The structure and absolute stereochemistry of a new diterpenoid alkaloid, barbaline, was determined by NMR spectroscopy techniques and single-crystal X-ray diffraction analysis.
Manners, G. D., Wong, R. Y., Benson, M., Ralphs, M. H., & Pfister, J. A. (1996). The characterization and absolute stereochemistry of barbaline, a diterpenoid alkaloid from Delphinium barbeyi. Phytochemistry, 42(3), 875–879. https://doi.org/10.1016/0031-9422(95)00009-7