A 1M solution of NaOH (1.877 mL, 1.877 mmol) was added to a solution of ethyl 6-(N-(4-bromo-3-chlorophenyl)methylsulfonamido)-2-(4-chlorophenyl)-5-cyclopropylbenzofuran-3-carboxylate (234 mg, 0.375 mmol) in THF (2 mL) and MeOH (1 mL) at RT. After 1 h a white precipitate formed but starting material is still evident by LCMS. THF (3 mL) and a 4N solution of NaOH (1 mL) were added and the mixture was heated to 60° C. for 4 h. EtOAc was added and the aqueous layer was made acidic with the addition of 1N HCl. The organic layer was separated, washed with water, brine, dried over Na2SO4, filtered and concentrated to give 6-(N-(4-bromo-3-chlorophenyl)methylsulfonamido)-2-(4-chlorophenyl)-5-cyclopropylbenzofuran-3-carboxylic acid (220 mg, 0.351 mmol, 94% yield) as a white solid. LCMS (m/z, ES+)=594.0 (M−H).
