反应详情

A 50-mL three-neck round-bottomed flask equipped with a magnetic stirrer, reflux condenser and nitrogen inlet was charged with 1,4-dioxane (20 mL), 131b (600 mg, 4.31 mmol), 3,5-dibromo-1-methylpyridine-2(1H)-one (1.44 g, 5.40 mmol) and cesium carbonate (3.08 g, 9.48 mmol). After bubbling nitrogen through the resulting solution for 30 min, Xantphos (300 mg, 0.52 mmol) and tris(dibenzylideneacetone)dipalladium(0) (320 mg, 0.35 mmol) were added, and the reaction mixture was heated at reflux for 2 h. After this time the reaction was cooled to room temperature, partitioned between ethyl acetate (75 mL) and water (75 mL) and filtered. The aqueous layer was separated and extracted with ethyl acetate (2×25 mL). The organic layers were combined and washed with brine (50 mL) and dried over sodium sulfate. The drying agent was removed by filtration and the filtrate concentrated under reduced pressure. The resulting residue was purified by column chromatography using 500 cc of silica gel and eluting with 1% methanol in methylene chloride. The fractions were collected to afford, after concentrating under reduced pressure, a 31% yield (433 mg) of 131c as a green solid: mp 195-197° C.; 1H NMR (300 MHz, CDCl3) 7.92 (d, 1H, J=2.4 Hz), 7.44 (s, 1H), 6.90 (d, 1H, J=2.4 Hz), 5.65 (s, 1H), 4.80 (s, 2H), 4.13 (s, 2H), 3.61 (s, 5H); MS (ESI+) m/z 324.9 (M+H).

1. customA 50-mL three-neck round-bottomed flask equipped with a magnetic stirrer
2. temperaturereflux condenser and nitrogen inlet
3. customAfter bubbling nitrogen through the resulting solution for 30 min
4. temperaturethe reaction mixture was heated
5. temperatureat reflux for 2 h
6. custompartitioned between ethyl acetate (75 mL) and water (75 mL)
7. filtrationfiltered
8. customThe aqueous layer was separated
9. extractionextracted with ethyl acetate (2×25 mL)
10. washwashed with brine (50 mL)
11. dry with materialdried over sodium sulfate
12. customThe drying agent was removed by filtration
13. concentrationthe filtrate concentrated under reduced pressure
14. customThe resulting residue was purified by column chromatography
15. washeluting with 1% methanol in methylene chloride
16. customThe fractions were collected
17. customto afford
18. concentrationafter concentrating under reduced pressure