A stem extract of Kopsia larutensis furnished in addition to kopsinine, seven other alkaloids of the eburnane type including (+)-eburnamonine and its N(4)-oxide, (-)-eburnamine, (+)-isoeburnamine, (-)-O-ethyleburnamine, (+)-eburnamenine and larutenine. Single crystal X-ray diffraction analysis was carried out on (-)-O-ethyleburnamine and (+)-isoeburnamine from which the absolute configuration of C-16 of these and other eburnane alkaloids was established. © 1993.