A mixture of (1-(tert-butoxycarbonyl)-4-fluoro-1H-indol-2-yl)boronic acid (5 g, 18.0 mmol), 6-chloro-2-iodopyridin-3-ol (3.82 g, 15.0 mol) and NaHCO3 (3.78 g, 45.0 mol) in 1,4-dioxane (76 mL) and water (7 mL) was stirred at room temperature for 15 minutes. Then Pd(PPh3)2Cl2 (527 mg, 0.75 mmol) was added under nitrogen atmosphere, and the mixture was heated at 100° C. under N2 for 16 hours. The reaction mixture was cooled to room temperature, diluted with EtOAc (50 mL), filtered and concentrated in vacuo. The resulting residue was diluted with H2O (60 mL) and EtOAc (30 mL), and the layer was separated, the aqueous layer was extracted with EtOAc (3*30 mL). The combined organic layers were washed with brine (50 mL), dried over Na2SO4, filtered and concentrated in vacuo. The resulting residue was purified using column chromatography (petroleum ether/EtOAc=20/1˜3/1) to provide 6-chloro-2-(4-fluoro-1H-indol-2-yl)pyridin-3-ol (3 g, yield: 76.5%). 1H-NMR (MeOD, 400 MHz) δ 7.36 (s, 1H), 7.23˜7.27 (m, 2H), 7.03˜7.11 (m, 2H), 6.63˜6.68 (m, 1H). MS (M+H)+: 263/265.
