Reaktion #90227

Reaktionsgleichung

ethyl 1-(3-chloro-2-pyridinyl)-4,5-dihydro-5-hydroxy-3-(trifluoromethyl)-1H-pyrazole-5-carboxylate

product

ethyl 1-(3-chloro-2-pyridinyl)-4,5-dihydro-5-hydroxy-3-(trifluoromethyl)-1H-pyrazole-5-carboxylate

→

product

Ausbeute 77.0%

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

Ausbeute 77.0%

Lösungsmittel

acetic acid

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigewas removed under reduced pressure
2. 2
   SonstigeThe mixture was partitioned between saturated aqueous sodium carbonate solution (100 mL) and ethyl acetate (100 mL)
3. 3
   ExtraktionThe aqueous layer was further extracted with ethyl acetate (100 mL)
4. 4
   SonstigeThe combined organic extracts were dried
5. 5
   Sonstigeevaporated

Vorschrift

Sulfuric acid (concentrated, 2 drops) was added to ethyl 1-(3-chloro-2-pyridinyl)-4,5-dihydro-5-hydroxy-3-(trifluoromethyl)-1H-pyrazole-5-carboxylate (i.e. the product of Step C) (1 g, 2.96 mmol) in acetic acid (10 mL) and the mixture was warmed to 65° C. for about 1 hour. The mixture was allowed to cool to 25° C. and most of the acetic acid was removed under reduced pressure. The mixture was partitioned between saturated aqueous sodium carbonate solution (100 mL) and ethyl acetate (100 mL). The aqueous layer was further extracted with ethyl acetate (100 mL). The combined organic extracts were dried and evaporated to give the product as an oil (0.66 g, 77% yield).

Quelle