4-{N-[1-(N-{1-[N-({N-[(3E)(1S)-1-Ethyl-4-(4-methoxyphenyl)-2-oxobut-3-enyl]carbamoyl}(1S)cyclohexylmethyl)carbamoyl](1S)-2-methylbutyl}carbamoyl)(1S)-3-methylbutyl]carbamoyl}(4R)-4-[(2S)-2-(acetylamino)-3-carboxypropanoylamino]butanoic acid AIDS-169903 AIDS169903