Osazones, anhydro

Cellobiose phenylosazone when treated by Diels method yielded a monoanhydride in the form of a hydrate. The same product was also obtained from cellobiose phenylosazone heptaacetate by deacetylation. The anhydride gave a pentaacetate proving that an oxide ring system was present, and structure XXXIII was proposed although the possibility of 1,3-anhydro- (1,5-oxide), 1,3-anhydro- (2,6-oxide) and 1,3-anhydro- (2,5-oxide) structures could not be rigidly excluded. 

Lactose phenylosazone heptaacetate yielded lactose phenylosazone anhydride hydrate,a compound previously isolated by Fischer and by Diels and Meyer. This compound also yields a pentaacetate the same structural possibilities occur here as in the case of the cellobiose phenylosazone anhydride mentioned above. 

Maltose phenylosazone heptaacetate, on the other hand, yielded two isomeric maltose phenylosazone anhydrides on deacetylation, both of which gave rise to pentaacetates like the other disaccharide anhydro-osazones, their precise structures are not known. It may be recalled that Diels and Meyer isolated a dianhydride of maltose phenylosazone 

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Diels and coworkers have shown that, when n-arafemo-hexulose phenyl-osazone is oxidized with oxygen (or air) in an alkaline medium, a dehydro-osazone is obtained which possesses two hydrogen atoms fewer than the parent osazone. On acetylation, the compound gives a triacetate, and its hydrazine residues could not be removed with p-nitrobenzaldehyde, suggesting their involvement in ring formation. The authors supported this view by the findings that dehydro-osazones cannot be obtained from methylphenylosazones or from the Diels anhydro-osazone (which, at that time, was believed to be a pyrazole compound). 

Hexosulose hydrazones and the mixed osazones react with diazotized aniline to give formazans, and with hydrogen peroxide to give pentonic acids. Unlike the mixed osazones obtained by transhydrazonation, the derivatives obtained from the glycosulose hydrazones are pure, uncontaminated compounds, and the positions of their hydrazone residues are well established. Thus, they afford remarkable possibilities, not only in the preparation of new types of compound, but also in enabling the reaction of osazones to be followed more closely, as in the case of triazole formation," and in studying the structure of anhydro-osazones. ... 

The reactions discussed in this Section are those involving the removal of the elements of water from osazones, and not merely the preparation of osazones from anhydro saccharides. There are, at present, three tjT>es of anhydro-osazone and, in all three types, the elements of water are eliminated from the hydroxyl group at C-3 and another group of the osazone, accompanied in some cases by inversion of configuration at C-3. 

Anhydro-osazones are also obtained when osazones are refluxed with acetic acid thus, di-0-acetyl-3,6-anhydro-n-n6o-hexulose 1-iV -acetyl-phenylosazone (92) is formed, together with the dianhydro-osazone (described on p. 178), from n-aroWwo-hexulose phenylosazone (43) and boiling acetic anhydride. On deacetylation, compound (92) yields Diels anhydro-osazone (90), and (92) can be prepared from the latter by acetylation with boUing acetic anhydride. 

L-a 2/lo-Hexose phenylosazone also gave the 3,6-anhydro-L-(2/a o-hexose derivative, and the phenylosazones from lactose and cellobiose yielded 3,6-anhydro-osazones, both with simultaneous Walden inversion on C-3. The D-galactose derivative, on the other hand, gave 3,6-anhydro-n-lyxo-hexose phenylosazone without inversion. 

Aus Triose-, Tetrose- und Pentose-osazonen entstehen in alkoholischer Losung 3-Alkoxy-osazone (vgl. S. 457), wahrend Hexose-osazone intra-molekular an intermediar gebildete Phenylhydrazono-en-phenyl-azo-Systeme zu 3.6-Anhydro-osazonen addieren ) (vgl. S. 458). 

Bildung von (bis jetzt nicht gefafiten) En-azo-phenylhydrazonen 106 - -118), die im Falle von Pentosen, Tetrosen und evtl. auch Triosen Alkohol zu 3-0-Alkyl-phenylosazonen addieren 118 - - 7/Pbzw. 120) und im Falle von Hexose-osazon eine intramolekulare Addition zu Anhydro-osazonen 121, 122) erfahren. 

Pazue, John H and Aronson, N. N., Jr., Glycoenzymes Enzymes of Glycoprotein Structure, 27, 301-341 Peat, Stanley, The Chemistry of Anhydro Sugars, 2, 37-77 Peat, Stanley. See also, Bourne, E. J. PERCIVAL, E. G. V., The Structure and Reactivity of the Hydrazone and Osazone Derivatives of the Sugars,... 

Osazone and (p-nitrophenyl)hydrazone formation without desul-fonylation has been accomplished in aqueous ethanolic acetic acid with 3,6-anhydro-5-0-p-tolylsulfonyl-D-glucofuranose. With 6-0-(me-thylsulfonyl)- and 6-O-p-tolylsulfonyl-D-galactose in methanol at room temperature for 2 days, the corresponding (2,4-dinitro-, (N-benzyl-, and (2,5-dichloro-phenyl)hydrazones were readily obtained. How-... 

Although Fischer described a lactose phenylosazone anhydride in 1887, little attention was paid to substances of this type until 1935 when Diels and Meyer reported the isolation of monoanhydrides of D-glucose phenylosazone, D-galactose phenylosazone, D-xylose phenylosazone, L-arabinose phenylosazone, lactose phenylosazone, and cellobiose phenylosazone, as well as a dianhydride of maltose phenylosazone, by boiling the corresponding osazones in alcoholic solution with a little sulfuric acid. Because of the apparent identity of the D-glucose phenylosazone anhydride with the 3,6-anhydro-D-glucose phenylosazone of Fischer and Zach, Diels and Meyer formulated these compounds as 3,6-anhydrides. 

D-glucose phenylosazone anhydride from 3,6-anhydro-n-glucose phenyl-osazone (XVI) in the following manner. In support of this view it is... 

In addition, it has been shown that Diels D-glucose phenylosazone anhydride is not identical with 3,6-anhydro-D-glucose phenylosazone for although the osazones are very similar, the diacetates have widely different properties. 

Page 77, lines 7, 8, and 9 from bottom. Between 3,6-Anhydro-n-allose phenyl-osazone and "2-methyl- insert the heading 3,6-Anhydro-n-altrose. ... 

Bayne observed that lactosazone is readily converted into anhydro-lactosazone in hot alcohol, and he recommended extraction with hot water for purification of the osazone. The water-insoluble anhydrolactosazone was identified as 3,6-anhydro-4-0-/3-D-galactopyranosyl-D-rf6o-hexose phenylosazone (39 R = D-galactopyranosyl) by conversion with aqueous copper sulfate to its phenylosotriazole, which was then hydrolyzed to give D-galactose and the phenylosotriazole of 3,6-anhydro-D-rf6o-hexose. 

Deacetylation with sodium methoxide, followed by reaction with phenyl-hydrazine, gave a mixture of three osazones, presumably n-Z /xo-hexose phenylosazone, 1,5-anhydro-D-er /[Pg.201]

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