Preparation and evaluation of new chiral stationary phases for high-performance liquid chromatographic separation of enantiomers : Comparison of enantiomeric and diastereomeric phases based on (α)-1-napththylethylamine for the resolution of derivatives of amino acid enantiomers

Abstract

Three new chiral stationary phases [two diastereomeric phases based on R-phenylglycyl- R/S-(α)-1-napththylethylamide and one enantiomeric phase based on glycycl- S-(α)_-1-napththylethylamide] have been prepared and evaluated. There were marginal differences betwen the phases for the separation of enantiomers of 3,5-dinitrobenzoyl amino acid esters when used in conjunction with isopropanol—hexane mobile phases. However, there were marked differences when dichloromethane—hexane mobile phases were used. With the latter mobile phase the R/R chiral support did not separate any of the derivatives into their enantiomers and the R/S chiral support gave larger separation factors than the enantiomeric ( S) phase. The R/S chiral support gave comparable separation factors with either dichloromethane or isopropanol containing mobile phases. The R/R chiral phase gave the largest separation fctor for the enantiomers of the N-α-3,5-dinitro benzoyl derivative of ethyl-α-amino-2-imidazolepropionate (isohistidine ethyl ester).