Dichloromethane (100 mL) and methanol (50 mL) were added to ((S)-1-{(S)-2-[4-(4′-{[6-((2R,5S)-2,5-dimethyl-4-methylcarbamoyl-piperazin-1-yl)-pyridine-3-carbonyl]-amino}-2′-trifluoromethoxy-biphenyl-4-yl)-1H-imidazol-2-yl]-pyrrolidine-1-carbonyl}-2-methyl-propyl)-carbamic acid methyl ester (10.17 g, 12.40 mmol) and the solution was stirred for 10 min, then cooled to 3° C. and 3 M of HCl in cyclopentyl methyl ether (12.4 mL) was added dropwise keeping the temperature of the reaction mixture less than 10° C. The water bath was removed and the reaction mixture was stirred for 15 min, and concentrated to about 50 mL. Isopropyl acetate was added and the mixture was concentrated to dryness. The resulting material was vacuum dried at RT overnight and vacuum oven dried at RT over the weekend to provide the title compound (12.2 g).
