Isoterracinolides A and B, novel bishomoditerpene lactones from Euphorbia terracina

An extract of Euphorbia terracina L. has yielded six acylated polyhydroxy t erpenoid lactones (1-6), which all display the C-22 17-ethyljatrophane carb on framework. Four of these (1-4) are delta lactones belonging to the previ ously described terracinolide type, and two of them (2, 3) are new. Two fur ther new compounds have been named isoterracinolides A (5) and B (6) and ex hibit an eight-membered lactone ring. Another isolated new compound is the jolkinolide-type, ent-abietane gamma lactone (7).