High-pressure liquid chromatographic resolution of amino acid enantiomers by derivatization wtth'new chiral reagents

Abstract

A new derivatization procedure has been developed for converting enantiomeric amino acids into diastereomers for resolution'by high-pressure liquid chromatography. Two chiral derivatization reagents, (—)-1,7-dimethyl-7-norbornyl isothiocyanate and (+)-neomenthyl isothiocyanate, were synthesized from the corresponding amines. Amino acids were readily transformed with the chiral reagents into the thiourea derivatives which absorb at 243 nm (ϵ=17,000). The tert-butyldimethylsilyl esters of the diastereomeric thiourea derivatives were efficiently resolved by normal phase chromatography (μPorasil column) with cyclohexane/ethyl acetate as a mobile phase.