High-performance liquid chromatographic enantioseparation using chitin carbamate derivatives as chiral stationary phases

Chitin carbamate derivatives including 4-substituted and 3,5-disubstituted phenylcarbamates, 1-phenylethylcarbamates, and cycloalkylcarbamates were synthesized and coated on macroporous silica gel to evaluate their chiral recognition abilities as chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). Among the derivatives, the 3,5-dimethylphenyl, 4-chlorophenyl, and 4-trifluoromethylphenylcarbamates showed relatively high-chiral recognition abilities when a hexane–2-propanol mixture was used as the eluent. The CSPs based on the chitin 3,5-dimethylphenyl and 3,5-dichlorophenylcarbamates could be stably used in the presence of chloroform and ethyl acetate as a component of the eluents, and a few racemates were more sufficiently resolved by the addition of a small amount of chloroform in the mobile phase. Some racemates were more efficiently resolved under the reversed phase condition.