反应详情

温度

80 °C

Hydrazine hydrate (41.7 μL, 0.4 mmol) was added to a stirred solution of 2,4-dioxo-5-phenoxy-hexanoic acid ethyl ester (566 mg, 2.14 mmol) in EtOH (4.5 mL). The mixture was stirred at 80° C. for 1 hour. Then, the mixture was stirred at room temperature for 16 hours. Hydrazine hydrate (20 μL, 0.2 mmol) was added and the mixture was stirred at 80° C. for 2 hours. More hydrazine hydrate (41.7 μL, 0.4 mmol) was added and the mixture was stirred at 80° C. for 2 hours. The solvent was evaporated in vacuo. The crude product was purified by flash column chromatography (silica, AcOEt in DCM 0/100 to 20/80). The desired fractions were collected and solvents evaporated in vacuo to yield (rac)-5-(1-phenoxy-ethyl)-2H-pyrazole-3-carboxylic acid ethyl ester (467 mg, 78% yield) as a colourless oil.

1. stirringThen, the mixture was stirred at room temperature for 16 hours
2. stirringthe mixture was stirred at 80° C. for 2 hours
3. stirringthe mixture was stirred at 80° C. for 2 hours
4. customThe solvent was evaporated in vacuo
5. customThe crude product was purified by flash column chromatography (silica, AcOEt in DCM 0/100 to 20/80)
6. customThe desired fractions were collected
7. customsolvents evaporated in vacuo