HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR THE SEPARATION OF THE OPTICAL ISOMERS OF MMA,GAMMA'-DI-TERT-BUTYL-D,L-GAMMA-CARBOXYGLUTAMIC ACID AND D,L-GAMMA-CARBOXYGLUTAMIC ACID

The chemical synthesis of gamma,gamma'-di-tert.-butyl-gamma-carboxyglu tamic acid is accompanied by extensive racemization, and very careful resolution is needed to obtain D- and -gamma,gamma'-di-tert.-butyl-gam ma-carboxyglutamic acids in high chiral purity. A novel method was dev ised for the separation of enantiomers of gamma,gamma'-di-tert.-butyl- gamma-carboxyglutamic acid and gamma-carboxyglutamic acid, applying pr ecolumn derivatization with 1-fluoro-2,4-dinitrophenyl-5-L-alanine ami de and 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate as chiral reagents, with subsequent reversed-phase high-performance liqui d chromatographic separation of diastereomeric compounds. The effects of organic modifiers, of the mobile-phase composition and of the pH on the separation of the diastereomers were investigated.