BIS THF Nitro Derivative 1

(3S,3aR,6aS)-Hexahydrofuro[2,3-b]furan-3-yl 4-nitrophenyl ester carbonic acid is an impurity of bis-THF-derived compounds (such as [1-benzyl-2-hydroxy-3-(arylsulfonamido)propyl]carbamates) that act as HIV-aspartyl protease inhibitors.