nitrobenzaldehyde osones have been obtained from 5-0-methyl-D-glucose phenylosazone and from 3,4,5-tri-O-methyl-D-glucose phenylosazone in this way.22 Although 6-0-methyl-D-glucose phenylosazone is not altered by heating with benzaldehyde or piperonal in aqueous ethanolic... 

It has recently been reported21 that a mixed osazone of 3,4-di-O-methyl-D-glucose can be converted, by treatment with p-nitrobenzaldehyde, into an osone which reacts with phenylhydrazine to give 3,4-di-O-methyl-D-glucose phenylosazone. Von Lebedev29 claimed to have obtained D-glu-cosone 6-phosphate, isolated as an amorphous lead salt, by the action of hydrochloric acid on the phenylosazone prepared from D-fructose 6-phosphate. 

In the preparation of D-glucosone by the direct oxidation of D-glucose, D-fructose, or D-mannose by such reagents as that of Fenton,37 cupric acetate,16- 46- 46 selenious acid,16-61 etc., the degree of oxidation must be carefully controlled if the osone, which is the first product, is to be the main product of the reaction. The nature and mechanism of formation of the products of further oxidation of D-glucosone are discussed on p. 68. 

Neither of these reports has been confirmed, and, in both cases, evidence for the production of D-glucosone is incomplete, being based mainly on the preparation of non-definitive derivatives. These results are discussed more fully in the Section dealing with the biological significance of the osones. 

Berkeley96 investigated oxidase action in preparations obtained from the crystalline style of the mollusc, Saxidomus giganteus. He demonstrated the aerobic and anaerobic production of D-glucosone by separate systems, each of which comprised a component in the style and another in the diatomaceous food of the mollusc. The osone was identified through the formation of D-glucose m-nitrophenylosazone and by reduction with zinc... 

The tetrosones have not been prepared. Fischer2 observed that erythrose phenylosazone is relatively resistant to concentrated hydrochloric acid on warming, some decomposition took place, but osone was not formed. 

LaForge and Hudson194 prepared an osone from the phenylosazone obtained from sedoheptulose (D-aZ(ro-heptulose). The osone reduced Fehling solution strongly, formed the original osazone with phenylhydrazine, and gave a crystalline derivative with o-phenylenediamine. 

D-Glucoheptosone was prepared by treating D-glucoheptose phenylos-azone with concentrated hydrochloric acid.196 The osone was employed for the synthesis of D-glucoheptoascorbic acid. 

This osone was first prepared from cellobiose phenylosazone by the benzaldehyde method196 on hydrolysis by emulsin it gave D-glucosone and D-glucose. 

Lactosone was first prepared by the hydrochloric acid decomposition of the phenylosazone,1 although it had been noted that, in acid solutions, lactose phenylosazone forms an anhydride.197 Since its discovery,17 the benzaldehyde method has usually been employed,6-10-28 because it avoids the risks of osone hydrolysis and of alteration to the osazone. Lactosone is hydrolyzed by hot, dilute, mineral acid to D-glucosone and D-galactose.1-6 It reacts with cyanide to form an analog of iminoascorbic acid which, on acid treatment, is converted into a mixture of D-glucoascorbic acid and D-galactose.10... 

D-Galactosido-D-glucosone and D-glucosido-D-galactosone were prepared by Fischer and Armstrong203 by the action of benzaldehyde on the osazones of synthetic disaccharides. Both osones were hydrolyzed by emulsin. There is some doubt as to the precise structure of the parent sugars.206... 

These compounds are formally derived from aldoses by oxidation of a secondary hydroxyl group to a ketone group. The well-known aldos-2-uloses (usually termed simply aldosuloses or osones in former usage) have long been known in the form of their bis(hydrazone) derivatives, the osazones. Deoxyaldosuloses have been implicated as intermediates in a variety of degradation reactions. Aldos-3-, -4-, and -5-uloses have been prepared, principally as intermediates for synthesis. 

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