Reaktion #48035

Reaktionsgleichung

ethyl 1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxylate

water

NaOH

→

1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxylic acid

Ausbeute 78.2%

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe resulting solution is heated
2. 2
   Temperaturat reflux temperature for 2 hours
3. 3
   SonstigeThe methanol is partly removed by evaporation
4. 4
   workup.DISSOLUTIONthe residue is dissolved in a mixture of water and ethyl acetate
5. 5
   workup.ADDITIONIce, concentrated HCl (20 ml) and ethyl acetate are successively added
6. 6
   Sonstigethe ethyl acetate layer collected
7. 7
   Trocknendried over MgSO4
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated in vacuo
10. 10
    WaschenThe resulting residue is washed with diethyl ether (100 ml) and diisopropyl ether respectively

Vorschrift

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.

Quelle