pyridin-2-ylmethyl N-[(1S)-1-[[(2S,5S)-3,3-difluoro-5-[[(2S)-3-methyl- 2-(pyridin-2-ylmethoxycarbonylamino)butanoyl]amino]-4-oxo-1,6-diphenyl -hexan-2-yl]carbamoyl]-2-methyl-propyl]carbamate