反应详情

A mixture of 5-(4-fluorophenyl)-1-methyl-1H-pyrazole-4-carbaldehyde (350 mg), sodium hydride (60% in oil, 120 mg), ethyl diethylphosphonoacetate (673 mg) and N,N-dimethylformamide (10 ml) was stirred at room temperature for 1 hr. The reaction mixture was poured into water, and the precipitated solids were collected by filtration. After drying with airflow, the solids were dissolved in a mixed solvent of tetrahydrofuran (10 ml) and ethanol (10 ml). A 1N aqueous sodium hydroxide solution (5 ml) was added and the mixture was stirred at room temperature for 2 hrs. The reaction mixture was poured into a 10% aqueous citric acid solution and the precipitated solids were collected by filtration, washed with water and dried with airflow to give (2E)-3-[5-(4-fluorophenyl)-1-methyl-1H-pyrazol-4-yl]acrylic acid (354 mg, 84%) as crystals. Recrystallization thereof from methanol-isopropyl ether gave colorless prism crystals. melting point: 212-213° C.

1. filtrationthe precipitated solids were collected by filtration
2. customAfter drying with airflow
3. dissolutionthe solids were dissolved in a mixed solvent of tetrahydrofuran (10 ml) and ethanol (10 ml)
4. additionA 1N aqueous sodium hydroxide solution (5 ml) was added
5. stirringthe mixture was stirred at room temperature for 2 hrs
6. additionThe reaction mixture was poured into a 10% aqueous citric acid solution
7. filtrationthe precipitated solids were collected by filtration
8. washwashed with water
9. customdried with airflow