(4S)-4-{N-[(1S)-1-(N-{(1S)-1-[N-((1S)-1-{[(5S,1R)-8-Ethyl-6-(methylsulfonyl)-7-oxo-2,6-diazabicyclo[3.3.0]oct-2-yl]oxycarbonyl}-2-methylpropyl)carbamoyl]-2-methylpropyl}carbamoyl)-2-carboxyethyl]carbamoyl}-4-(acetylamino)butanoic acid AIDS-154663 AIDS154663