N-(tert-butoxycarbonyl)-L-seryl-L-alanyl-N-{(1S,2R)-1-benzyl-2-hydroxy-2-[(1S,2S)-2-{[(1S)-1-{[(1S)-1-(methoxycarbonyl)-2-methylpropyl]carbamoyl}-2-methylpropyl]carbamoyl}cyclopentyl]ethyl}-L-alaninamide