反应详情

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 1,4-dioxane (100 mL), 1-methyl-1H-pyrazol-3-amine (970 mg, 10.0 mmol), 3,5-dibromo-1-methylpyridin-2-(1H)-one (2.9 g, 11 mmol), and cesium carbonate (6.5 g, 20.0 mmol). After bubbling nitrogen through the suspension for 10 minutes, tris(dibenzylideneacetone)dipalladium(0) (457 mg, 0.50 mmol) and Xantphos (587 mg, 1.0 mmol) were added. The system was subjected to three cycles of vacuum/argon flush and heated at reflux for 2 h. It was then cooled to room temperature and filtered. The solid was washed with dichloromethane (2×50 mL) and the combined organic filtrate was concentrated. The residue was purified by silica-gel column chromatography eluting with 30:1 dichloromethane/methanol to afford 140a as a yellow solid (900 mg, 32%). MS-ESI: [M+H]+ 283.1

1. customA 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser
2. customAfter bubbling nitrogen through the suspension for 10 minutes
3. customflush
4. temperatureheated
5. temperatureat reflux for 2 h
6. filtrationfiltered
7. washThe solid was washed with dichloromethane (2×50 mL)
8. concentrationthe combined organic filtrate was concentrated
9. customThe residue was purified by silica-gel column chromatography
10. washeluting with 30:1 dichloromethane/methanol