2-({(3aR,45,6R,6aS)-6-[7-{[[N-(1R,2S)-2-(3,4-difluorophenyl)-cyclopropan-1-yl]-N-tert-butoxycarbonyl]amino}-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]-2,2-dimethyl-tetrahydro-3aH-cyclopenta[d][1,3]dioxol-4-yl}oxy)-O-tertbutoxycarbonylethanol