In an adaption of GP 3c, 640 mg of 4-bromo-1-methyl-1H-pyrazolo[3,4-c]pyridine (Intermediate 2.1, 3 mmol, 1 eq), 1000 mg 3-trimethylsilanylethynyl-phenylamine (4.92 mmol, 1.63 eq.), 106 mg dichlorobis(triphenylphosphine)palladium (II) (PdCl2(PPh3)2) (0.15 mmol, 5 mol %) and 115 mg copper (I) iodide (0.6 mmol, 0.2 eq.) were dissolved in 15 mL THF (0.2 M) and treated with 3.6 mL tetra-n-butylammonium fluoride solution (1.0 M in THF, 3.6 mmol, 1.2 eq.). The resulting mixture was heated to 80° C. in a Biotage Initiator microwave oven for 30 min. Extractive work-up followed by column chromatography provided the 460 mg of the target compound (58% yield).
