Chemical modification alkylated chitosans

Sashiwa, H. and Shigemasa, Y. 1999. Chemical modification of chitin and chitosan. 2 Preparation and water soluble property of N-acylated or N-alkylated partially deacetylated chitins. Carbohydr. Polym. 39 127-138. 

The antibacterial effects of the chemical modifications, long alkyl chains (until C12), the antibacterial activities of the quaternary ammonium salt of chitosan, and biocidal activity have also been studied and compared elsewhere. 

Chemical. A large number of chitin and chitosan derivatives have been synthesized through modification of the primary (C-6) and secondary (C-3) hydroxyl groups present on each repeat imit, including amine (C-2) functionality existing on deacetylated imits (31). Reactions typical of hydroxyl and amine groups (such as acylations with acid chlorides and anhydrides) including urethane and urea formation respectively, are feasible with isocyanates. The primary amine can be quatemized by alkyl iodides or converted to an imine with a variety of aldehydes and ketones that can subsequently be reduced to an N-alkylated derivative. Chitin and chitosan are reactive with a variety of alkyl chlorides after treatment with concentrated NaOH. Important derivatives such as carboxymethylated chitin and chitosan are commonly produced in this manner with the addition of sodium chloroacetate. 

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