反应详情

The mixture of 3-hydrazinobenzoic acid (5.0 g) and ethyl 2-ethoxymethylene-2-cyanoacetate (5.6 g) in ethanol (50 ml) was heated under reflux for 2 hours under stirring, and then the mixture was evaporated in vacuo. To the residue was added a mixture of ethyl acetate and water, and the mixture was adjusted to pH 8 with 20% aqueous potassium carbonate solution. The separated aqueous layer was adjusted to pH 4 with 6N-hydrochloric acid and extracted with ethyl acetate. The extract layer was washed with water, dried over magnesium sulfate and evaporated in vacuo. The residue was triturated with a solution of ethyl acetate and diisopropyl ether and the precipitate was collected by filtration to give 3-(5-amino-4-ethoxycarbonylpyrazol-1-yl)benzoic acid (6.0 g).

1. temperaturewas heated
2. temperatureunder reflux for 2 hours
3. customthe mixture was evaporated in vacuo
4. additionTo the residue was added
5. additiona mixture of ethyl acetate and water
6. extractionextracted with ethyl acetate
7. washThe extract layer was washed with water
8. dry with materialdried over magnesium sulfate
9. customevaporated in vacuo
10. customThe residue was triturated with a solution of ethyl acetate and diisopropyl ether
11. filtrationthe precipitate was collected by filtration