4-[N-(1-{N-[1-(N-{1-[N-((1R)-1-Carboxy-2-sulfanylethyl)carbamoyl](1S)-2-cyclohexylethyl}carbamoyl)(1S)-2-carboxyethyl]carbamoyl}(1S)-2,2-diphenylethyl)carbamoyl](4S)-4-[(2S)-2-(acetylamino)-3-carboxypropanoylamino]butanoic acid AIDS-105128 AIDS105128 Ac-D-E-Dif-D-Cha-C-OH