Chemical modification of chitin and chitosan 1: preparation of partially deacetylated chitin derivatives via a ring-opening reaction with cyclic acid anhydrides in lithium chloride/N,N-dimethylacetamide

Derivatives of partially N-deacetylated chitin (DAC) were prepared via ring-opening reactions with various cyclic acid anhydrides in lithium chloride/N,Ndimethylacetamide (LiCl/DMAc) system. Some cyclic acid anhydrides such as succinic, maleic, glutaric, and phthalic anhydrides gave successfully water-soluble DAC derivatives. From the enzymatic studies, the glycosyl bond of succinyl and maleoyl DAC-20 (20% DAC) was rapidly degraded by lysozyme or chitinase, though that of phthaloyl DAC-20 was not. The ester linkage of succinyl DAC-20 was stable against lipase for five days at room temperature.