1: 4-bromo-1-methyl-5-(trifluoromethyl)pyrazole With tert.-butyl lithium in diethyl ether; pentane T=-75°C; 0.0833333 h; 2: carbon dioxide Further stages.;

1: 1-methyl-5-(trifluoromethyl)pyrazole With lithium diisopropyl amide in tetrahydrofuran; hexane T=-75°C; 0.75 h; 2: carbon dioxide Further stages.;

1: 67 percent / bromine; iron powder / 1 h / 100 °C 2: 88 percent / tert-butyllithium / pentane; diethyl ether / 0.08 h / -75 °C View Scheme