Cesium carbonate → 5-Bromo-3-(4-(1,4-dimethyl-3-oxopiperazin-2-yl)phenylamino)-1-methylpyrazin-2(1H)-one

Participants

Reaction Steps

A 100-mL three-neck round-bottomed flask equipped with a mechanical stirrer and reflux condenser was charged with (4) (780 mg, 3.56 mmol), 13 (998 mg, 3.73 mmol), cesium carbonate (2.36 g, 7.26 mmol) and 1,4-dioxane (40 mL). After bubbling nitrogen through the resulting solution for 30 minutes, Xantphos (0.162 g, 0.281 mmol) and tris(dibenzylideneacetone)dipalladium(0) (0.15 g, 0.165 mmol) were added, and the reaction mixture was heated at reflux for 16 h. After this time the reaction was cooled to room temperature and concentrated under reduced pressure. The resulting residue was absorbed onto silica gel and purified by flash chromatography to afford a 57% yield (818 mg) of 14 as an orange solid: mp 206-207° C.; 1H NMR (500 MHz, CDCl3) δ 8.27 (bs, 1H), 7.72 (dd, 1H, J=2.0, 8.5 Hz), 7.36 (dd, 2H, J=2.0, 8.5 Hz), 6.73 (s, 1H), 3.71 (m, 1H), 3.69 (s, 1H), 3.52 (s, 3H), 3.21 (m, 1H), 3.01 (m, 1H), 2.97 (s, 3H), 2.67 (m, 1H), 2.19 (s, 3H); MS (ESI+) m/z 406 (M+H).

Provenance & Evidence