Synonyms: 2-Butenoicacid, 2-methyl-,1,2,3,4,6,7,8,8a-octahydro-1,8a-dimethyl-7-(1-methylethylidene)-6-oxo-2-naphthalenylester, [1R-[1a,2b(Z),8aa]]-; Eremophila-7(11),9-dien-8-one, 3a-hydroxy-, 2-methylcrotonate,(Z)- (8CI); Isopetasin (6CI); Crotonic acid, 2-methyl-, ester with 3a-hydroxyeremophila-7(11),9-dien-8-one,(Z)- (8CI); (+)-Isopetasin; Isopetasyl cis-2-methyl-2-butenoate