3-fluoro-, 3-chloro- and 3-bromo-5-methylphenylcarbamates of cellulose and amylose as chiral stationary phases for high-performance liquid chromatographic enantioseparation

3-Fluoro-, 3-chloro- and 3-bromo-5-methylphenylcarbamates of cellulose and amylose were prepared and their chiral recognition abilities as chiral stationary phases for high-performance liquid chromatography (HPLC) were evaluated and compared with those of the 3,5-difluoro-, 3,5-dichloro- and 3,5-dimethylphenylcarbamates of cellulose and amylose. The introduction of both an electron-donating methyl group and an electron-withdrawing halogen group onto the phenyl moieties markedly modified the polarities of the carbamate residues. Among the cellulose derivatives, cellulose tris(3-fluoro-5-methylphenylcarbamate) showed an excellent chiral recognition ability and resolved some racemates better than the corresponding 3,5-difluoro- and 3,5-dimethylphenylcarbamates of cellulose. The amylose derivatives exhibited a characteristic chiral recognition depending on the substituents. The effects of substituents on chiral discrimination is discussed on the basis of enantioseparation results in HPLC, IR, H-1 NMR and circular dichroism (CD) data. Some chiral drugs were better resolved on cellulose tris(3-chloro-5-methylphenylcarbamate) than cellulose tris(3, 5-dimethylphenylcarbamate). (C) 1997 Elsevier Science B.V.