Study on synthesis of ethyl, 3-ethyl-1-methyl-5-pyrazolecarboxylate

Abstrcat Ethyl, 3-ethyl-1-methyl-5-pyrazolecarboxylate synthesized by means of Knorr Reaction is an important intermediate of tebufenpyrad. After the optimized test of temperature and solvent, ethyl propionylpyruvate was produced in ethy1 ether at 5 ℃ of a yield above 90%. The product content is above 95%. Ethyl, 3-ethyl-1-methyl-5-pyrazolecarboxylate was produced of a yield above 85% and product content above 95% with the molar ratio above 1∶1.2 at 0 ℃, after the optimized test of temperature and the molar ratio between ethyl propionylpyruvate and methylhydrazine. The product was characterized by MS,()~1HNMR, IR.