(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

N,N'-bis-Boc-S-methyl-isothiourea