Serrulatin A and B, New Diterpene Polyesters from Euphorbia serrulata

Two new diterpene polyesters, serrulatin A (1) and B (2), were isolated from an n-hexane extract of the whole, undried plant of Euphorbia serrulata. The structures were elucidated by various spectroscopic methods, including ESI-MS, IR, UV, 1D and 2D NMR techniques and X-ray crystallography. Serrulatin A contains a hitherto unknown heterocyclic ring system, while serrulatin B is a diterpene, which can be formally derived from 1 by ring opening.