(S)-[2-(3-{(S)-2-[((S)-2-Cyclohexyl-2-isobutoxycarbonylamino-acetyl)-methyl-amino]-3-cyclopropyl-propionylamino}-4-cyclopropyl-2-oxo-butyrylamino)-acetylamino]-phenyl-acetic acid tert-butyl ester

(S)-2-(tert-Butoxycarbonyl-methyl-amino)-3-cyclopropyl-propionic acid methyl ester

(2S)-2-[[(tert-butoxy)carbonyl](methyl)amino]-3-cyclopropylpropanoic acid

((S)-3-tert-Butoxycarbonylamino-4-cyclopropyl-2-hydroxy-butyrylamino)-acetic acid

((S)-2-Acetoxy-3-tert-butoxycarbonylamino-4-cyclopropyl-butyrylamino)-acetic acid methyl ester