Isolation and Structures of Euphohelins, New Toxic Diterpenes from Euphorbia Helioscopia L.

Five new toxic diterpenes, euphohelins A, B, C, D, and E, have been isolated from the plant Euphorbia helioscopia L., and their stereostructures have also been elucidated on the basis of their spectral data coupled with some chemical evidence: euphornin, the known toxic diterpene, has been successfully converted into euphohelin A.