tert-butyl N-[(1S)-2-[(1R,2S,5S)-2-[[1-cyclobutyl-4-[[2-[[(1S)-2-(dimethylamino)-2-oxo-1-phenylethyl]amino]-2-oxoethyl]amino]-3,4-dioxobutan-2-yl]carbamoyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexan-3-yl]-1-cyclohexyl-2-oxoethyl]carbamate;tert-butyl N-[(2S)-1-[(1R,2S,5S)-2-[[1-cyclopropyl-4-[[2-[[(1S)-2-(dimethylamino)-2-oxo-1-phenylethyl]amino]-2-oxoethyl]amino]-3,4-dioxobutan-2-yl]carbamoyl]-6,6-dimethyl-3-azabicyclo[3.1.0]hexan-3-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamate