反应详情

A mixture of (1-methyl-1H-pyrazol-5-yl)boronic acid (C1) (60.0 g, 0.476 mol) and 1-bromo-4-methylbenzene (75.0 g, 0.438 mol) in a mixture of 1,2-dimethoxyethane (1.2 L) and 2 M aqueous sodium carbonate solution (550 mL) was degassed and purged with N2; this procedure was then repeated twice. Dichlorobis(triphenylphosphine)palladium(II) (3.1 g, 4.4 mmol) was added and the mixture was purged twice with N2. The reaction mixture was heated to reflux and stirred under N2 for 3 hours. The mixture was cooled and 1,2-dimethoxyethane was removed under reduced pressure; water (500 mL) was added to the residue, and the resulting mixture was extracted with dichloromethane (3×500 mL). The combined organic layers were washed with saturated aqueous sodium chloride solution, dried over sodium sulfate, filtered, and concentrated in vacuo. Purification via silica gel chromatography (Eluent: 100:1 petroleum ether/ethyl acetate) provided the product as a yellow liquid. Yield: 55.0 g, 319 mmol, 73%. 1H NMR (400 MHz, CDCl3) δ 2.42 (s, 3H), 3.89 (s, 3H), 6.29 (d, J=1.8 Hz, 1H), 7.29 (br AB quartet, JAB=8 Hz, ΔνAB=18 Hz, 4H), 7.52 (d, J=2.0 Hz, 1H).

1. customwas degassed
2. custompurged with N2
3. customthe mixture was purged twice with N2
4. temperatureThe reaction mixture was heated
5. temperatureto reflux
6. temperatureThe mixture was cooled
7. custom1,2-dimethoxyethane was removed under reduced pressure
8. additionwater (500 mL) was added to the residue
9. extractionthe resulting mixture was extracted with dichloromethane (3×500 mL)
10. washThe combined organic layers were washed with saturated aqueous sodium chloride solution
11. dry with materialdried over sodium sulfate
12. filtrationfiltered
13. concentrationconcentrated in vacuo
14. customPurification via silica gel chromatography (Eluent: 100:1 petroleum ether/ethyl acetate)