Bisnorsesquiterpenoids from Euphorbia resinifera Berg. and an expeditious procedure to obtain resiniferatoxin from its fresh latex.

The fresh latex of cultivated E. resinifera Berg. is a convenient source of the ultrapotent vanilloid resiniferatoxin, and a transesterification-reesterification protocol which substantially alleviates the hazard associated with the direct isolation of this obnoxious diterpenoid was developed. Various known phorboid constituents of the diterpenoid fraction were obtained in pure form and spectroscopically characterized for the first time, while the non-diterpenoid fraction of the latex gave, apart from widespread triterpenoids, three new bisnorsesquiterpenes of the dihydroionol-type. The structure of these compounds was established using a combination of spectroscopic data and chemical reactions.