Amadori rearrangement

The Amadori rearrangement is an organic reaction describing the acid or base catalyzed isomerization or rearrangement reaction of the N-glycoside of an aldose or the glycosylamine to the corresponding 1-amino-1-deoxy-ketose. The Amadori rearrangement was discovered by the organic chemist Mario Amadori (1886–1941), who in 1925 reported this reaction while studying the Maillard reaction. The reaction is important in carbohydrate chemistry.

The reaction mechanism is demonstrated starting from the reaction of D-mannose in its closed (1) and open-form (2) with ammonia to produce the 1,1-amino-alcohol (3), which is unstable and loses water to the glycosylamine (again the open imine (5) and the closed form hemiaminal (4)), which is the starting point for the actual Amadori rearrangement.

By treatment of the glycosylamine with pyridine and acetic anhydride, the imine group rearranges and the intermediate enol, in turn, rearranges to the ketone. In this particular reaction, all the alcohol and amino groups are acylated as well.

The reaction is associated with the Maillard reaction in which the reagents are naturally occurring sugars and amino acids. A recent study has revealed the possibility of Amadori rearrangement during interaction between oxidized dextran and gelatine.

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