Formazan reaction

The editors note with regret the passing of Laszld Mester on February 23, 1986. Mester worked extensively on hydrazine derivatives of sugars, and he contributed a notable article on the formazan reaction in Volume 13 of this series. 

Mester, L., The Formazan Reaction in Carbohydrate Research, XIII, 105-167... 

Reaction of the dialdehyde with phenylhydrazine gave a derivative which formed an amorphous diphenylformazan (which, further, gave a monoacetate). Structure (55) was proposed for the formazan. Reaction of the dialdehyde with (p-nitrophenyl) hydrazine gave an amorphous mono-hydrazone, which was hydrolyzed by acid to glyoxal bis[(p-nitrophenyl)-hydrazone) and glycerose (as pyruvaldehyde). Structure (56) was assigned... 

Various experiments made in this institute in recent years ( S, 10-lS) showed that the formazan reaction lent itself readily to studies of the structure of oxidized sugar derivatives whenever free aldehyde groups were present. Obviously, it was a useful reaction for investigations into the structure of ozone-oxidized carbohydrates, among them the sugar alcohols that had been studied by Harries. 

The present work showed, in perfect agreement with Harries, that on ozonizing sugar alcohols in an aqueous solution, they begin to oxidize and aldoses arise in the course of the oxidation process. For instance, n-mannose was prepared from ozone-oxidized D-mannitol with the aid of the formazan reaction, n-mannose was then identified as D-manno-V,V -diphenyl formazan (8). 

Other sugar alcohols, such as n-sorbitol and n-dulcitol, give an aldose phenylhydra-zone which is hard to isolate and convert to the formazan. Therefore, the aldose (n-glucose from n-sorbitol) was transformed into glucosazone, which was identified with the aid of the formazan reaction as n-glucosazone formazan (4). 

VIII. The Formazan Reaction of Periodate-oxidized Sugar Derivatives. 148... 

XI. The Formazan Reaction as a Means for Establishing the Structure of Polysaccharides. 162... 

The reaction mechanism of formazan formation has been studied by many researchers. The fundamental work of Busch and his coworkers and the studies by Hiinig and Boes, and by Hauptmann and Perissd, merit special mention. A host of other authors have endeavored to widen the sphere of application of the formazan reaction, and have extended it successfully to the 4,4-iV-diarylsemicarbazonesi and guanylhydrazones, -i respectively. 

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