{3-[(S)-1-[(R)-2-((S)-2-Acetylamino-4-carbamoyl-butyrylamino)-3-(4-fluoro-phenyl)-propionyl]-4-((S)-1-methylcarbamoyl-2-naphthalen-2-yl-ethyl)-3-oxo-piperazin-2-yl]-propyl}-carbamic acid benzyl ester

(S)-2-[(S)-4-[(R)-2-Acetylamino-3-(4-fluoro-phenyl)-propionyl]-3-(3-amino-propyl)-2-oxo-piperazin-1-yl]-N-methyl-3-naphthalen-2-yl-propionamide

[(R)-2-[(S)-2-(3-Amino-propyl)-4-((S)-1-methylcarbamoyl-2-naphthalen-2-yl-ethyl)-3-oxo-piperazin-1-yl]-1-(4-fluoro-benzyl)-2-oxo-ethyl]-carbamic acid tert-butyl ester

(S)-2-[(S)-4-{(R)-2-[(S)-2-Acetylamino-3-(4-hydroxy-phenyl)-propionylamino]-3-phenyl-propionyl}-3-(3-amino-propyl)-2-oxo-piperazin-1-yl]-N-methyl-3-naphthalen-2-yl-propionamide