Ethyl bromoacetate → ethyl [4-(4-fluorophenyl)-3-[4-(methylsulfonyl)phenyl]-5-(trifluoromethyl)-1H-pyrazol-1-yl]acetate

Participants

Reaction Steps

4-(4-Fluorophenyl)-3-[4-(methylsulfonyl)phenyl]-5-(trifluoromethyl)-1H-pyrazole (Example 1, Step 3) (2.11 g, 5.5 mmol) and ethyl bromoacetate (1.09 g, 6.5 mmol) were stirred vigorously in 15 mL dry DMF with finely powdered potassium carbonate (1.38 g, 10 mmol) under nitrogen at 25° C. for 3 hours. The mixture was diluted with ethyl acetate and filtered to remove solids. The organic filtrate was washed with two portions of water followed by brine, dried over MgSO4 and concentrated in vacuo. The desired isomer was isolated by chromatography on silica gel, using 10% ethyl acetate/90% heptane as the eluant, to give ethyl [4-(4-fluorophenyl)-3-[4-(methylsulfonyl)phenyl]-5-(trifluoromethyl)-1H-pyrazol-1-yl]acetate as a white solid (0.87 g, 34%). Elemental analysis for C21H18N2F4SO4Calc'd: C, 53.62, H, 3.86, N, 5.96, S, 6.82. Found: C, 53.69, H, 3.97, N, 5.87, S. 7.05.

Provenance & Evidence