β-3-Oxindolylalanine (hydroxytryptophan). 2. Spectroscopic and chromatographic properties

Abstract

The RF values of beta-oxindolylalanine, tryptophan and kynurenine were measured employing various solvent mixtures. With the usual systems resolution was poor; however, separation was obtained with a butanol-acetic acid mixture containing formaldehyde. The u.-v. absorption spectra of a number of oxindole derivatives including beta-oxindolylalanine were measured. Addition of alkali was found to produce various reversible and irreversible changes which were correlated with the mode of substitution. A comparison of the reported absorption spectra of phalloidin (from Amanita phalloides) with those of oxindole derivatives indicates that the oxindole structure is not present as such in phalloidin.