Cesium carbonate → HCID 58044266, compound

Participants

Reaction Steps

A 250-mL three-neck round-bottomed flask equipped with a reflux condenser, magnetic stirrer and nitrogen inlet was charged with 123b (444 mg, 3.61 mmol), 2,5-dibromo-1-methylpyrazin-6-one (1.06 g, 3.97 mmol), cesium carbonate (3.52 g, 10.8 mmol), and 1,4-dioxane (45 mL). After bubbling nitrogen through the resulting suspension for 30 min, Xantphos (177 mg, 0.306 mmol) and tris(dibenzylideneacetone)-dipalladium(0) (165 mg, 0.180 mmol) were added, and the reaction mixture was heated at reflux for 3 h. After this time, the mixture was cooled to room temperature and diluted with ethyl acetate (150 mL) and water (30 mL). The organic layer was separated, and the aqueous layer was extracted with ethyl acetate (3×150 mL). The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure. The residue was triturated with methanol (20 mL) to afford a 63% yield (700 mg) of 123c as an off-white solid: mp 161-163° C.; 1H NMR (300 MHz, DMSO-d6) d 8.42 (s, 1H), 8.00 (d, 1H, J=2.5 Hz), 7.57 (d, 1H, J=2.4 Hz), 7.38 (d, 1H, J=2.5 Hz), 6.05 (d, 1H, J=2.4 Hz), 3.61 (m, 1H), 3.49 (s, 1H), 0.95 (m, 4H); MS (ESI+) m/z 309.0 (M+H).

Provenance & Evidence