Reaktion #40769

Reaktionsgleichung

hydrazine hydrate

NaOH

3-dimethylamino-1-phenyl-propan-1-one hydrochloride

→

yellow oil

3-Phenyl-4,5-dihydro-1H-pyrazole

Lösungsmittel

MeOH

MeOH

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was refluxed for 2 hours
2. 2
   Sonstigeevaporated under reduced pressure
3. 3
   workup.ADDITIONIce water was added to the residue
4. 4
   workup.STIRRINGafter stirring for 5 minutes the formed solid
5. 5
   Filtrationwas filtered off
6. 6
   Trocknendried over Na2SO4
7. 7
   Sonstigeevaporated to dryness under reduced pressure

Vorschrift

Under N2 atmosphere, 3-dimethylamino-1-phenyl-propan-1-one hydrochloride (37.2 g) was dissolved in warm MeOH (75 mL), and slowly added to a solution of hydrazine hydrate (23 mL) and 50% aqueous NaOH (12 mL) in MeOH (30 mL) stirred at 50° C. The mixture was refluxed for 2 hours and evaporated under reduced pressure. Ice water was added to the residue and after stirring for 5 minutes the formed solid was filtered off. The residue was taken up in Et2O, dried over Na2SO4, and evaporated to dryness under reduced pressure to give 19.7 g of a yellow oil being 80% pure, which was used in subsequent steps without further purification.

Quelle