| 摘要 |
PURPOSE: A method of a pyrazole synthesis by coupling carboxylic acid derivatives and enamines is provided to prepare pyrazoles by converting enamines and carboxylic acid derivatives in the presence of an oxidizing agent. CONSTITUTION: A method of preparing pyrazoles, by converting enamines and N-containing carboxylic acid derivatives in the presence of an oxidizing agent, copper ions, and 2-picolinic acid derivatives, is provided. The N-containing carboxylic acid is selected from the group consisting of: nitriles, carboxylic acid amides, amidines, imidates, imidoyl chlorides, derived protonated salts of these compounds, and mixtures thereof. The conversion is carried out in the presence of Cu (II) salts. The ratio of enamines to Cu (II) salts amounts to >=1.5:1 to <=30:1 (mole of Cu (II) salts to mole of enamines). The ratio of 2-picolinic acid derivatives to enamines amounts to >=0.01% to <=10% (mole/mole). |
