Separation of the Enantiomers of β-Blockers Using Brush Type Chiral Stationary Phase Derived from Conformationally Rigid α-Amino β-Lactam

A brush type chiral stationary phase (CSP 2) derived from alpha-amino beta-lactam was prepared for the separation of the enantiomers of beta-blockers. Compared to the CSP derived from alpha-amino phosphonate (CSP 1), in general, the conformationally rigid CSP 2 showed greater scope and much enhanced enantioselectivity for the resolution of beta-blockers. The effect of various salt additives on enantioseparation of beta-blockers in the mobile phase was investigated. The unusual effect of temperature on the chromatographic behaviors was observed on CSP 2. It also afforded appreciable increases in enantioselectivity without significantly affecting resolution, as the column temperature was reduced.