Trimethyl borate → (2-Methoxy-4-methylphenyl)boronic acid

Temperature

-78 °C

To a cooled (−78° C.) solution of 1-bromo-2-methoxy-4-methylbenzene (0.5 g; 2.49 mmol) in dry THF (12.5 mL) under argon atmosphere was added dropwise a tert-butyllithium solution (1.6M in pentane) (3.65 mL; 5.47 mmol). After 10 min, trimethyl borate (0.424 mL; 3.73 mmol) was added dropwise as a neat liquid and the reaction was stirred at −78° C. for 1 h. The reaction was allowed to warm up to room temperature and was stirred for another 1 h. The mixture was quenched with a saturated solution of ammonium chloride and the mixture was concentrated under reduced pressure. The residue was acidified with a solution of hydrochloric acid 2N and the mixture was extracted with dichloromethane. The organic layer was washed with brine, dried over magnesium sulphate and concentrated under reduced pressure. The crude product was precipitated out off a mixture of dichloromethane-heptane, filtered, washed with heptane and dried under reduced pressure to afford 0.095 g (23%) of the title compound as an off-white solid.

1. temperatureto warm up to room temperature
2. stirringwas stirred for another 1 h
3. customThe mixture was quenched with a saturated solution of ammonium chloride
4. concentrationthe mixture was concentrated under reduced pressure
5. extractionthe mixture was extracted with dichloromethane
6. washThe organic layer was washed with brine
7. dry with materialdried over magnesium sulphate
8. concentrationconcentrated under reduced pressure
9. customThe crude product was precipitated out off
10. additiona mixture of dichloromethane-heptane
11. filtrationfiltered
12. washwashed with heptane
13. customdried under reduced pressure

ORD record

ord-ffbffd7ed17947c3956f3545a67a0fa0

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08906906B2