Regioselective chlorination of chitin with N- chlorosuccinimide-triphenylphosphine under homogeneous conditions in lithium chloride-N,N-dimethylacetamide

Purified chitin was chlorinated with an equimolar mixture of N-chlorosuccinimide and triphenylphosphine under homogeneous conditions in a 5% (w/v) solution of LiCl in N, N- dimethylacetamide at 70–55°C. 13C NMR spectroscopy of the chlorinated products and gas chromatographic-mass spectrometric analysis of their hydrolyzates, both as trifluoroacetyl derivatives, showed that the chlorine substitution took place regioselectively at C-6. Chlorodeoxychitins with degrees of substitution up to 1.0 could be prepared easily by use of an excess of reagents. Polymer chain scission took place to some extent, especially when the chlorination was carried out at higher temperatures with higher concentrations of reagents.