| Molecular Formula | C8H12N2O2 |
| Molar Mass | 168.19308 |
| Physical and Chemical Properties | The chemical product is light brown oil. |
| Use | Use 3-ethylpyrazole-5-carboxylic acid ethyl ester is an intermediate of the acaricide pyaramide. |
The preparation method is to react ethyl propionyl pyruvate with hydrazine hydrate at 15°C under alkaline conditions to obtain the product.
Dihydrazine sulfate can also be used as a raw material for the reaction. For example, ethyl propionyl pyruvate, potassium sulfate and water are mixed and dissolved at room temperature to form a saturated aqueous solution, the ice bath is cooled to 0~5 ℃, the aqueous solution containing dihydrazine sulfate is added dropwise under stirring, the dropwise acceleration is controlled, the reaction temperature is not more than 25 ℃, the dropwise addition is completed for about 0.5h, the stirring is maintained under the ice bath for 0.5~1, add 50mL chloroform mixed to dissolve and extract, separate the chloroform layer, then extract the water layer with 30mL × 3 chloroform, and distill the separated chloroform to obtain the product. Mother liquor can be recycled.