反应详情

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 1,4-dioxane (50 mL), 248a (330 mg, 1.5 mmol), 4-bromo-6-chloro-2-methylpyridazin-3(2H)-one (446 mg, 2.0 mmol), cesium carbonate (978 mg, 3.0 mmol), Xantphos (88 mg, 0.15 mmol), and tris(dibenzylideneacetone)dipalladium(0) (68 mg, 0.075 mmol). The system was subjected to three cycles of vacuum/argon flush and heated at reflux for 4 h. It was then cooled to room temperature and filtered. The solid was washed with dichloromethane (3×30 mL) and the combined filtrate was concentrated under reduced pressure. The residue was purified by silica-gel column chromatography eluting with petroleum ether/ethyl acetate (2:1 to 1:2) to afford 248b (430 mg, 79%) as yellow solid. MS-ESI: [M+H]+ 364.3

1. customA 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser
2. customflush
3. temperatureheated
4. temperatureat reflux for 4 h
5. filtrationfiltered
6. washThe solid was washed with dichloromethane (3×30 mL)
7. concentrationthe combined filtrate was concentrated under reduced pressure
8. customThe residue was purified by silica-gel column chromatography
9. washeluting with petroleum ether/ethyl acetate (2:1 to 1:2)