2-Butenoic acid, 2-methyl-, 5-hydroxy-3-methyl-1-[tetrahydro-2-(3-hydroxy-2-methyl-1-propenyl)-4-methylene-5-oxo-3-furanyl]-3-pentenyl ester, [2R-[2.alpha.(E),3.beta.[1R*(Z),3E]]]- 55306-05-3 NSC249958 Pycnolide