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

Abstract

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. Experimental SectionMaterials. Chitosan, used as a starting material, was donated by Primex ehf (Reykjavik, Iceland). Weight-average molar mass (Mw) 148 200 Da and number-average molar mass (Mn) 94 200 were determined by GPC-LS. The degree of deacetylation (85%) was confirmed by 1 H NMR. All other chemicals used were commercially available and used as received. Pyridine was distilled over KOH. Dialysis membrane (M w cutoff 12 kDa) was purchased from Sigma (St. Louis, MO).Characterization. 1 H and 13 C spectra were recorded on a Bruker AVANCE DRX 500, operating at 500.13 and 125.76 MHz, respectively. Samples of chitosan N-betainates (40 mg) were dissolved in 600 µL of D 2O. Chemical shifts (δ) are

Synthesis and Evaluation of the Antimicrobial Activity of Dodecyl trimethyl ammonium and N-(N, N-dimethylamino) Propyl Glucosylamine

“…Typhimurium could be due to its remarked decomposition in D 2 O and research on its possible stabilization should be of interest. Through our findings, the reported antibacterial efficacy of ammonium compounds 21,24,28 was confirmed: satifying antimicrobial activity was obtained from small biodegradable molecule, dodecyl trimethyl ammonium sulphate. It is however to note that the toxicity assessment of this compound should be carefully realized before any application of this compound in various domains.…”

A Facile Route for Regioselective Conjugation of Organo‐Soluble Polymers onto Chitosan

“…The assignment of the peak at 2.85 ppm to the H-2 of the unsubstituted glucosamine residue in chitosan has been frequently reported previously. [15,[18][19][20][21] When stoichiometric SCC was used as an intermediate, the integration area ratios of A 1.85 /A 2.85 in all of the SCC-g-PEG were found to be almost the same as those in SCC. These results suggest that the amino groups remained intact and PEG was conjugated to SCC through hydroxyl groups.…”

Synthesis and characterization of the biodegradable polycaprolactone‐graft‐chitosan amphiphilic copolymers

“…Solubilization of the rigid polysaccharide is critical in order to obtain high degrees of substitution and to have control over the chitosan modification reactions. 10,11 The fact that chitosan is practically insoluble in most organic solvents makes the synthetic modifications of chitosan difficult. There have been some methods for preparing of polyester-graft-chitosan (chitin) copolymers.…”

“…Kurita and coworkers had developed 6-O-triphenylmethyl chitosan as an intermediate for chitosan modification, 16,17 and recently this intermediate has been proved to be effective in N-acylation. 11,18 In the present work, we report a method to synthesize welldefined PCL-g-Chi copolymers, i.e., by coupling activated hydroxyl groups on PCL chains with 6-Otriphenylmethyl chitosan (Tr-Chi) through amide bridge. Moreover, we have prepared nanoparticles with free amine groups on the surface from these novel graft copolymers in water, which may be used for targeting drug delivery.…”