反应详情

温度

80 °C

30 g (173mmol) of 4-chloro-3-methoxy-2-methylpyridine N-oxide (cf. Example 1a) were dissolved in 100 ml of glacial acetic acid, after which 150 ml of acetic anhydride were added dropwise, at 80° C. and while stirring, and the mixture was then stirred at 110° C. for 2 h. The mixture was then cooled down to 80° C. and 200 ml of methanol were added dropwise; the mixture was then heated to boiling for 15 min. and, after having been cooled down, concentrated in vacuo; the residue was taken up in methanol and this mixture was allowed to flow into 300 ml of 1.5N methanolic sodium hydroxide solution, with this mixture then being stirred at 20° C. for 30 min. and concentrated in vacuo; the residue was taken up in water, and this mixture extracted three times with dichloromethane, with the organic phase being dried and concentrated; the residue was crystallized using petroleum ether. 23 g of product were obtained, m.p. 64°-66° C.

1. stirringthe mixture was then stirred at 110° C. for 2 h
2. temperaturethe mixture was then heated
3. temperatureafter having been cooled down
4. concentrationconcentrated in vacuo
5. stirringthen being stirred at 20° C. for 30 min.
6. concentrationconcentrated in vacuo
7. extractionthis mixture extracted three times with dichloromethane
8. customwith the organic phase being dried
9. concentrationconcentrated
10. customthe residue was crystallized