C[Si](C=[N+]=[N-])(C)C.[Br:8][C:9]1[C:17]([CH3:18])=[CH:16][C:12]([C:13]([OH:15])=[O:14])=[C:11]([F:19])[CH:10]=1.[CH3:20]O>C1C=CC=CC=1>[Br:8][C:9]1[C:17]([CH3:18])=[CH:16][C:12]([C:13]([O:15][CH3:20])=[O:14])=[C:11]([F:19])[CH:10]=1(Trimethylsilyl)diazomethane (4.0 ml, 8.0 mmol, 2 M in Et2O) was added dropwise to a solution of 4-bromo-2-fluoro-5-methyl-benzoic acid (1.88 g, 8.05 mmol) in benzene (7.5 ml)-MeOH (5.6 ml) at 10±2° C. over 10 minutes. The mixture was stirred at room temperature for 30 minutes and then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane/ethyl acetate=40/1) to give methyl 4-bromo-2-fluoro-5-methyl-benzoate (1.62 g, 82%).
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