To a mixture of 1-(6-amino-4-chloro-3′,5′-difluoro-5-methylbiphenyl-2-yl)ethanone (0.10 g, 0.34 mmol) and pyridine (0.041 mL, 0.51 mmol) in methylene chloride (2 mL) was added 4-chlorobutanoyl chloride (0.042 mL, 0.37 mmol). The reaction was stirred at room temperature for 1 hour, quenched with saturated sodium bicarbonate solution and extracted with ethyl acetate. The combined extracts were dried over MgSO4 and concentrated to dryness under reduced pressure. The resulting residue was treated with 1.0 M potassium tert-butoxide in tetrahydrofuran (0.84 mL, 0.84 mmol) in tetrahydrofuran (2 mL) at room temperature for 2 hours. The reaction was quenched with aq. NH4Cl, extracted with ethyl acetate. The combined organic layers were washed with water and brine, dried over MgSO4 and evaporated. The residue was purified on silica gel (eluting with 0-40% of ethyl acetate in hexanes) to give the desired product (15 mg, 12%), LCMS calculated for C19H17ClF2NO2 (M+H)+: m/z=364.1. found: 364.1.
