18-crown-6-2-3-11-12-tetracarboxylic-acid and pipecolic-acid

Two liquid chromatographic chiral stationary phases based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid were applied to the resolution of the amide derivatives of cyclic α-amino acids including proline and pipecolic acid. Among the five amide derivatives of proline, aniline amide was resolved best on the first chiral stationary phase, which contains two N-H tethering amide groups, with the separation factor of 1.31 and the resolution of 2.60, and on the second chiral stationary phase, which contains two N-CH

Topics: Chromatography, High Pressure Liquid; Crown Ethers; Molecular Structure; Pipecolic Acids; Proline; Stereoisomerism