Acetic Acid → 3-Bromodibenzofuran

Temperature

0 °C

NaNO2 (2.21 g, 32.05 mmol) was dissolved in 20 mL conc. H2SO4 in conical flask kept at 0° C. Solution of 2-aminodibenzofuran (5.3 g, 28.9 mmol) in minimum volume of glacial acetic acid was then slowly added to the flask so that temperature never raised above 5-8° C. and the mixture was stirred at 0° C. for another 1.5 h. 100 mL ether was added to the stirred mixture and precipitate of corresponding diazo salt immediately settled down. Brown color diazo salt was immediately filtered out and transferred to a flask containing CuBr (6.25 g, 43.5 mmol) in 150 mL 48% HBr. The flask was then placed in a water bath maintained at 64° C. and stirred for 2 h. After cooling down to room temperature, the dark color reaction content was filtered out and the precipitate was washed with water twice. Isolated solid was then flashed over Silica gel column with 5-10% DCM/Hexane to give 4.79 g final compound.

1. customkept at 0° C
2. filtrationBrown color diazo salt was immediately filtered out
3. customtransferred to a flask
4. customThe flask was then placed in a water bath
5. temperaturemaintained at 64° C.
6. stirringstirred for 2 h
7. temperatureAfter cooling down to room temperature
8. customthe dark color reaction content
9. filtrationwas filtered out
10. washthe precipitate was washed with water twice
11. customIsolated solid

ORD record

ord-3b9d2d8181fb4f66a0906c8428c6653c

Source dataset

uspto-grants-2014_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08722205B2