反应详情

Part C: To a stirred suspension of ethyl 1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxylate (23.0 gram, 0.07 mol) in methanol (200 ml) is added water (15 ml) and concentrated NaOH (10 ml) and the resulting solution is heated at reflux temperature for 2 hours. The methanol is partly removed by evaporation and the residue is dissolved in a mixture of water and ethyl acetate. Ice, concentrated HCl (20 ml) and ethyl acetate are successively added, the ethyl acetate layer collected, dried over MgSO4, filtered and concentrated in vacuo. The resulting residue is washed with diethyl ether (100 ml) and diisopropyl ether respectively, to give 1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxylic acid (16.46 gram, 78% yield). Melting point: 177-179° C.

1. temperaturethe resulting solution is heated
2. temperatureat reflux temperature for 2 hours
3. customThe methanol is partly removed by evaporation
4. dissolutionthe residue is dissolved in a mixture of water and ethyl acetate
5. additionIce, concentrated HCl (20 ml) and ethyl acetate are successively added
6. customthe ethyl acetate layer collected
7. dry with materialdried over MgSO4
8. filtrationfiltered
9. concentrationconcentrated in vacuo
10. washThe resulting residue is washed with diethyl ether (100 ml) and diisopropyl ether respectively