Action of Bases on Osazones

Meyer and Onnen studied the effect of boiling alcoholic solutions of osazones with potassium hydroxide (1%). n-Glucose phenylosazone gave glyoxal phenylosazone and l,2-bis(phenylazo) ethylene, and in general, glyoxal phenylosazone was obtained in the other cases examined, except for cellobiose phenylosazone. Evidently fission takes 

Kenner and Knight point out that hydrazones are formed from free hydrazine bases, whereas hydrazine salts, such as phenylhydrazine acetate, yield osazones. It is emphasized that salt formation greatly favors such reactions as the production of amines from hydrazo compounds, a reaction which is represented as follows. The cation therefore 

An ingenious theory has been advanced by Weygand based on the observation that when aryl (p-tolyl-, p-phenetyl-) isoglycosamines (XL), produced from the corresponding nitrogen glycosides by the Amadori rearrangement, are heated with phenylhydrazine hydrochloride and 

Two possible routes are suggested for osazone formation under the usual conditions. The first involves formation of the phenylhydrazone, isomerization to an enolic form XLI followed by the loss of aniline to form an imino ketone XLII (or an imino aldehyde from a ketose) which is then converted to the osazone. Isbell depicts this reaction in terms 

The second alternative route suggested by Weygand is shown below. HjCNHNHCJEI, rHaCNHNHC.H.I 

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