11,12-Epoxypukalide 11,16,18,19-Tetraoxapentacyclo(12.2.2.1(6,9).0(1,15).0(10,12))nonadeca-6,8-diene-7-carboxylic acid, 12-methyl-4-(1-methylethenyl)-17-oxo-, methyl ester, (1R-(1R*,4S*,10R*,12S*,14R*,15R*))- 95925-22-7