反应详情

温度

40 °C

4.5 g (25 mmol) of 3-methoxy-2-methyl-4-nitropyridine 1-oxide are stirred at 40° C. in 75 ml of dry methanol, after addition of 4.7 ml of 30% strength sodium methylate solution, for 16 hours. The mixture is then cooled, brought to pH 7 with concentrated sulphuric acid, filtered and concentrated completely in vacuo, the oily, reddish residue is taken up in 50 ml of toluene, the mixture is filtered again to remove insoluble constituents and the filtrate is concentrated to dryness. The yellow oily residue crystallises in an ice-bath and is finally extracted by stirring with 30 ml of petroleum ether (50/70) at 40° C. Filtration and drying in a desiccator gives 5.2 g (88% of theory) of 3,4-dimethoxy-2-methylpyridine 1-oxide in the form of pale yellow crystals of m.p. 111°-113° C.

1. temperatureThe mixture is then cooled
2. filtrationfiltered
3. concentrationconcentrated completely in vacuo
4. filtrationthe mixture is filtered again
5. customto remove insoluble constituents
6. concentrationthe filtrate is concentrated to dryness
7. customThe yellow oily residue crystallises in an ice-bath
8. extractionis finally extracted
9. filtrationFiltration
10. customdrying in a desiccator