反应详情

The mixture of 3-chloro-5-formyl-2H-pyridine-1-carboxylic acid phenyl ester (2.3 g, 8.8 mmol), sublimed sulfur (0.29 g, 9 mmol) and naphthalene (6 g) was refluxed under an argon atmosphere for 2 h. After the reaction was complete, the mixture was cooled to r.t., dissolved in ethyl ether (30 mL), and extracted with aqueous 10% HCl. The combined acid extracts were washed with ethyl ether (20 mL) and cooled to 0° C. Dichloromethane (30 mL) was added and “pH” of the mixture was adjusted to be basic with 25% aqueous NaOH, and the mixture was extracted with dichloromethane (20 mL). The combined organic phase was washed with brine, dried over K2CO3, filtered, and concentrated to give a brown solid. (0.8 g, 76%).

1. temperaturewas refluxed under an argon atmosphere for 2 h
2. extractionextracted with aqueous 10% HCl
3. washThe combined acid extracts were washed with ethyl ether (20 mL)
4. temperaturecooled to 0° C
5. additionDichloromethane (30 mL) was added
6. extractionthe mixture was extracted with dichloromethane (20 mL)
7. washThe combined organic phase was washed with brine
8. dry with materialdried over K2CO3
9. filtrationfiltered
10. concentrationconcentrated
11. customto give a brown solid