Chiral recognition models for the liquid chromatographic resolution of π-acidic racemates on a chiral stationary phase derived from N-phenyl-N-alkylamide of (5')-naproxen

摘要

To elucidate the chiral recognition mechanism exerted by an (S)-naproxen-derived chiral stationary phase (CSP) containing a long tether consisting of a tertiary N-phenyl-N-undecyl amide linkage, a CSP with a short tether consisting of N-phenyl-N-propyl amide linkage was prepared and homologous series of N-(3,5-dinitrobenzoyl)-a-amino alkyl esters and N-(3,5-dinitrobenzoyl)-α-(4-alfcylphenyl)alkylamines were resolved on the two CSPs. Based on the chiral recognition trends for resolving homologous series of π-acidic racemates on the two CSPs which differ only in the tether length and from the study of CPK space filling molecular models, chiral recognition models utilizing the intercalation of the alkyl substituent of the analyte between the adjacentstrands of bonded phase in rationalizing the dependence of the separation factors on the length of the alkyl substituent of the analyte and the tether length of the CSP were proposed.