Enantiomeric high-performance liquid chromatographic separation of beta-substituted tryptophan analogues

The high-performance liquid chromatographic enantioresolution of beta-subst ituted tryptophan analogues by direct and indirect methods is reported. The direct separation was carried out on chiral crown ether-bonded, on the mac rocyclic antibiotic teicoplanin-bonded or on different derivatized beta-cyc lodextrin-bonded phases. The indirect resolution was achieved by applying p re-column derivatization with the chiral reagents 1-fluoro-2,4-dinitropheny l-5-L-alanine amide (FDAA) and 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC). In the separation of all four isomers of the analyt es, the indirect methods seemed to be more efficient than the direct method s. In most cases, the FDAA derivatives of the stereoisomers could be separa ted with better selectivity in methanol-containing mobile phases.