Trimethylboroxine (0.348 mL, 2.5 mmol) was added to a suspension of 7-bromo-2-(2,6-dichlorophenyl)-2H-pyrazolo[4,3-c]pyridine-5-oxide (720 mg, 2.0 mmol), potassium carbonate (829 mg, 6.0 mmol) and Pd(PPh3)4 (228 mg, 0.2 mmol) in dioxane (11 mL) and the reaction mixture was heated at 80° C., under an atmosphere of nitrogen overnight. Additional trimethylboroxine (0.278 mL) was added and the reaction mixture was heated at 80° C. for another 2 hours. The resultant mixture was cooled to room temperature and filtered. The solid was washed with ethyl acetate and methanol (9:1). The filtrate was concentrated under reduced pressure to give a brown solid. This was purified by silica gel flash chromatography (0-20% methanol in ethyl acetate) to afford the title compound as a pale yellow solid (405 mg, 69% yield). LCMS (Method F): RT=2.30 min, m/z: 294 [M+H+].
