[Br-:1].[K+].C([O-])(=O)C.[Na+].[CH2:8]([O:10][C:11]([C:13]1[C:14]([C:22]([F:25])([F:24])[F:23])=[N:15][C:16]2[N:17]([CH:19]=[CH:20][N:21]=2)[CH:18]=1)=[O:12])[CH3:9].BrBr.S(=O)(O)[O-].[Na+]>CO>[CH2:8]([O:10][C:11]([C:13]1[C:14]([C:22]([F:24])([F:25])[F:23])=[N:15][C:16]2[N:17]([C:19]([Br:1])=[CH:20][N:21]=2)[CH:18]=1)=[O:12])[CH3:9]Potassium bromide (26.4 mg) and sodium acetate (2.5 eq, 6.6 mmol, 541 mg) were added sequentially to 7-trifluoromehyl-imidazo[1,2-a]pyrimidine-6-carboxylic acid ethyl ester (0.684 g, 2.64 mmol ) in methanol (5.5 mL) and the resulting mixture was stirred at room temperature for 30 minutes. The mixture was then cooled to −5° C. and bromine (1.02 eq, 0.138 mL) was added. Once addition was complete, the reaction was stirred for 1 hour. The mixture was then treated with a saturated aqueous solution of sodium bisulphite and, after stirring for 5 minutes, the solvents were removed under reduced pressure. Water was added to the residue and the pH adjusted with sodium hydroxide until just basic. The resulting solid was collected by filtration, washed with ether and crystallized from hot methanol to afford 3-bromo-7-trifluoromehyl-imidazo[1,2-a]pyrimidine-6-carboxylic acid ethyl ester in quantitative yield. m/z (M+H)=339.2.
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