1: 4-bromo-1-methyl-3-(trifluoromethyl)pyrazole With n-butyllithium; diisopropylamine in tetrahydrofuran; hexane T=-75°C; 0.0833333 h; 2: carbon dioxide Further stages.;

1: 65 percent / bromine; iron powder / 4 h / 100 °C 2: 90 percent / diisopropylamine; butyllithium / tetrahydrofuran; hexane / 0.08 h / -75 °C View Scheme