(3R,3aS,6aR)-Hexahydrofuro[2,3-b]furan-3-yl [(1S,2R)-1-benzyl-2-hydroxy-3-(isobutyl{[1-(2-phenylethyl)-1H-benzimidazol-6-yl]sulfonyl}amino)propyl]carbamate AIDS-223661 AIDS223661