反应详情

To a flask containing 2-chloro-6-(4-chlorophenyl)pyrazine (2.35 g, 10.4 mmol), was added phosphorus tribromide (17 mL) and the mixture heated at reflux for 6 h under nitrogen. The reaction mixture was cooled to room temperature prior to pouring carefully into iced water (600 mL) the resulting mixture was adjusted to pH 6–7 using aqueous ammonia and extracted with diethyl ether (2×250 mL). The organic solution was dried (MgSO4) and the solvent removed in vacuo. The reaction had not gone to completion so the residue was treated with added phosphorus tribromide (17 mL) and heated at reflux for a further 5 h under nitrogen. Work up as before afforded the title compound as a pale yellow solid (0.97 g).

1. temperaturethe mixture heated
2. temperatureat reflux for 6 h under nitrogen
3. extractionextracted with diethyl ether (2×250 mL)
4. dry with materialThe organic solution was dried (MgSO4)
5. customthe solvent removed in vacuo
6. additionwas treated with added phosphorus tribromide (17 mL)
7. temperatureheated
8. temperatureat reflux for a further 5 h under nitrogen