title: N-Alkylations of chitosan promoted with sodium hydrogen carbonate under aqueous conditions.
abstract: Chitosan was reacted with four alkyl halides, monobromoacetic acid, benzyl bromide, 2-bromoethanol, and monochloroacetic acid, in the presence of NaHCO(3) in water. Chemical structures, degrees of substitution, and degrees of polymerization of reaction products were studied by FT-IR, NMR, SEC-MALLS, and elementary analyses. All alkyl groups were introduced selectively into the C2-amine groups of chitosan, and the yields of the N-alkyl chitosans were >90% by this method. N-Carboxymethyl chitosan (N-CMCh) and N-benzyl chitosan (N-BnCh) with high degrees of substitution (DS) up to 200% and 164% of the C2-amine groups, respectively, were obtained; N,N-dicarboxymethyl and N,N-dibenzyl chitosans were obtained in high yields. Degrees of polymerization (DP) of N-CMCh decreased during the reaction. The greater the amount of monobromoacetic acid added, the lower the DP of N-CMCh.
authors.affiliation: Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kurita
authors.forename: A
authors.initials: A
authors.lastname: Isogai
mesh_terms: D000478:Alkylation; D048271:Chitosan / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry; D008970:Molecular Weight; D009584:Nitrogen / Q000737:chemistry*; D017693:Sodium Bicarbonate / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D006219:Halogens; D014867:Water; D017693:Sodium Bicarbonate; D048271:Chitosan; D009584:Nitrogen