反应详情

Triethylamine (28.8 mL, 206 mmol) was added to a nitrogen purged solution of 3,5-dibromo-2,6-dimethylpyridin-4-ol (58 g, 206 mmol) and phosphorous oxychloride (57.7 mL, 619 mmol) in chloroform (450 mL) and stirred for 1 h at rt, then 3 h at 80° C. The reaction was removed from heating and immediately concentrated under house vaccum; then under high vacuum. The appearance was a cream colored solid, which was azeotroped with toluene (2×100 mL); treated with ice (200 g) for 10 min and carefully neutralized with NaHCO3 (powder), and 1N NaOH solution, and extracted with DCM (2×400 mL). The combined organic layers were dried (MgSO4), concentrated, and a beige solid was obtained that was washed with hexanes and dried under high vacuum to give 3,5-dibromo-4-chloro-2,6-dimethyl-pyridine 52.74 g (85.1%). Concentration of the hexanes gave 3.5 g of less pure product.

1. custom3 h
2. customat 80° C
3. customThe reaction was removed
4. temperaturefrom heating
5. concentrationimmediately concentrated under house vaccum
6. customwas azeotroped with toluene (2×100 mL)
7. additiontreated with ice (200 g) for 10 min
8. extractionextracted with DCM (2×400 mL)
9. dry with materialThe combined organic layers were dried (MgSO4)
10. concentrationconcentrated
11. customa beige solid was obtained
12. washthat was washed with hexanes
13. customdried under high vacuum