Enantiomer separation of amino compounds by a novel chiral stationary phase derived from crown ether

Abstract

A novel chiral stationary phase (CSP-18C6I) was prepared by immobilizing (+)-18-crown-6 tetracarboxylic acid on 3-aminopropylsilanized silica-gel to separate enantiomers of drugs having a primary amino group. The chiral crown ether was combined with 3-aminopropyl silica gel (0.85 mmol of amine per gram of gel) to provide CSP-18C6I having a chiral selector loading of 0.26 mmol per gram of gel. This CSP-18C6I showed good chiral recognition for thirteen out of eighteen dl-amino acids and seven racemic aminoalcohols using a dilute aqueous solution of perchloric acid as the eluent. Afloqualone (a muscle relaxant), primaquine (an antimalarial), and 1-(1-naphthyl)ethylamine (1-NEA) were resolved on the CSP-18C6I. Furthermore, alanine-β-naphthylamide (Ala-β-NA), which is hydrophobic and did not elute within 60 min by the commercially available CROWNPAK CR(+) with 15% methanol and a column temperature of 40°C, was successfully enantioseparated by the novel CSP-18C6I.