To a stirring solution of 5-bromo-1-tert-butyl-3-cyclobutyl-1,7-dihydro -pyrazolo[3,4-b]pyridin-6-one (50.0 mg, 0.15 mmol) in dimethoxyethane (1.5 mL) was added 3,5-dichlorophenyl-boronic acid (32.6 mg, 0.17 mmol), followed by cesium fluoride (51.9 mg, 0.34 mmol), and Pd(PPh3)4 (catalytic amount, 0.005 mmol). The reaction mixture was heated to reflux. After 3 hr, additional amounts of 3,5-dichlorophenyl-boronic acid (32.6 mg, 0.17 mmol), cesium fluoride (51.9 mg, 0.34 mmol), and Pd(PPh3)4 (catalytic amount, 0.005 mmol) were added. After a total of 18 hr, the reaction was cooled to room temperature, diluted with CH2Cl2 and washed with water. The organic layer was dried over MgSO4, filtered through a fritted funnel, and concentrated under reduced pressure. Purification of the resulting material was accomplished by flash chromatography with a Biotage® column, eluting with 5% EtOAc/toluene. The product-containing fractions were collected and concentrated to give the title compound (7.0 mg, 12% yield). LRMS m/z (APCl) 390. 392(M+1).
