(S)-3-{[2-((S)-1-tert-Butoxycarbonylamino-ethyl)-thiazole-4-carbonyl]-amino}-pentanoic acid

(S)-3-{[2-((S)-1-tert-Butoxycarbonylamino-ethyl)-thiazole-4-carbonyl]-amino}-pentanoic acid (S)-1-({(S)-1-[((S)-1-tert-butoxycarbonyl-2-phenyl-ethyl)-methyl-carbamoyl]-2-methyl-propyl}-methyl-carbamoyl)-ethyl ester