'Click chemistry' on polysaccharides: a convenient,general, and monitorable approach to develop (l->3)-beta-D-glucans with various functional appendages

摘要

(1->3)-beta-D-Glucans having various functional appendages (lactoside,ferrocene,pyrene,and porphyrin) can be prepared in an convenient,quantitative,and regioselective manner through regioselective bromination-azidation of curdlan to afford 6-azido-6-deoxycurdlan followed by chemoselective [3+2]-cycloadditions with various functional modules bearing a terminal alkyne group.The ability to monitor reaction conversions is an additional advantage of this synthetic approach over the conventional direct modifications on polysaccharides;the reaction can be readily monitored based on the intensity of azido peaks in the in situ attenuated total reflection infrared spectra.