Reaction #1583839
ord-3335699b181744cdbf01d50fee3dda87
Reaction equation
Reactants
Reagents
Solvents
Conditions
Workup
- 1workup.ADDITIONthe addition
- 2Temperaturewhile heating
- 3Temperatureat reflux
- 4TemperatureHeating
- 5workup.WAITwas continued for 2 h at −65° C.
- 6Temperatureto warm to room temperature
- 7workup.STIRRINGstirred for 2 h
- 8Extractionextracted with ethyl acetate (2×)
Procedure
To a mixture of magnesium turnings (0.17 g, 6.98 mmol) and 1,2-dibromoethane (2 drops) in tetrahydrofuran (0.5 mL) under a nitrogen atmosphere was added dropwise a solution of 3-(3-bromo-4-methylphenyl)-1-[3-(trifluoromethyl)phenyl]-1H-pyrazole (i.e. the product of Step C) (2.0 g, 5.25 mmol) in tetrahydrofuran (3.5 mL). After about 2% of the total volume of the 3-(3-bromo-4-methylphenyl)-1-[3-(trifluoromethyl)phenyl]-1H-pyrazole solution had been added, the addition was stopped and iodine (catalytic amount) was added to the reaction mixture. The remaining 3-(3-bromo-4-methylphenyl)-1-[3-(trifluoromethyl)-phenyl]-1H-pyrazole solution was then added to the reaction mixture over 1 h while heating at reflux. Heating was continued for an additional 45 minutes, and then the reaction mixture was cooled to room temperature. The reaction mixture was added via an addition funnel to a solution of oxalyl chloride (0.508 mL, 5.82 mmol) in tetrahydrofuran (6 mL) at −65° C. Stirring was continued for 2 h at −65° C., and then methanol (1.17 mL) was added to the reaction mixture, and the mixture was allowed to warm to room temperature and stirred for 2 h. The reaction mixture was diluted with saturated aqueous ammonium chloride (4 mL) and water (8 mL) and then extracted with ethyl acetate (2×).