Indicators, osazones

The unsaturated diamine, CgHgoNj, from the hydrolysis of sphero-physine, on oxidation with permanganate yields the ketoaldehyde, McgCH. CO. CHO fdioxime, m.p. 95-6°, and osazone, m.p. 113-4°) and putrescine, NH2[CH2]4NH2, which indicates that this unsaturated diamine is Me2CH. CH CH. NH[CH2]4. NH2. 

On interruption of the reaction at the minimum point, only a low yield of the final product, 5-(methoxymethyl)-2-furaldehyde, could be isolated as the semicarbazone, but a crystalline phenylosazone (m.p. 120.5-121.5°, [< ]d —9° in chloroform) was obtained. It was not isolable at the end of the reaction. No osazone was obtainable from the hydroxy-glycal without prior, acid treatment. Analyses of the osazone indicated that it was a mono-O-methyl derivative of the parent CgHgCh. This is the same formula that was found by Bergmann and Zervas (see above ) for the parent of the phenylosazone obtained by direct treatment of 2,3,4,6-tetra-0-acetyl-(2-hydroxy-D-glucal) with phenylhydrazine. Whereas Bergmann and Zervas were unable to acetylate the compound further, Wolfrom, Wallace and Metcalf introduced an O-acetyl group into their mono-O-... 

Although, as mentioned previously, other possibilities of isomerism exist, most attention has been devoted to attempts to decide whether sugar osazones are cyclic or acyclic. The results of methylation experiments indicate that under these conditions the osazones react as cyclic structures, but there is less certainty about the structure of acetylated osazones. 

To sum up, while the balance of the evidence indicates that the osazone acetates examined are probably acyclic, the possibility that cyclic acetates exist cannot at present be discarded. 

It will be observed that the hypothesis of intramolecular transformation advanced by us to explain the interconversion of glucose, fructose and mannose should be modified or rather extended. It would seem appropriate to postpone these theoretical considerations until the constitution of the new sugars has been established. It is to be noted, however, that the theory takes into consideration the existence of a great number of ketoses, it being possible for an intramolecular transformation of the kind indicated to take place among several carbons in the chain of the sugar. Fructose, for example, can produce in this way two new ketoses with a C==0 on carbon 3, which can be transformed, by reduction, into four different hexitols, and yet can form one and the same osazone. 

Problem 35.4 When (4 )-maltose is subjected to two successive one-carbon do-gradations, there is obtained a disaccharide that reduces Tollens and Fehling s reagents but does not form an osazone. What products would be expected from the acidic hydrolysis of this disaccharide What would these facts indicate about the structure of (+)-maItosc ... 

Sucrose likewise yields glucosazone identifiable as glucosazone formazan. This indicates that in sucrose it is the hydroxyl group on the first carbon atom of n-fructose which oxidizes to an aldehyde group. As has been observed by several authors (1, 7, 14), in the course of the formation of osazone the disaccharide bond 2, S) breaks up and glucosazone forms from both components of the disaccharide upon the addition of phenylhy drazine. 

It was found that the mutarotation of the sugar phenylosazones indicates a reaction of the first order, as shown in Fig. 14. With the solvent carefully evaporated in vacuo, the osazone is recovered unchanged. Repeated mutarotation takes practically the same course. As regards the ultraviolet spectra of the phenylosazones during mutarotation, a slight shift of the characteristic maximum at about 395 ma toward shorter wavelengths and a gradual disappearance of the minimum around 345 m/x are distinctly noticeable (see Fig. 15) the same holds true in respect to the recovered material. 

Fischer s formulation of phenylosazones in the acyclic structure, such as (43), was based on the fact that the same osazone is produced from two epimeric aldoses and the corresponding 2-ketose, as well as from their phenylhydrazones, indicating that, in the osazone, the phenyl-hydrazine residues are attached at C-1 and C-2 of the saccharide chain. As the asymmetry at C-2 is destroyed during the reaction, it is found that, for a given substituted hydrazine, there are eight isomeric hexose osazones (four D and four l isomers) and four pentose osazones (two d and two l). 

In 1944, Hann and Hudson found that, when refluxed with cupric sulfate, osazones are converted into colorless triazole derivatives which they designated osotriazoles. They determined the structure of the d-orahmo-hexulose derivative by means of the following reactions (1) it gave a tetraacetate and a tetrabenzoate which could be saponified to the parent osotriazole, indicating the presence of four free hydroxyl groups therein (2) on periodate oxidation, 3 moles of oxidant were consumed per mole of (71), giving 1 mole of formaldehyde, 2 moles of formic acid, and a known compound, 4-formyl-2-phenyl-l, 2,3-triazole (72). 

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