Synthesis of Glycosylamines for Conjugating Glycans

The following protocol for synthesis of glycosylamines from reducing sugars is based on the method of Likhosherstov et al. (1986). 

Prepare a solution of the saccharide to be aminated at a concentration of up to 1 percent (w/v) in an aqueous solution of saturated ammonium carbonate. Even higher concentrations of saccharides may be used if the carbohydrate being modified is abundant and inexpensive. 

React with stirring at room temperature for up to 5 days. Over the course of the reaction, add to the solution solid ammonium carbonate at a rate of about 40 mg per mg of saccharide to assure continued saturation. 

After the reaction, freeze the solution and lyophilize to remove excess ammonium carbonate. Complete removal of volatile salt can be accomplished by re-dissolving the solid in warm methanol. After the completion of CO2 evolution, dry the saccharide by evaporation under vacuum. Removal of ammonium carbonate is essential, as the ammonium ion will interfere with any subsequent conjugations attempted with the glycosylamine derivative. 

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