Synonyms: 2-Butenoicacid, 2-methyl-,3,3a,4,5,6a,7,9a,9b-octahydro-9-methyl-3-methylene-2,7-dioxospiro[azuleno[4,5-b]furan-6(2H),2'-oxiran]-4-ylester, [3aR-[3aa,4b(E),6a,6aa,9aa,9bb]]-; Spiro[azuleno[4,5-b]furan-6(2H),2'-oxirane],2-butenoic acid deriv.; Eupasessifolide A