反应详情

温度

-78 °C

An 250 mL round-bottom flask was charged with 5-(2-bromo-5-(trifluoromethyl)phenyl)-1-methyl-1H-pyrazole (Intermediate F) (2.956 g, 9.69 mmol), diethyl ether (74.5 mL), and triisopropyl borate (2.70 mL, 11.63 mmol). The flask was cooled to −78° C. for 10 min, after which butyllithium (2.5M in hexanes) (4.65 mL, 11.63 mmol) was added dropwise. The mixture was stirred for 30 min, and then warmed to room temperature. A 2N aq. NaOH solution (100 mL) was added, and the resulting biphasic mixture was stirred vigorously for 1 h. The mixture was diluted with water, and the layers separated. The ethereal layer was extracted with water (twice) and the water layers were combined and washed with diethyl ether. The ether layers were back-extracted once more, and all aqueous layers combined and acidified to a pH of about 2 with 6N aq. HCl to give a clear solution. The aqueous layer was extracted with ethyl acetate (twice), and the combined organics were dried over sodium sulfate, filtered and concentrated. The residue was concentrated from DCM to give (2-(1-methyl-1H-pyrazol-5-yl)-4-(trifluoromethyl)phenyl)boronic acid (2.36 g, 8.74 mmol) as a yellow solid. m/z (ESI) 271.2 (M+H)+.

1. temperaturewarmed to room temperature
2. stirringthe resulting biphasic mixture was stirred vigorously for 1 h
3. customthe layers separated
4. extractionThe ethereal layer was extracted with water (twice) and the water layers
5. washwashed with diethyl ether
6. extractionThe ether layers were back-extracted once more
7. customto give a clear solution
8. extractionThe aqueous layer was extracted with ethyl acetate (twice), and the combined
9. dry with materialorganics were dried over sodium sulfate
10. filtrationfiltered
11. concentrationconcentrated
12. concentrationThe residue was concentrated from DCM