[CH2:1]([C:3]1[O:7][C:6]([C:8]([O:10][CH3:11])=[O:9])=[CH:5][CH:4]=1)[CH3:2].[Cl-].[Cl-].[Cl-].[Al+3].[Br:16]Br>C(Cl)(Cl)Cl>[Br:16][C:4]1[CH:5]=[C:6]([C:8]([O:10][CH3:11])=[O:9])[O:7][C:3]=1[CH2:1][CH3:2]To a solution of methyl 5-ethyl-2-furancarboxylate (1.2 g, 7.78 mmol) and aluminum trichloride (1.56 g, 11.68 mmol) in chloroform (15 ml) at 25° C. was added bromine (0.56 ml, 10.90 mmol). The resulting solution stirred at 70° C. in a sealed tube for 2 h and the solution was cooled, concentrated and purified via column chromatography (silica, 5% EtOAc in hexanes) affording methyl 4-bromo-5-ethyl-2-furancarboxylate (1.1 g, 3.26 mmol, 41.8% yield) as a white solid; LCMS (ES) m/z=233, 235 (M, M+2)+.
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