反应详情

To a solution of 2,6-Dichloro-3-fluorobenzoic acid (125 g, 0.59 mol) in THF (200 mL) was added BH3.THF (592 mL, 592 mmol, 1M solution in THF) dropwise at room temperature. The reaction mixture was heated to reflux for 12 h. The borane was quenched with methanol (200 mL) and the resulting solution was concentrated to dryness. The residue was again co-evaporated with methanol to remove most of the trimethylborate. To the residue was added aq. sodium carbonate (50 g in 500 mL). The mixture was cooled and a white fine precipitate was filtered off to give the title compound. 1H NMR (CDCl3, 300 MHz): δ=2.10 (t, 1H, J=6.9 Hz), 4.96 (d, 2H, J=6.9 Hz), 7.09 (dd, 1H, J=8.1, 9.0 Hz), 7.29 (dd, 1H, J=4.8, 9.0 Hz).

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 12 h
3. customThe borane was quenched with methanol (200 mL)
4. concentrationthe resulting solution was concentrated to dryness
5. customto remove most of the trimethylborate
6. additionTo the residue was added aq. sodium carbonate (50 g in 500 mL)
7. temperatureThe mixture was cooled
8. filtrationa white fine precipitate was filtered off