反应详情

温度

55 °C

Under ice-cooling, 98% formic acid (12.75 g) was added to acetic anhydride (22.97 g) using an dropping funnel, the obtained mixture was stirred at 50-60° C. for 2 hrs, and cooled to room temperature. Tetrahydrofuran (25 mL) was added to the obtained mixture and a solution of ethyl 3-amino-1-phenyl-1H-pyrazole-4-carboxylate (20.00 g) in tetrahydrofuran (20 mL) was added. The obtained mixture was stirred at room temperature for 3 hrs and concentrated. The residue was recrystallized from ethyl acetate-hexane to give ethyl 3-(formylamino)-1-phenyl-1H-pyrazole-4-carboxylate as colorless needle crystals (20.89 g, yield 93%). melting point: 135-136° C.

1. temperatureUnder ice-cooling
2. temperaturecooled to room temperature
3. stirringThe obtained mixture was stirred at room temperature for 3 hrs
4. concentrationconcentrated
5. customThe residue was recrystallized from ethyl acetate-hexane