PREPARATION OF A NEW HPLC CHIRAL STATIONARY-PHASE FROM (S)-NAPROXEN AND APPLICATION IN ELUCIDATING CHIRAL RECOGNITION MODELS

A new HPLC chiral stationary phase (CSP 3) has been prepared by connec ting N-phenyl N-propyl amide of (S)-naproxen to silica gel through the 6-methoxy-2-naphthyl group of (S)-naproxen. The new CSP has been appl ied in resolving a homologous series of N-(3,5-dinitrobenzoyl)-alpha-a mino acid esters and a homologous series of -dinitrobenzoyl)-alpha-(4- alkylphenyl)alkylamines. The separation factors, alpha, for resolving a homologous series of N-(3,5-dinitrobenzoyl)-alpha-amino esters and a homologous series of 5-dinitrobenzoyl)-alpha-(4-alkylphenyl)alkylamin es on the new CSP have been found to remain almost constant throughout the wide range of the length of the alkyl substituent of the analytes while those on the previously reported CSPs (CSP 1 and 2) which were prepared by connecting N-phenyl N-propyl amide of (S)-naproxen to sili ca gel through the N-propyl group increase or decrease continuously. T hese results are concluded to support the chiral recognition models wh ich utilize the intercalation of the alkyl substituent of the racemic analytes between the adjacent strands of CSP 1 or 2 to rationalize the increasing or decreasing trends of separation factors.