To a suspension of 1-[7-chloro-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridin-3-yl]-2-propyn-1-one (36 mg, 0.12 mmol) and benzamidine hydrochloride (25 mg, 0.16 mmol) in ethanol (500 μL) was added sodium ethoxide (52 μL, 3 M in ethanol, 0.16 mmol). The reaction mixture was stirred at room temperature 16 hours. The reaction mixture was diluted with water and extracted with ethyl acetate. The organic layer was washed with water and brine, then dried over magnesium sulfate. Filtration and concentration, followed by flash chromatography (3:1 hexanes-ethyl acetate) provided 7-chloro-2-(4-fluorophenyl)-3-(2-phenylpyrimidin-4-yl)pyrazolo[1,5-α]pyridine (34 mg, 71%). Rf 0.36 (3:1 hexanes-ethyl acetate); 1H NMR (CDCl3) δ 8.60–8.56 (m, 2H), 8.52–8.48 (m, 2H), 7.67 (m, 2H), 7.56–7.52 (m, 3H), 7.39 (m, 1H), 7.22–7.11 (m, 3H), 6.93 (d, 1H); 19F NMR (CDCl3) δ −112.30; MS m/z 401 (M+1).
