BrBr.[OH-:3].[Na+].[Br:5][C:6]1[CH:11]=[C:10]([O:12][CH3:13])[CH:9]=[CH:8][C:7]=1[C:14](=[O:16])C>OS([O-])=O.[Na+]>[Br:5][C:6]1[CH:11]=[C:10]([O:12][CH3:13])[CH:9]=[CH:8][C:7]=1[C:14]([OH:16])=[O:3]Br2 (8.5 mL, 165.89 mmol) is added dropwise to 20% NaOH (97 mL) at 0-10° C. in a 15-min period. The resulting solution is warmed to room temperature before 1-(2-bromo-4-methoxyphenyl)ethanone (2) (9.50 g, 41.47 mmol) is added. The mixture is stirred at 36° C. for 29 h and at room temperature for 17 h, diluted with 0.5 M NaHSO3 (25 mL), and extracted with ether (100 mL and 70 mL). The aqueous layer is acidified with conc. HCl (30 mL) to give 6.56 g (68%) of 3 as a white solid, mp 195-197° C. IR 2997, 1686, 1596, 1290 cm−1; 1H NMR (CDCl3) δ 3.80 (s, 3H, CH3O), 6.83 (dd, J=7.2, 2.0 Hz, 1H, 5-PhH), 7.15 (d, J=2.0 Hz, 1H, 3PhrH), 7.90 ppm (d, J=7.2 Hz, 1H, 6-PhH).
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