Derivation of Diastereomeric Schiff-Base Copper-Chelates from α-Amino-Acid Racemates and Their Chromatographic Separation

Salicylaldehyde and pyridoxal derivatives carrying optically active residue were applied for the derivation of Schiff base copper chelates from α-amino acids. In aqueous media the chelate formation process proceeded spontaneously and the process was reversed by the addition of EDTA. Thus the applicabilities of the process to the method for the resolution of alpha-amino acids were investigated. Chromatographic separation of the chelates from pyridoxal derivative on a reverse-phase column was found to be successful. The separation of two elution peaks within a pair of enantiomers was excellent for most of amino acids although some improvement is required for the separation of amino acids with acidic or basic side chain.