Water → 5-Bromo-2-methyl-1-benzofuran

Temperature

-70 °C

(5-Bromo-2-methoxyphenyl)acetone (6.6 g, 28.6 mmol) was dissolved in methylene chloride (50 ml) and cooled to −70° C. Thereto was dropwise added a 1 M solution (28.6 ml, 28.6 mmol) of boron tribromide in methylene chloride over 15 min. After the dropwise addition, the mixture was heated to room temperature and stirred for 1.5 hr. Then, the reaction mixture was ice-cooled and water (50 ml) was added. The insoluble matter was filtered off and the filtrate was partitioned. The aqueous layer was extracted with methylene chloride. The organic layers were combined, and dried over anhydrous sodium sulfate. The desiccant was filtered off and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=30/1) to give the objective compound (3.45 g, 57%) as a colorless liquid.

1. additionAfter the dropwise addition
2. temperaturethe mixture was heated to room temperature
3. temperaturecooled
4. filtrationThe insoluble matter was filtered off
5. customthe filtrate was partitioned
6. extractionThe aqueous layer was extracted with methylene chloride
7. dry with materialdried over anhydrous sodium sulfate
8. filtrationThe desiccant was filtered off
9. concentrationthe filtrate was concentrated under reduced pressure
10. customThe residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=30/1)

ORD record

ord-a2727a53f3b5433eb1d61288f276167b

Source dataset

uspto-grants-2005_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06911469B2