(S)-2,6-Bis-benzyloxycarbonylamino-hexanoic acid 3,5-dioxo-4-aza-tricyclo[5.2.1.02,6]dec-8-en-4-yl ester

{(S)-5-[(S)-1-[(R)-1-({[(S)-1-Benzyl-2-(N'-butyryl-hydrazino)-2-oxo-ethylcarbamoyl]-methyl}-carbamoyl)-ethylcarbamoyl]-2-(4-hydroxy-phenyl)-ethylcarbamoyl]-5-benzyloxycarbonylamino-pentyl}-carbamic acid benzyl ester

(S)-2,6-Diamino-hexanoic acid [(S)-1-[(R)-1-({[(S)-1-benzyl-2-(N'-butyryl-hydrazino)-2-oxo-ethylcarbamoyl]-methyl}-carbamoyl)-ethylcarbamoyl]-2-(4-hydroxy-phenyl)-ethyl]-amide