Homogeneous Sulfation of Xylan from Different Sources

Xylan sulfates have been prepared under homogeneous reaction conditions in DMF/LiCl applying SO3/pyridine and SO3/DMF. The degree of substitution (DSSulfate) of the products obtained was determined by elemental analysis. DSSulfate reached values of up to 1.90 applying a molar ratio of 3 mol sulfating agent per anhydroxylose unit. The structure of the xylans and of the xylan sulfates was studied in detail by one‐ and two‐dimensional NMR spectroscopy and MALDI‐TOF mass spectrometry. The sulfation of xylan was studied with the objective to obtain well‐characterized potentially bioactive xylan derivatives. Xylans from different plant sources were characterized prior to sulfation. The homogeneous derivatization of these xylans applying SO3‐complexes as sulfating agents was carried out in DMF/LiCl for the first time. It appeared that the DS value of the products can be controlled by varying the amount of the sulfating reagent in relation to the AXU. Structural differences between the xylan sulfates were confirmed by NMR spectroscopy and MALDI‐TOF mass spectrometry. The observed characteristics of xylan sulfates will support future investigations on structure–activity relationships.