Reaction #792175

Reaction equation

potassium carbonate

Water

ethyl 1-(3-chloro-2-pyridinyl)-2,3-dihydro-3-oxo-1H-pyrazole-5-carboxylate

Ethyl 1-(3-chloro-2-pyridinyl)-2,3-dihydro-3-oxo-1H-pyrazole-5-carboxylate

product

Ethyl 1-(3-chloro-2-pyridinyl)-2,3-dihydro-3-oxo-1H-pyrazole-5-carboxylate

2,2,2-trifluoroethyl trifluoromethanesulfonate

→

title product

Ethyl 1-(3-chloro-2-pyridinyl)-3-(2,2,2-trifluoroethoxy)-1H-pyrazole-5-carboxylate

Solvents

acetonitrile

Conditions

Workup

1. 1
   TemperatureThe stirred suspension was then cooled to 5° C.
2. 2
   TemperatureThe reaction mixture was warmed to room temperature
3. 3
   Temperatureheated
4. 4
   Temperatureto reflux, at which time thin layer chromatography
5. 5
   Otherthe reaction
6. 6
   Extractionwas then extracted with ethyl ether
7. 7
   ExtractionThe ether extract
8. 8
   Dryingwas dried over magnesium sulfate
9. 9
   Concentrationconcentrated

Procedure

To a suspension of ethyl 1-(3-chloro-2-pyridinyl)-2,3-dihydro-3-oxo-1H-pyrazole-5-carboxylate (i.e. product of Step A) (0.8 g, 3 mmol) stirred in dry acetonitrile (15 mL) at −5° C. was added potassium carbonate (0.85 g, 6.15 mmol). The suspension was stirred for 15 minutes at 20° C. The stirred suspension was then cooled to 5° C., and 2,2,2-trifluoroethyl trifluoromethanesulfonate (0.8 g, 3.45 mmol) was added dropwise. The reaction mixture was warmed to room temperature and then heated to reflux, at which time thin layer chromatography showed the reaction to be complete. Water (25 mL) was added to the reaction mixture, which was then extracted with ethyl ether. The ether extract was dried over magnesium sulfate and concentrated to yield the title product compound (1.05 g) as a pale yellow oil.

Source