反应详情

Chlorobenzene (100 mL) and polyphosphoric acid (30.4 g, PPA) were combined and heated to reflux. The 2-(2-bromophenylthio) acetaldehyde diethyl acetal (13.7 g, 44.88 mmol, Scheme I, step A above) dissolved in chlorobenzene (20 mL) was added dropwise to the refluxing mixture over 20 minutes. The reaction was refluxed for 4 hours and then cooled. The solvent was decanted from the residue and toluene (2×50 mL) was added to the residue, stirred and decanted. The chlorobenzene/toluene extracts were concentrated under vacuum and the residue taken up in ethyl acetate and water. The organic phase was washed with saturated sodium bicarbonate, dried over anhydrous sodium sulfate, filtered and concentrated to provide 7-bromobenzo(b)thiophene (8.91 g, 93%).

1. temperatureheated to reflux
2. additionwas added dropwise to the refluxing mixture over 20 minutes
3. temperatureThe reaction was refluxed for 4 hours
4. temperaturecooled
5. customThe solvent was decanted from the residue and toluene (2×50 mL)
6. additionwas added to the residue
7. customdecanted
8. concentrationThe chlorobenzene/toluene extracts were concentrated under vacuum
9. washThe organic phase was washed with saturated sodium bicarbonate
10. dry with materialdried over anhydrous sodium sulfate
11. filtrationfiltered
12. concentrationconcentrated