A mixture of 4-(6-bromo-4-methyl-3-oxo-3,4-dihydro-pyrazin-2-ylamino)-benzoic acid ethyl ester (2) (340 mg; 0.97 mmol), 4-tert-butyl-N-[2-methyl-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-benzamide (5) (457 mg; 1.16 mmol), tetrakis(triphenylphosphine)palladium (56 mg; 0.05 mmol), 1N sodium carbonate (2.9 mL; 2.9 mmol), and 1,2-dimethoxyethane (30 mL) was heated at 100 degrees in a sealed pressure vessel for 16 hr. The mixture was cooled to room temperature, treated with water (70 mL) and extracted with ethyl acetate (3×60 mL). The combined organic extracts were washed with water (2×40 mL) and brine (1×40 mL), dried over magnesium sulfate, and evaporated under reduced pressure. The resulting residue was triturated with diethyl ether/dichloromethane to give 4-{6-[3-(4-tert-butyl-benzoylamino)-2-methyl-phenyl]-4-methyl-3-oxo-3,4-dihydro-pyrazin-2-ylamino}-benzoic acid ethyl ester (6) as a gray solid (330 mg), MS 539.49 (M+H).
