(3S,4aS,8aS,2'R,3'S)-N-tert-Butyl-2-[2'-hydroxy-4'-phenyl-3'-[[[(3a-hexahydrofuro[2,3-b]furanyl)oxy]carbonyl]amino]butyl]decahydroisoquinoline-3-carboxamide AIDS-028267 AIDS028267 IsoquinCON Urethane analog