3,13,16-Trioxatetracyclo[10.2.1.17,10.02,4]hexadeca-1(15),7,9-triene-8-carboxylic acid, 5,11-bis(1-methylethenyl)-14-oxo-, methyl ester, (2R*,4S*,5S*,11S*,12S*)- 3,16,16-Trioxatetracyclo[10.2.1.17,10.02,4]hexadeca-1(15),7,9-triene-8-carboxylic acid, 5,11-bis(1-methylethenyl)-14-oxo-, methyl ester 83560-98-9 NSC344015