1: 4-bromo-1-phenyl-5-trifluoromethyl-1H-pyrazole With n-butyllithium; N,N,N',N'',N''-pentamethyldiethylenetriamine; diisopropylamine in tetrahydrofuran; hexane T=-75°C; 0.0833333 h; 2: carbon dioxide Further stages.;

1.1: ethanol / 2 h / Heating 1.2: 78 percent / cc. HCl / CH2Cl2 / 1 h / 25 °C 2.1: 52 percent / diisopropylamine; N,N,N',N",N"-pentamethyldiethylenetriamine; butyllithium / tetrahydrofuran; hexane / 0.08 h / -75 °C 3.1: 14 percent / diisopropylamine; N,N,N',N",N"-pentamethyldiethylenetriamine; butyllithium / tetrahydrofuran; hexane / 0.08 h / -75 °C View Scheme

1: 52 percent / diisopropylamine; N,N,N',N",N"-pentamethyldiethylenetriamine; butyllithium / tetrahydrofuran; hexane / 0.08 h / -75 °C 2: 14 percent / diisopropylamine; N,N,N',N",N"-pentamethyldiethylenetriamine; butyllithium / tetrahydrofuran; hexane / 0.08 h / -75 °C View Scheme