N-[4-(6-Methoxy-2-benzoxazolyl)]benzoyl-L-amino Acids as Chiral Derivatization Reagents for Amine Enantiomers

Abstract

N-[4-(6-Methoxy-2-benzoxazolyl)]benzoyl-L-phenylalanine (BOX-L-Phe) and N-[4-(6-methoxy-2-benzoxazolyl)]benzoyl-L-proline (BOX-L-Pro) have been synthesized to permit separation of amine enantiomers by high-performance liquid chromatography. Enantiomeric amines were readily condensed with the chiral derivatization reagents in the presence of 2, 2′-dipyridyl disulfide and triphenylphosphine. The diastereomeric BOX-L-Pro amides were separable by both normal-phase and reversed-phase chromatography. They could be sensitively detected fluorometrically at 432nm, with excitation at 325nm in the reversed-phase mode. The detection limit of the BOX-L-Pro derivative ofR-1-(1-naphthyl)ethylamine was 30fmol at a signal-to-noise ratio of 3.