Protecting group free synthesis of urea-linked glycoconjugates: efficient synthesis of ß-urea glycosides in aqueous solution.

A method for the protecting group free synthesis of ß-urea-linked glycoconjugates has been developed. The one step process, involving reactions between urea and D-glucose, N-acetyl-D-glucosamine or D-xylose in acidic aqueous solution, furnishes the corresponding ß-urea glycosides in modest yields. This simple and efficient procedure is applicable to the synthesis of ß-urea tethered amino acid-carbohydrate conjugates.