Synthesis and characterization of nucleophilic polysaccharide carbazates

A simple synthesis of amino polysaccharides (PS) could be developed. Phenyl carbonates (PC) of xylan, dextran, and cellulose were easily transferred into PS carbazates by conversion with hydrazine hydrate. The degree of substitution could be adjusted by varying the molar ratio of hydrazine to PS repeating unit, enabling the preparation of both pure PS carbazates and derivatives with bifunctional reactivity containing the reactive PC and the amino group of the carbazate moiety. Further functionalization of the derivatives is feasible with carbonyl compounds like aldehydes at the carbazate groups. The reactivity of carbazate groups is shown by the reaction with 4-fluorobenzaldehyde, resulting in the formation of Schiff base conjugates.