Hydrochloric Acid → (5-Fluoro-1-benzofuran-2-yl)boronic acid

Temperature

0 °C

In a nitrogen atmosphere, to a solution of 2.0 g of 5-fluorobenzofuran in 150 ml tetrahydrofuran was added 18.5 ml of a 1.59 M solution of n-butyllithium in n-hexane at −78° C., and the mixture was stirred at the same temperature for 10 minutes and at 0° C. for further 10 minutes. At −78° C., 3.7 ml of triethoxyborane was added, and the mixture was stirred for 2 hours while elevating to 0° C. 30 ml of 1 N hydrochloric acid was added, stirred at room temperature for 1 hour, and then the mixture was extracted with ethyl acetate. The extract was washed with brine, dried over anhydrous magnesium sulfate and the solvent was evaporated. The crude product was purified and separated by silica gel column chromatography (ethyl acetate:n-hexane=1:3 to 1:1), to give 525 mg of the title compound as colorless crystals.

1. stirringthe mixture was stirred for 2 hours
2. customwhile elevating to 0° C
3. stirringstirred at room temperature for 1 hour
4. extractionthe mixture was extracted with ethyl acetate
5. washThe extract was washed with brine
6. dry with materialdried over anhydrous magnesium sulfate
7. customthe solvent was evaporated
8. customThe crude product was purified
9. customseparated by silica gel column chromatography (ethyl acetate:n-hexane=1:3 to 1:1)

ORD record

ord-148221a39520470fbc441108e1d2406d

Source dataset

uspto-grants-2009_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07541376B2