(4S)-4-[N-((1S)-1-{N-[(1S)-2-((2S)-2-{[(5S,1R)-8-Ethyl-6-(methylsulfonyl)-7-oxo-2,6-diazabicyclo[3.3.0]oct-2-yl]oxycarbonyl}pyrrolidinyl)-1-(methylethyl)-2-oxoethyl]carbamoyl}-2-carboxyethyl)carbamoyl]-4-(acetylamino)butanoic acid AIDS-154666 AIDS154666