2,2-Dimethyl-propionic acid 5-bromo-3-iodo-pyrazolo[3,4-b]pyridin-1-ylmethyl ester (1.46 g, 3.33 mmol), 3-chlorobenzylzinc chloride (0.5 M in tetrahydrofuran, 6.8 ml, 3.40 mmol), tetrakis(triphenylphosphino)palladium(0) (384 mg, 0.33 mmol), and tetrahydro-furan (10 ml) were combined and stirred for 18 hours at 50° C. The reaction was quenched with saturated, aqueous ammonium chloride, and extracted with dichloromethane. The organic layer was dried over sodium sulfate and concentrated in vacuo. The crude material was purified by flash chromatography (0 to 10% ethyl acetate in hexanes) to give 436 mg (30%) of 2,2-dimethyl-propionic acid 5-bromo-3-(3-chloro-benzyl)-pyrazolo[3,4-b]pyridin-1-ylmethyl ester. 1H-NMR (250 MHz, DMSO-d6) δ 8.56 (s, 1H), 7.88 (s, 1H), 7.24-7.18 (m, 4H), 6.41 (s, 2H), 4.25 (s, 2H), 1.18 (s, 9H); MS: m/z 436.1, 438.1 (M+H+).
