反应详情

温度

20 °C

20 ml of a 30% strength sodium methylate solution are added dropwise to a suspension of 16.9 g of 5-methoxy-2-methyl-4-nitropyridine 1-oxide in 170 ml of dry methanol and the mixture is stirred at 20° C. for 15 hours and then at 50° C. for 4 hours. The pH is brought to 7 by careful addition of concentrated sulfuric acid, while cooling with ice, the mixture is concentrated, the residue is extracted by stirring with 200 ml of methylene chloride, the insoluble constituents are filtered off, 10 ml of toluene are added and the mixture is concentrated to dryness again. 15.2 g (98% of theory) of 4,5-dimethoxy-2-methylpyridine-1-oxide are obtained as colorless crystals of m.p. 118°-121° C.

1. waitat 50° C. for 4 hours
2. temperaturewhile cooling with ice
3. concentrationthe mixture is concentrated
4. extractionthe residue is extracted
5. stirringby stirring with 200 ml of methylene chloride
6. filtrationthe insoluble constituents are filtered off
7. addition10 ml of toluene are added
8. concentrationthe mixture is concentrated to dryness again