Reaktion #339196

Reaktionsgleichung

potassium persulfate

ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate

sulfuric acid

→

ethyl 1-(3-chloro-2-pyridinyl)-3-hydroxy-1H-pyrazole-5-carboxylate

Ausbeute 60.7%

Lösungsmittel

acetonitrile

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe resulting mixture was heated
2. 2
   Temperaturto reflux for 3.5 hours
3. 3
   Filtrationfiltered
4. 4
   workup.ADDITIONWater was poured into the filtrate
5. 5
   Extraktionthe mixture was extracted with methyl tert-butyl ether three times
6. 6
   Waschenwashed with an aqueous saturated sodium chloride solution
7. 7
   Trocknendried over anhydrous magnesium sulfate
8. 8
   Einengenconcentrated under reduced pressure

Vorschrift

To a mixture of 12.0 g of ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate, 90 ml of acetonitrile and 4.8 ml of sulfuric acid was added 14.5 g of potassium persulfate. The resulting mixture was heated to reflux for 3.5 hours. The reaction mixture was allowed to cool to room temperature, and filtered. Water was poured into the filtrate, and the mixture was extracted with methyl tert-butyl ether three times. The organic layers were combined, washed with an aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The resulting residue was subjected to silica gel chromatography to obtain 7.23 g of ethyl 1-(3-chloro-2-pyridinyl)-3-hydroxy-1H-pyrazole-5-carboxylate of the formula:

Quelle