反应详情

温度

0 °C

183 g (1.56 mol) of isopentyl nitrite are added dropwise to 175 g (1.56 mol) of 1,3-dimethyl-pyrazolin-5-one and 84.4 g (1.56 mol) of sodium methylate in 1 L of absolute ethanol, while stirring and cooling with ice so that the internal temperature does not rise above 25° C. to 30° C. When the addition has ended, stirring is continued at room temperature for 24 hours and the sodium salt of 1,3-dimethyl-4-hydroximino-pyrazolin-5-one which has precipitated is filtered off with suction. The crystalline product is dissolved in 1 L of water and the solution is acidified with glacial acetic acid. For complete precipitation, the mixture is cooled at 0° C. for several hours, and the product is then filtered off with suction. 162 g (74% of theory) of 1,3-dimethyl-4-hydroximino-pyrazolin-5-one of melting point 93° C. are obtained.

1. temperaturecooling with ice so that the internal temperature
2. customdoes not rise above 25° C. to 30° C
3. additionWhen the addition
4. stirringstirring
5. customthe sodium salt of 1,3-dimethyl-4-hydroximino-pyrazolin-5-one which has precipitated
6. filtrationis filtered off with suction
7. dissolutionThe crystalline product is dissolved in 1 L of water
8. customFor complete precipitation
9. filtrationthe product is then filtered off with suction