Trifluoroacetic acid → 2-ethyl-5-(4-fluoro-benzylamino)-2H-pyrazole-3-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To 5-amino-2-ethyl-2H-pyrazole-3-carboxylic acid methyl ester (527, 1.00 g, 5.91 mmol) in acetonitrile (27.5 mL) were added 4-fluorobenzaldehyde (528, 0.660 mL, 6.26 mmol), triethylsilane (4.77 mL, 0.0298 mol) and trifluoroacetic acid (2.38 mL, 0.0310 mol). The reaction was stirred at 80° C. for 4 hours, then concentrated, poured into aqueous potassium carbonate, and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated and purified by silica gel column chromatography eluting with 20% to 100% ethyl acetate in hexane to give a white solid (529, 1.00 g, 61%).

Provenance & Evidence