A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 5-methylisoxazol-3-amine (1.0 g, 10.2 mmol), 3,5-dibromo-1-methylpyridin-2(1H)-one (4.09 g, 15.3 mmol), Pd2(dba)3 (467 mg, 0.51 mmol), Xantphos (598 mg, 1.02 mmol), Cs2CO3 (6.65 g, 20.4 mmol), and dioxane (50 mL). After three cycles of vacuum/argon flush, the reaction mixture was heated at 100° C. for 3 h. Analysis of the reaction mixture by LCMS showed complete conversion to the desired product. It was filtered when the mixture was still hot. The filtrate was cooled down to room temperature and the resulting precipitation was collected by filtration to afford 283a (1.6 g, 55%) as a yellow solid. MS-ESI: [M+H]+ 284.1
