Reaction #792180

Reaction equation

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

Yield 77.0%

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

Yield 77.0%

Solvents

acetic acid

acetic acid

Conditions

Workup

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

Procedure

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).

Source