(1S,5bS,8S,10aS,11S,11aR,13R)-8,13-dihydroxy-1-methyl-9-methylene-2-oxo-2,5a,5b,6,7,8,9,10,11,11a-decahydro-1H-1,4:8,10a-dimethanoazuleno[1,2-d]oxepine-11-carboxylicacid