Saccharide Azines

The hydrazine derivatives of saccharide are here discussed in sections on saccharide azines, which are formed when one hydrazine molecule reacts with two saccharide molecules saccharide hydrazones and glycosylhy-drazines, which are the tautomeric acyclic and cyclic products formed when one hydrazine molecule reacts with one sugar residue saccharide osazones and poly(hydrazones), which are formed when two or more hydrazine molecules are linked to a saccharide residue and, finaly, hydrazones of carba-sugars and related compounds. 

Monosaccharides and reducing disaccharides react with unsubstiluted hydrazine to give azines, such as 2, which on prolonged treatment with an 

ScHliMH 1. Formation of azines, hydrazones, and azine hydrazones. 

It must, be emphasized that the term hydrazone is still used to designate products whose structures have not. been fully established. For example, many of the arylhydrazones that have been used in the isolation and 

Kinetic studies79 80 ha ve clarified the mechanism of formation of phenyl-hydra zones of aromatic aldehydes. It was found that, during the formation of bcnzaldehyde phenylhydrazonc 79 attack of the nucleophile is the ratedetermining step under slightly acidic conditions, whereas dehydration of the carbinolamine intermediate is the rate-determining step under neutral and basic conditions. 

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