benzyl [(2S)-1-{[(2S,3R,4R)-4-(benzylamino)-5-{[(2S)-1-(benzylamino)-3,3-dimethyl-1-oxobutan-2-yl]amino}-3-hydroxy-5-oxo-1-phenylpentan-2-yl]amino}-3-methyl-1-oxobutan-2-yl]carbamate (non-preferred name)