反应详情

6.2 grams 3,3-dibenzoyl-propionic acid-ethyl ester, 1.0 gram methyl hydrazine and 4 grams glacial acetic acid were mixed and the mixture heated to the boiling temperature under reflux for 4 hours. The reaction mixture was then evaporated, the residue taken up in benzene and extracted with water. The benzene was then distilled from the benzene phase and the reside, consituting the crude ester reaction product, was heated with 2.0 grams sodium hydroxide, 20 milliliters ethanol and 20 milliliters water to the boiling temperature under reflux for 2 hours. The reaction mixture was then worked up and the reaction product was recovered by the general procedure set out in Example (2a). The recovered free acid was recrystallized from a mixture of benzene and petroleum ether boiling in a range from 50°-70° C. 3.9 grams 1-methyl-3,5-diphenyl-pyrazol-4-acetic acid, melting at 170°-172° C., were obtained, representing a yield of 67%.

1. temperaturethe mixture heated to the boiling temperature
2. temperatureunder reflux for 4 hours
3. customThe reaction mixture was then evaporated
4. extractionextracted with water
5. distillationThe benzene was then distilled from the benzene phase
6. customthe crude ester reaction product
7. temperatureunder reflux for 2 hours
8. customthe reaction product was recovered by the general procedure
9. customThe recovered free acid was recrystallized from a mixture of benzene and petroleum ether boiling in a range from 50°-70° C