To a mixture of 1-(6-amino-4-chloro-3′-fluoro-5-methylbiphenyl-2-yl)ethanone (100 mg, 0.4 mmol) and 4-dimethylaminopyridine (52.8 mg, 0.432 mmol) in tetrahydrofuran (1 mL) was added 4-chlorobutanoyl chloride (0.044 mL, 0.40 mmol). The reaction was stirred at room temperature for 1 hour. Potassium tert-butoxide (1.0 M) in tetrahydrofuran (0.79 mL, 0.79 mmol) was added and the resulting mixture was stirred at room temperature for 2 hours, then quenched with aq. ammonium chloride and extracted with ethyl acetate. The combined organic layers were washed with water, brine, dried and evaporated. The resulting residue was purified on silica gel, eluting with 0 to 50% ethyl acetate in hexane, to give the product (40 mg, 30%). LCMS calculated for C19H18ClFNO2 (M+H)+: m/z=346.1. found: 346.1.
