Phenyl-glucosazone—

Osazone formation. The preparation of glucosazone has already been given (p. 137). It may be carried out on a small scale by either of the following methods, according as (a) the phenyl hydrazine base, or (Z>) one of its salts, is used. 

Phenylhydrazinc, as hydrochloride solution plus sodium acetate, reacts with polyhydroxy aldehydes or ketones yielding osazones or diphenyl-hydrazones, yellow solids, of definite melting point and utilized in identification of sugars, e.g.. phenyl-d-glucosazone. CH OH (CHOH), C (NNHC6H5)CH (NNHCftH,) plus aniline C6H5NH plus NH,... 

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. 

Watters, Hockett and Hudson1 have prepared a non-crystalline monomethylmannose which forms an osazone with the same properties as those of 6-methyl-n-glucosazone. The synthesis was achieved by methylation of methyl 2,3,4-triacetyl-a-D-mannopyranoside, followed by hydrolysis. Schmidt and Heiss,13 studying the epimerization of 6-methyl-D-gluconic acid, have claimed to have isolated the phenyl-hydrazide of 6-methyl-n-mannonic acid. 

Osazones. Glucosazone.— This intermediate product, the oxidation compound, containing, now, a new carbonyl group, reacts with a third molecule of phenyl hydrazine forming a double phenyl hydrazone which is known as an osazone. From glucose the osazone is known as glucosazone. 

The structure of o-glucosazone formazan is also proved by the synthesis starting from D-glucosone l-(i T -phenyl)hydrazone. Coupling this with diazotized aniline in cold pyridine yields n-glucosone formazan [N,N - diphenyl - C - (d - arabino - tetrahydroxypentanoyl) formazan] as red needles. Condensation of this compound with phenylhydrazine leads to... 

Aronoff and Vernon (42) converted glucose to the glucosazone which was then degraded with periodate. This oxidation gave the bis(phenyl-... 

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