反应详情

温度

0 °C

Magnesium (9.52 g) was suspended in 119 mL of tetrahydrofuran, and to the suspension were added 3.00 g of 2-bromothioanisole and about 20 mg of iodine. After the reaction was started by heating employing a dryer, 72 g of 2-bromothioanisole was dropped to the mixture during 20 minutes. After being heated for 1 hour, the reaction mixture was diluted with 1000 mL of tetrahydrofuran, and cooled to 0° C. To the mixture was added 102 mL of triisopropyl borate at the same temperature, and the mixture was stirred at room temperature for 4 hours. To the reaction mixture was added water, and the solvent was removed under reduced pressure. The residue was added 500 mL of 2 mol/L hydrochloric acid, and the mixture was extracted with 300 mL of diethyl ether. The organic layer was extracted with 500 mL of 2 mol/L aqueous sodium hydroxide solution, and the aqueous layer was acidified by addition of concentrated hydrochloric acid under ice-cooling. The residual diethyl ether was removed under reduced pressure, and the precipitate was collected by filtration to give 45.95 g of 2-(methylthio)phenylboronic acid.

1. temperatureby heating
2. additionwas dropped to the mixture during 20 minutes
3. temperatureAfter being heated for 1 hour
4. customthe solvent was removed under reduced pressure
5. additionThe residue was added 500 mL of 2 mol/L hydrochloric acid
6. extractionthe mixture was extracted with 300 mL of diethyl ether
7. extractionThe organic layer was extracted with 500 mL of 2 mol/L aqueous sodium hydroxide solution
8. additionthe aqueous layer was acidified by addition of concentrated hydrochloric acid under ice-
9. temperaturecooling
10. customThe residual diethyl ether was removed under reduced pressure
11. filtrationthe precipitate was collected by filtration