(4S)-4-[[(2R)-(4-Fluoro-benzyl)-6-methyl-(5S)-5-(methyl-isoxazole-3-carbonyl)-amino]-[4-oxo-heptanoylamino]-5-(2-oxo-piperidin-(3S)-3-yl)]-pent-2(E)-enoic acid, ethyl ester AIDS-163876 AIDS163876