Dependence of enantioseparation performance on structure of chiral selectors derived from N-cycloalkylcarbonyl chitosan

In order to study dependence of enantioseparation capability on structure of chiral selectors derived from N-cycloalkylcarbonyl chitosan, nine chitosan 3,6-bis(arylcarbamate)-2-(cyclopentylformamide)s were synthesized. The corresponding chiral stationary phases (CSPs) were prepared with the chitosan derivatives. Enantioseparation capability of the CSPs was evaluated under the same conditions with the same chiral analytes. Different from CSPs derived from cyclopropylcarbonyl, cyclobutylcarbonyl and cyclohexylcarbonyl chitosans, all the CSPs with halo and methyl substituents in the present work showed good enantioseparation capability. Therefore, N-cyclopentylcarbonyl chitosan is more preferable to be used to develop enantiomeric separation materials among N-cycloalkylcarbonyl chitosans. Besides, the chitosan derivatives in this study and cellulose Iris (3,5-dimethylphenylcarbamate) are complementary in enantioseparation for some chiral analytes. It was also observed that the chitosan derivative with 3,4-dichlorophenyl substituent baseline separated the most chiral analytes, thus revealing that this substituent can be applied as a building block to construct enantiomeric separation materials.