1,10-Epoxycostunolide AIDS-059916 AIDS059916 Oxireno[5,6]cyclodeca[1,2-b]furan-7(2H)-one, 1a,3,5a,8,8a,9,10,10a-octahydro-4,10a-dimethyl-8-methylene-, (1aR,4E,5aR,8aS,10aS)-