Powdered potassium hydroxide (111 mg, 1.98 mmol) was added in one portion to methyl 2-(4′-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2′,6′-difluorobiphenyl-4-yl)acetate (Intermediate 2-1; 295 mg, 0.66 mmol) in tert-butanol (10 mL) at 50° C. The resulting solution was stirred at 50° C. for 45 minutes, 2M HCl (2 mL) was added and the mixture was evaporated to remove the organic solvent. The suspension was collected by filtration, washed with water (50 mL) and air dried to afford 2-(4′-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-chloro-2′,6′-difluorobiphenyl-4-yl)acetic acid (220 mg, 77%) as a cream solid.
