Conjugated vinyl derivatives of chitooligosaccharide: Synthesis and characterization

The introduction of a conjugated vinyl group to chitooligosaccharide (COS) has been easily accomplished by the coupling of glycidyl methacrylate (GMA) to COS in aqueous solution without an additional catalyst. Depolymerizatio n of chitosan was carried out by deaminative cleavage using sodium nitrite. The average degree of polymerization of COS could be controlled by varying the molar ratio of sodium nitrite and the amino group of chitosan. The deg ree of substitution (percentage), as determined by H-1 NMR, of GMA to COS i ncreased up to 60% at a reaction time of 48 h. The structure of products (C OS-GMAs) were identified by Fourier transform infrared spectroscopy, H-1 NM R, and C-13 NMR. The resulting COS-GMAs were readily soluble in neutral wat er, like the original COS, and exhibited an excellent antimicrobial activit y. The reactivity of COS-GMA was investigated by the reaction with poly(vin yl alcohol) (PVA). The reaction products were found to have a lower crystal linity than WA because of the introduction of the COS-GMA units. (C) 2001 J ohn Wiley & Sons, Inc.