Reaktion #540264

Reaktionsgleichung

potassium persulfate

ethyl 3-bromo-1-(3,5-dichloropyridin-2-yl)-4,5-dihydro-1H-pyrazole-5-carboxylate

sulfuric acid

→

product

Ausbeute 81.2%

ethyl 3-bromo-1-(3,5-dichloropyridin-2-yl)-1H-pyrazole-5-carboxylate

Ausbeute 81.2%

Lösungsmittel

acetonitrile

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe reaction mixture was heated
2. 2
   Temperaturto reflux for 5 hours
3. 3
   TemperaturThe warm
4. 4
   Sonstige(50-65° C.) reaction mixture
5. 5
   Filtrationwas filtered
6. 6
   Sonstigea cake is obtained
7. 7
   WaschenThe cake was washed by acetonitrile (10 mL)
8. 8
   EinengenThe filtrate was concentrated to about 10 mL on rotary evaporator
9. 9
   workup.ADDITIONThen water (50 mL) was added
10. 10
    SonstigeThe solid product was isolated by filtration
11. 11
    Waschenwashed with 25% aqueous solution of acetonitrile (3×15 mL)
12. 12
    Sonstigedried

Vorschrift

To a 100 mL flask, ethyl 3-bromo-1-(3,5-dichloropyridin-2-yl)-4,5-dihydro-1H-pyrazole-5-carboxylate (2.0 g, 5.4 mmol), acetonitrile (10 mL) and 98% sulfuric acid (1.1 g, 10.9 mmol) were added. The mixture was stirred for a few minutes, and then potassium persulfate (2.4 g, 8.7 mmol) was added. The reaction mixture was heated to reflux for 5 hours. The warm (50-65° C.) reaction mixture was filtered, a cake is obtained. The cake was washed by acetonitrile (10 mL). The filtrate was concentrated to about 10 mL on rotary evaporator. Then water (50 mL) was added. The solid product was isolated by filtration, washed with 25% aqueous solution of acetonitrile (3×15 mL) and dried to give the product (1.6 g) as orange solid in 80% yield.

Quelle