Hydrochloric Acid → (6-Methoxypyridin-3-yl)boronic acid

Temperature

-78 °C

1 g (5.32 mmol) of 5-bromo-2-methoxypyridine is dissolved in 10 ml of absolute tetrahydrofuran and cooled to −78° C. Addition of 0.4 g (6.38 mmol) of a 1.6 M n-butyllithium solution in hexane results in a yellow solution which is stirred at the given temperature for 30 min. Addition of 3 g (15.9 mmol) of triisopropyl borate is followed by stirring for a further hour, during which the solution warms to −20° C. Water is added, and the mixture is stirred overnight. The crude solution is acidified to pH 5 with 1 N hydrochloric acid and extracted twice with ethyl acetate. The organic phase is dried over sodium sulphate, filtered and concentrated, resulting in a pale brown solid which is suspended in diethyl ether and filtered. 0.38 g (47% of theory) of the product is isolated.

1. customresults in a yellow solution which
2. stirringby stirring for a further hour, during which the solution
3. customwarms to −20° C
4. stirringthe mixture is stirred overnight
5. extractionextracted twice with ethyl acetate
6. dry with materialThe organic phase is dried over sodium sulphate
7. filtrationfiltered
8. concentrationconcentrated
9. customresulting in a pale brown solid which
10. filtrationfiltered
11. custom0.38 g (47% of theory) of the product is isolated

ORD record

ord-ad78ec2c0efa4d80aa9b82a4ce378deb

Source dataset

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08088769B2