Hydrochloric Acid → 2-Methoxy-5-(trifluoromethoxy)phenylboronic acid

Temperature

-78 °C

n-Butyllithium (1.6M in hexanes, 3.8 mL, 6 mmol) was added dropwise to a cooled (−78° C.) solution of 2-bromo-1-methoxy-4-(trifluoromethoxy)benzene (Description 16, 1.5 g, 5.5 mmol) in tetrahydrofuran (prefiltered through alumina, 18 mL) [internal temperature <−70° C.]. The mixture was stirred at −78° C. for 15 min., then trimethylborate (2 mL, 17.6 mmol) was added dropwise [internal temperature <−70° C.]. The mixture was stirred at −78° C. for 30 min., then hydrochloric acid (1M, 6 mL) was added. The mixture was warmed to room temperature and stirred for 30 min. Water (25 mL) was added and the mixture was extracted with ethyl acetate (2×40 mL). The combined organic fractions were washed with water (20 mL) and brine (20 mL), dried (MgSO4) and the solvent was evaporated under reduced pressure. The residue was triturated with hexane and the solid was collected and dried in vacuo at 40° C. to give the title compound as an off white solid (366 mg, 28%). 1H NMR (360 MHz, CDCl3) δ3.93 (3H, s), 5.84 (2H, s), 6.90 (1H, d, J 9.0 Hz), 7.29 (1H, m) and 7.70 (1H, J 2.6 Hz).

1. stirringThe mixture was stirred at −78° C. for 30 min.
2. temperatureThe mixture was warmed to room temperature
3. stirringstirred for 30 min
4. extractionthe mixture was extracted with ethyl acetate (2×40 mL)
5. washThe combined organic fractions were washed with water (20 mL) and brine (20 mL)
6. dry with materialdried (MgSO4)
7. customthe solvent was evaporated under reduced pressure
8. customThe residue was triturated with hexane
9. customthe solid was collected
10. customdried in vacuo at 40° C.

ORD record

ord-fcc6edc6715a45b49426e8c5cc966f69

Source dataset

uspto-grants-2003_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06518273B1