Capillary zone electrophoresis study of naphthylethylcarbamoylated beta-cyclodextrins

Regiospecifically monosubstituted 1-(1-naphthyl)ethylcarbamoylated beta-cyclodextrins (NEC-beta-CDs) were successfully employed as chiral additives in capillary zone electrophoresis (CZE) to achieve chiral separation of N-(3,5-dinitrobenzoyl)phenylglycine (3,5-DNB-PG), phenylalanine (3,5-DNB-PA), and homophenylalanine (3,5-DNB-HPA). The enantioselectivity of the various site-substituted NEC-beta-CDs in CZE was compared with that of native beta-CD. Complexation constants of the three 3,5-DNB amino acids with beta-CD were determined from the CZE results: 3,5-DNB-L-HPA, 473 +/- 9 M-1; 3,5-DNB-D-HPA, 460 +/- 10 M-1; 3,5-DNB-L-PA, 260 +/- 4 M-1; 3,5-DNB-D-PA, 161 +/- 3 M-1; and 3,5-DNB-D, L-PG, 43 +/- 4 M-1.