(3S,4aS,8aS,2'R,3'S,3S,4aS,6aR)-N-tert-Butyl-2-[2'-hydroxy-4'-phenyl-3'-[[[(4-hexahydrofuro[3,4-b]furanyl)oxy]carbonyl]amino]butyl]decahydroisoquinoline-3-carboxamide AIDS-028268 AIDS028268 IsoquinCON Thf-Thf Urethane analog