1: 4-bromo-3-trifluoromethyl-1,5-dimethylpyrazole With tert.-butyl lithium in tetrahydrofuran; pentane T=-78°C; 0.05 h; 2: N,N-dimethyl-formamide in tetrahydrofuran; pentane T=-78 - 0°C; 2 h; 3: With hydrogenchloride; water in tetrahydrofuran; pentane T=20°C; 1 h;