found in Uncaria attenuata, was prepared from isorhynchophylline (2), and two diastereomers ascribable to C7 of the natural and semi-synthetic 1 were separated by chiral column chromatography. The absoluteconfiguration at C7 was elucidated by comparison of the CDspectra with those of the known oxytryptophan derivatives (8a and 8b). Further, the absoluteconfiguration of some natural products having