Boron tribromide → 1-(1-Benzofuran-3-yl)ethan-1-one

Temperature

0 °C

A solution of 2-methoxyphenylacetone (5 g, 30.5 mmol) in N,N-dimethylformamide dimethyl acetal (8.7 ml, 73.1 mmol) was stirred at 80° C. for 4 hours. The mixture was concentrated under vacuum. The resulting residue was dissolved in dichloromethane (40 ml), cooled to 0° C. and treated with a solution of boron tribromide (5 ml, 52.9 mmol) in dichloromethane (10 ml). After stirring at 0° C. for 1 hour, additional boron tribromide (5 ml, 52.9 mmol) was added. The mixture was stirred at 0° C. for 10 more minutes and was poured into a mixture of ice and saturated aqueous sodium bicarbonate. The resulting mixture was extracted with dichloromethane three times. The combined organic extracts were washed with water once and dried over anhydrous sodium sulfate to give 3-acetylbenzofuran (4.7 g, 96%, 94.5% AUC HPLC): 1H NMR (300 MHz, CDCl3) δ 8.16-8.19 (m, 2H), 7.44-7.48 (m, 1H), 7.29-7.32 (m, 2 H), 2.50 (s, 3H).

1. concentrationThe mixture was concentrated under vacuum
2. dissolutionThe resulting residue was dissolved in dichloromethane (40 ml)
3. stirringThe mixture was stirred at 0° C. for 10 more minutes
4. extractionThe resulting mixture was extracted with dichloromethane three times
5. washThe combined organic extracts were washed with water once
6. dry with materialdried over anhydrous sodium sulfate

ORD record

ord-ca046b20f56f4475ba1408cace02e7a3

Source dataset

uspto-grants-2009_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07541357B2