Preparation of Haloacyl Derivatives of Chitosan

Abstract

A novel method for the preparation of haloacyl derivatives of chitosan under mild conditions is described. To a solution of chitosan (0.16 g) in a halocarboxylic acid (-7 ml) was added a halocarboxylic anhydride (3, -5 ml). The mixture was allowed to stand at 75-80°C for a few minutes to two hours or at room temperature for 18 h. N, O-Acyl derivatives (d. s.1.2-3.0/G1cN) were produced and isolated in 72-97% yield Their O-deacylation with alk ali afforded N-trifluoroacetyl, N-chloroacetyl and N-formyl derivatives (d. s, =1.0/G1cN) in 7586% yield. The N-trifluoroacetyl gorup was unstable to alkali. All the products were insoluble in water and in common organic solvents.