(3R,4S,6S,6aR,8R,9S,11aS,11bS)-4-[(Acetyloxy)methyl]-4,11b-dimethyldodecahydrospiro[6a,9-methanocyclohepta[a]naphthalene-8,2'-oxirane]-3,6-diyl diacetate AIDS-155564 AIDS155564