Chlorination of chitin with sulfuryl chloride under homogeneous conditions

Chitin was chlorinated with sulfuryl chloride under homogeneous conditions in LiCl-N,N-dimethylacetamide. Chlorodeoxychitins were obtained in the reactions at temperatures from −30 to 70 °C. The regioselective replacement of C-6 hydroxyl groups with chlorine atoms occurred in the reaction for 4 h at −20 °C while C-3 hydroxyl groups were also replaced above 0 °C when the molar ratio of sulfuryl chloride to the repeating unit of chitin was 15. The yield of chlorodeoxychitin decreased from 90 to 60% with the rise in reaction temperature from −30 to 60 °C and dropped to 27% at 70 °C. All the chlorodeoxychitin samples were soluble in formic acid.