(8r,9s,12as,14ar,18r)-9-methyl-1,2,7,8,9,10,12a,13,14,14a,15,16-dodecahydro-3h,6h,12h-8,11,17b-(methanetriyl)oxepino[4',3':4,5]azuleno[6,5-c]azonin-3-one