Synthesis and Characterization of Chitosan N-Betainates Having Various Degrees of Substitution

An efficient five-step synthetic route was developed for full N-substitution of chitosan with a quaternary betaine moiety. The developed synthetic procedure can also be controlled to produce chitosan N -betainates having lesser degrees of substitution. 6- O -Triphenylmethylchitosan, which is highly soluble in organic solvents, was used as an intermediate for N -acylation reactions. Intermediate products were characterized by 13 C CP/MAS NMR, FT-IR, and elemental analysis. The water-soluble quaternary chitosan N -betainates were thoroughly characterized by 1 H NMR and 13 C NMR and by 2D 1 H− 1 H COSY NMR and 13 H− 1 H HSQC NMR. Degrees of substitution were determined from the 1 H NMR spectra. A significant degradation of the polysaccharide backbone during the synthetic procedure was determined by GPC with a light scattering detector.