Diethyl Ether → 7-Bromo-1-benzofuran

A stirred mixture of polyphosphoric acid (˜5 g) and chlorobenzene (8 mL) was heated at reflux and a solution of 1-(2,2-diethoxyethoxy)-2-bromobenzene (2.62 g, 9.0 mmol) in chlorobenzene (3 mL) was added dropwise over 10 min. The mixture was heated at reflux for 1.5 h. The mixture was allowed to cool to rt and 1 M aq NaOH (20 mL) was added, followed by ether (175 mL). The mixture was washed with water (2×20 mL) and brine (20 mL), and dried over MgSO4. Evaporation of the solvent left a residue which was purified by a chromatography on a 140-g silica cartridge eluted with hexanes and a 0-10% EtOAc in hexanes gradient. Appropriate fractions were pooled and concentrated to afford 7-bromobenzofuran (0.65 g, 38% from 2-bromophenol) as a clear colorless oil.

1. temperaturewas heated
2. temperatureat reflux
3. temperatureThe mixture was heated
4. temperatureat reflux for 1.5 h
5. washThe mixture was washed with water (2×20 mL) and brine (20 mL)
6. dry with materialdried over MgSO4
7. customEvaporation of the solvent
8. waitleft a residue which
9. customwas purified by a chromatography on a 140-g silica cartridge
10. washeluted with hexanes
11. concentrationconcentrated

ORD record

ord-5448868ecc834b0187ad4ed1a6f54691

Source dataset

uspto-grants-2010_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07754737B2