New selectively N-substituted quaternary ammonium chitosan derivatives

New chitosan derivatives were synthesized by N-selective introduction of qu aternary ammonium-type side chains without protection of hydroxy groups, al though direct quaternization of the amino group of chitosan using alkyl hal ides under alkaline conditions introduced alkyl groups not only to the amin o group but also to the hydroxy groups. The reductive N-alkylation reaction of chitosan with quaternary ammonium-type aldehydes, such us 4-formyl-N-me thylpyridinium iodide and [3-(4-formylphenoxy)propyl]trimethylammonium iodi de, followed by anion-exchange reaction gave partially N-p-(N-methylpyridin io)methylated chitosan chloride (N-MP [Cl-]) and partially N-4-[3-(trimethy l-ammonio)propoxy]benzylated chitosan chloride (N-TMPB [Cl-]), respectively . From the viewpoint of utilization as antistatic material for functional t extile, the electric resistance of newly prepared derivatives were investig ated. In comparison with known quaternary ammonium chitosan derivatives (Q- CDs), such as 96% deacetylated chitin hydrochloride (DAC-96.HCl), partially O-methyl-N-trimethylated chitosan chloride (O-Me;M-TM [Cl-]), and partiall y N,O-(2-hydroxy-3-trimethylammonio)propylated chitosan chloride (N,O-HTMP [Cl-]), N-MP [CI] showed the lowest specific resistance (rho). N-TMPB [Cl-] whose rho was comparable with that of N-TM [Cl-] showed lower water conten t compared with known Q-CDs noted above. Newly prepared Q-CDs thus appear a s promising biocompatible antistatic materials.