[F:1][CH2:2][C:3]([CH3:8])([CH3:7])[C:4](=[O:6])[CH3:5].[Br:9]Br.N1C=NC=N1.C(=O)([O-])[O-].[K+].[K+]>C(Cl)Cl.CC(C)=O>[F:1][CH2:2][C:3]([CH3:8])([CH3:7])[C:4](=[O:6])[CH2:5][Br:9]4.18 kg (35.4 mol) of 1-fluoro-2,2-dimethyl-butan-3-one were dissolved in 30 liters of methylene chloride, and 5.67 kg of bromine were added dropwise at 20° C. in the course of 2 hours such that continuous decolorisation occurred. The solvent was distilled off under a waterpump vacuum, a further 15 liters of methylene chloride were added to the residue and the solvent was again distilled off under a waterpump vacuum. The crude 1-fluoro-4-bromo-2,2-dimethyl-butan-3-one (6.97 kg, quantitative yield) was added dropwise to 2.45 kg of 1,2,4-triazole and 4.89 kg of potassium carbonate in 21.4 liters of acetone at 30° to 35° C. in the course of 2 hours, whilst cooling. The mixture was subsequently stirred at room temperature for 15 hours, the insoluble material was filtered off and the solvent was distilled off from the filtrate under a waterpump vacuum. 6.12 kg (93% of theory) of 1-fluoro-2,2-dimethyl-4-(1,2,4-triazol-1-yl)-butan-3-one, which could be further reacted directly, were obtained.
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