反应详情

温度

85 °C

A mixture of ethyl 4-hydroxy-1,5-dimethyl-6-oxo-1,6-dihydropyridazine-3-carboxylate (1.85 g, 8.72 mmol) and POCl3 (9 mL) was heated for 16 hours at 85° C. POCl3 was removed under reduced pressure. Then the crude material was quenched with ice-water. The mixture was neutralized with saturated aqueous NaHCO3 (pH ˜6 to 7) and extracted with EtOAc (3×). The combined organic layers were dried over MgSO4, filtered, and concentrated under reduced pressure to give the crude material that was purified by silica gel flash column chromatography (100% hexanes to 5 to 10 to 20% EtOAc in hexanes) to afford 1.72 g (86%) of the desired product.

1. customPOCl3 was removed under reduced pressure
2. customThen the crude material was quenched with ice-water
3. extractionextracted with EtOAc (3×)
4. dry with materialThe combined organic layers were dried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customto give the crude material that
8. customwas purified by silica gel flash column chromatography (100% hexanes to 5 to 10 to 20% EtOAc in hexanes)