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 reaction is important in carbohydrate chemistry.

The reaction mechanism is demonstrated starting from the reaction of D-mannose in its open (1) and closed-form (2) with ammonia 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 the all alcohol and amino groups are acylated as well.

The reaction is associated with the Maillard reaction with reagents naturally occurring sugars and amino acids.