(1alpha,12R,15R)-12,15-Epoxy-1,2,15,20-tetrahydro-C(16a)-homo-21-norsenecionan-11,16a-dione 50906-96-2 C(16a)-Homo-21-norsenecionan-11,16a-dione, 12,15-epoxy-1,2,15,20-tetrahydro-, (1alpha,12R,15R)- Nemorensine