1: 3-(trifluoromethyl)-1H-pyrazole; ethyl iodide With potassium carbonate in DMF (N,N-dimethyl-formamide) T=20°C; 2: With n-butyllithium in tetrahydrofuran T=-78°C; 0.333333 h; Cooling with acetone-dry iceNitrogen atmosphere; 3: carbon dioxide With hydrogenchloride more than 3 stages;

1: 1-ethyl-3-(trifluoromethyl)-1H-pyrazole With lithium diisopropyl amide in tetrahydrofuran T=-78°C; 2: carbon dioxide in tetrahydrofuran