Reaction #502135

Reaction equation

hydrochloric acid

triisopropyl borate

n-butyllithium

5-bromo-2-methoxypyridine

→

6-Methoxypyridin-3-ylboronic acid

Solvents

diethyl ether

hexane

Water

tetrahydrofuran

Conditions

Workup

1. 1
   Otherresults in a yellow solution which
2. 2
   workup.STIRRINGby stirring for a further hour, during which the solution
3. 3
   Otherwarms to −20° C
4. 4
   workup.STIRRINGthe mixture is stirred overnight
5. 5
   Extractionextracted twice with ethyl acetate
6. 6
   DryingThe organic phase is dried over sodium sulphate
7. 7
   Filtrationfiltered
8. 8
   Concentrationconcentrated
9. 9
   Otherresulting in a pale brown solid which
10. 10
    Filtrationfiltered
11. 11
    Other0.38 g (47% of theory) of the product is isolated

Procedure

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.

Source