反应详情

6 g (60% strength) of NaH are added in portions to 50 ml of dry dioxane, the mixture is stirred for 15 minutes, 11.7 g (0.11 mol) of 2-furylmethylmercaptan are metered in over a period of 20 minutes and the mixture is stirred again for 30 minutes until the evolution of gas has ended. A solution of 14.4 g (0.1 mol) of 4-chloro-2,3-dimethylpyridine N-oxide in 100 ml of dioxane is then added dropwise in the course of 20 minutes, and the reaction mixture is stirred at RT for 1 h, subsequently at 70° C. for 1 h and then at 100° C. for another 1 h. When the reaction has ended, the mixture is allowed to cool and is diluted with 500 ml of water and extracted 4 times with 300 ml of ethyl acetate each time. The combined organic phases are washed with water, dried over magnesium sulfate and concentrated and the residue is crystallized by addition of diisopropyl ether. 18.8 g (80% of theory) of 2,3-dimethyl-4-(2-furylmethylthio)-pyridine N-oxide of m.p. 111-112° C. are obtained.

1. customare metered in over a period of 20 minutes
2. stirringthe mixture is stirred again for 30 minutes until the evolution of gas
3. stirringthe reaction mixture is stirred at RT for 1 h, subsequently at 70° C. for 1 h
4. waitat 100° C. for another 1 h
5. temperatureto cool
6. extractionextracted 4 times with 300 ml of ethyl acetate each time
7. washThe combined organic phases are washed with water
8. dry with materialdried over magnesium sulfate
9. concentrationconcentrated
10. customthe residue is crystallized by addition of diisopropyl ether