acetic acid 4-{[(2′S,3′R,4′S,5′R)-1,1′-diacetyl-6-chloro-4′-(3-chloro-2-fluoro-phenyl)-2′-(2,2-dimethyl-propyl)-2-oxo-1,2-dihydro-spiro[indole-3,3′-pyrrolidine]-5′-carbonyl]-amino}-cyclohexyl ester