(+/-)-10,11-cis,11,12-cis-10,11-Dihydro-12-hydroxy-10-isopropyl-4-propyl-6,6,11- trimethyl-2H,6H,12H-benzo-[1,2-b:3,4-b':5,6-b'']tripyran-2-one AIDS-058245 AIDS058245 Calanolide analog