N([O-])=O.[Na+].[Br:5][C:6]1[C:12]([C:13]([F:16])([F:15])[F:14])=[CH:11][CH:10]=[CH:9][C:7]=1N.OS(O)(=O)=O.[I:22]I.[O-]S([O-])=O.[Na+].[Na+]>O>[Br:5][C:6]1[C:12]([C:13]([F:16])([F:15])[F:14])=[CH:11][CH:10]=[CH:9][C:7]=1[I:22]An ice-cold solution of NaNO2 (0.15 g) in water (0.5 mL) is added to a mixture of 2-bromo-3-trifluoromethyl-aniline (0.48 g), concentrated H2SO4 (2 mL), and water (1.8 mL) at ca. 5° C. The mixture is stirred in the cooling bath for 20 min and then poured into a solution of KI (0.56 g) and I2 (0.56 g) in water (0.5 mL). After ceasing of gas evolution, the mixture is heated to 40° C. and stirred at this temperature for 1 h. The mixture is cooled to room temperature and aqueous Na2SO3 solution is added. The resulting mixture is extracted with ethyl acetate and the combined extracts are dried (Na2SO4) and concentrated. The solvent is evaporated and the residue is chromatographed (cyclohexane/ethyl acetate 95:5→90:10) to give the title compound.
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