Facile acylation of α-chitin in ionic liquid

Based on the fact that an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), efficiently dissolved α-chitin, this study investigated the development of facile acylation reactions of α-chitin in AMIMBr media. Under optimal conditions in the presence of pyridine and N,N-dimethyl-4-aminopyridine as base and catalyst, respectively, lauroylation of α-chitin smoothly took place using lauroyl chloride in AMIMBr at 100 °C for 24 h to produce a chitin laurate with a high degree of substitution (DS). Chitin acylates having different substituents were also synthesized by acylation of α-chitin using various acyl chlorides under the same conditions. In addition to IR analysis of the products, 1H NMR measurement was allowed for structure confirmation owing to the dissolution of the high DS derivatives in CDCl3/CF3CO2H mixed solvents.