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 completed conversion to the desired product. It was filtered when the mixture was still hot. The filtrate was cooled to room temperature and the resulting precipitate was collected by filtration to afford 129a (1.6 g, 55%) as a yellow solid. MS-ESI: [M+H]+ 284.1
