反应详情

A solution of triethyl 1,6-dihydro-6-oxo-2,3,5-pyridinetricarboxylate (39.7 g) in 300 mL of phosphorous oxychloride and 0.5 mL dimethylformamide is stirred at 100° C. for four hours and 15 minutes. After cooling, the excess phosphorous oxychloride is removed under vacuum. The residue is taken up in 200 mL methylene chloride and the solution poured into 500 mL of ice water and the layers are separated. The aqueous layer, made basic with concentrated ammonium hydroxide and ice, is extracted with 150 mL methylene chloride. The combined methylene chloride extracts are dried over magnesium sulfate, filtered and concentrated under vacuum, and the resulting crude product is chromatographed on silica using 5:1 hexanes:ethyl acetate and then 4:1 hexanes:ethyl acetate as eluants affording 26.5 g (47%) of the title product as an oil.

1. temperatureAfter cooling
2. customthe excess phosphorous oxychloride is removed under vacuum
3. additionthe solution poured into 500 mL of ice water
4. customthe layers are separated
5. extractionis extracted with 150 mL methylene chloride
6. dry with materialThe combined methylene chloride extracts are dried over magnesium sulfate
7. filtrationfiltered
8. concentrationconcentrated under vacuum
9. customthe resulting crude product is chromatographed on silica using 5:1 hexanes