Trifluoroacetic acid → 2-({2,2,2-Trifluoro-1-[3-(trifluoromethyl)phenyl]ethyl}carbamoyl)-1-benzofuran-6-carboxylic acid

A solution of tert-butyl 2({2,2,2-trifluoro-[3-(trifluoromethyl)phenyl]ethyl}carbamoyl)-1-benzofuran-6-carboxylate (450 mg, 1.04 mmol) in dichloromethane (4.5 ml) was admixed at 0° C. with trifluoroacetic acid (0.46 ml, 6.0 mmol) and stirred at room temperature overnight. Subsequently, the reaction mixture was washed with water, and the organic phase was dried over magnesium sulphate, filtered and concentrated under reduced pressure. The residue was filtered through silica gel, the filtercake was rinsed with ethyl acetate and methanol, and the filtrate was concentrated.