Liquid chromatographic separation of amino acid enantiomers on a silica-bonded chiral s-triazine column

Abstract

A chiral derivatizing reagent (CDR) was synthesized by consecutive nucleophilic replacement of two chlorine atoms in 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride) by l-valinamide and l-phenylalaninamide, yielding N-[4-((S)-1- carbamoyl-2- methyl-propylamino)-6- chloro-[1,3,5] triazin-2- yl]- l- phenylalanine . This CDR was used for the derivatization of free dl-amino acids, followed by the liquid chromatographic separation of the diastereomers thus formed, and for the synthesis of a chiral stationary phase (CSP). The CSP was synthesized by substitution of the remaining chlorine atom with aminopropylsilica, yielding {3-[4-(( S)-1-carbamoyl-2-methyl-propylamino)-6-(( S)-1-carbamoyl-2-phenyl-ethylamino)-[1,3,5] triazin-2-ylamino]-propyl}-functionalized silica gel. This new CSP was found to effect, in part very high, resolutions for enantiomers of dansylamino acids when mixtures of acetonitrile and 0.01 M sodium acetate buffer (pH 4) were used as eluents.