Osazones, anhydro derivs

The n.m.r. analyses of the osazones and anhydro-derivatives have been reported by El. Khadem and his co-workers. ... 

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,... 

No free 2-hydroxyglycals have yet been identified. 1,5-Anhydro-D-erythro-2,3-h.exodiuioaet bis(phenylhydrazone) (63, R = H, Ri = OH), which has been prepared from the product of deacetylation of 2-acetoxy-tri-0-acetyl-D-glucal, loses water when it is heated in aqueous acetic acid in presence of phenylhydrazine, giving a product believed to have the structure of 2,3-dihydro-6-(hydroxymethyl)-3,4-bis(phenylhydrazono)py-ran (64). This is, however, not identical with the osazone derived from... 

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. ... 

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. 

The sugar osazones are particularly prone to acid-catalyzed dehydration, and form monoanhydro derivatives when their alcoholic solutions are boiled with a trace of acid 69), (See also Chapter VIII.) With the hexose phenylosazones, there is produced a mixture of the epimeric 3,6-anhydro-hexose phenylosazones resulting from dehydration with and without... 

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