反应详情

Diethyl ethoxymethylene-malonate (5.20 ml; 26 mmol) was added rapidly to 2.75 ml (28 mmol) of phenylhydrazine in 15 ml of methanol and the resulting mixture was refluxed for 4 hours. The mixture was cooled and concentrated in vacuo, and the residue was crystallized from ethanol to afford 5.82 g (97%) of 2,4-dihydro-2-phenyl-4-ethoxycarbonyl-3H-pyrazol-3-one (Formula III: R1 =Ph; R2 =H; R3 =C(O)OEt) as white needles, m.p. 106°-107° C.

1. temperaturethe resulting mixture was refluxed for 4 hours
2. temperatureThe mixture was cooled
3. concentrationconcentrated in vacuo
4. customthe residue was crystallized from ethanol