反应详情

A solution of 4-nitropyrazole (5.6 g, 50 mmol)in ethanol (200 ml) was hydrogenated over 10% palladium on charcoal (0.5 g) at room temperature and pressure for 3.5 h. The catalyst was filtered off and ethyl 2-acetyl-3-ethoxyacrylate (9.3 g, 50 mmol) was added to the solution under nitrogen. After 5 min, the solution was evaporated in vacuo and the residual solid was recrystallised from ethyl acetate/pentane (charcoal) to give the title compound (7.7 g, 69%), m.p. 126°-128° C. Found: C, 49.96; H, 6.28; N, 17.34%. C10H13N3O3.H2O requires C, 49.78; H, 6.27; N, 17.41%.

1. filtrationThe catalyst was filtered off
2. waitAfter 5 min
3. customthe solution was evaporated in vacuo
4. customthe residual solid was recrystallised from ethyl acetate/pentane (charcoal)