Preparation of amphoteric N,O‐carboxymethyl hydroxypropyl chitosan by a two‐step reaction

Abstract

A novel N,O-carboxymethyl hydroxypropyl chitosan (HPCMS) derivative was prepared by a two-step reaction. Watersoluble hydroxypropyl chitosan (HPCS) with a degree of substitution of hydroxypropyl higher than 0.8 was first synthesized by the reaction of chitosan (CS) with propylene oxide (PO) with alkali as a catalyst. Then, amphoteric chitosan derivatives (HPCMS) with a degree of substitution of carboxymethyl ranging from 0.42 to 1.38 were prepared by the reaction of HPCS with chloroacetic acid in an aqueous solution with alkali as a catalyst. The structures of the polymers were characterized by Fourier transform infrared spectroscopy and NMR; this showed that the hydroxypropylation mainly occurred on the AOH groups at the C-6 of CS in the reaction of CS with PO. In the reaction of HPCS with chloroacetic acid, both the AOH and ANH 2 groups of HPCS were susceptible to the carboxymethylation.

Preparation and antibacterial activity of chitosan derivative membrane complexation with iodine

“…As shown, the signals between 4.7 and 5.2 ppm are the resonance of H1 and the signals between 3.2 and 4.1 ppm are the resonance of H2-H8. In addition the signals between 1.1 and 1.5 ppm are assigned to the resonance of the three protons from -CH 3 of HPCGH, 39 this indicates that a hydroxypropyl group had been introduced into the chain of CS. Moreover, the signals between 4.3 and 4.8 ppm are assigned to the resonance of the protons of C-NH-C and C-NH 2 , this indicates that a diguanidine group is graed to the CS.…”