tert-butyl 4-(4-(4-(2-((S)-1-((R)-2-(dimethylamino)-2-phenylacetyl)pyrrolidin-2-yl)-1H-imidazol-4-yl)phenylcarbamoyl)-2-(7-isopropylpyrido[2,3-d]pyrimidin-4-ylamino)phenylthio)phenylcarbamate