A glass microwave reaction vessel was charged with 3-bromo-5-chloro-N-(6-methoxypyridin-3-yl)pyrazin-2-amine (83 mg, 0.263 mmol), copper (I) iodide (10 mg, 0.053 mmol, Aldrich), cesium fluoride (80 mg, 0.526 mmol, Alfa Aesar), tetrakis(triphenylphosphine)palladium(0) (30.4 mg, 0.026 mmol) and 2-methyl-4-(methylthio)-6-(tributylstannyl)pyrimidine (113 mg, 0.263 mmol) in dioxane (2 mL). The reaction mixture was stirred and heated in a Emrys Optimizer microwave reactor (Personal Chemistry, Biotage AB, Inc., Upssala, Sweden) at 140° C. for 30 min. The reaction mixture was diluted with water (10 mL) and extracted with CH2Cl2 (2×30 mL). The combined organic extracts were washed with saturated NaCl (10 mL) and dried over Na2SO4. The solution was filtered and concentrated in vacuo to give the crude material as a yellow solid. The crude product was purified by silica gel chromatography eluting with 10% EtOAc/hexanes to give 5-chloro-N-(6-methoxypyridin-3-yl)-3-(2-methyl-6-(methylthio)pyrimidin-4-yl)pyrazin-2-amine (72 mg, 0.192 mmol, 73.0% yield). 1H NMR (300 MHz, CDCl3) δ 2.63 (s, 3H) 2.78 (s, 3H) 3.95 (s, 3H) 6.79 (d, J=8.77 Hz, 1H) 8.01 (dd, J=8.70, 2.12 Hz, 1H) 8.17 (d, J=5.55 Hz, 2H) 8.39 (s, 1H) 12.21 (s, 1H). m/z (ESI, +ve ion) 375.0 (M+H)+.
