[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[S:9][CH:10]=[CH:11][CH:12]=2)=[C:4]([CH3:13])[CH:3]=1.C([O-])(=O)C.[Na+].[Br:19]Br.[OH-].[Na+]>C(O)(=O)C.C(OCC)(=O)C>[Br:19][C:10]1[S:9][C:8]([C:5]2[CH:6]=[CH:7][C:2]([Br:1])=[CH:3][C:4]=2[CH3:13])=[CH:12][CH:11]=1To a stirred homogeneous solution of 2-(4-bromo-2-methylphenyl)thiophene (5.0 mmol, from Step A) and sodium acetate (10 mmol) in acetic acid (25 mL), bromine (5.0 mmol) was added dropwise via syringe at rt over 20-30 min and the resulting mixture was stirred for 1 h. The reaction mixture was combined with 1 M sodium hydroxide (250 mL) and ethyl acetate (250 mL). Organic layer was separated, washed sequentially with 1M sodium hydroxide (100 mL) and brine (100 mL), and dried over sodium sulfate. Silica gel chromatography using hexanes as the eluant afforded the title compound: 1H NMR (CDCl3) 7.46 (d, J=0.6, 1H), 7.38 (dd, J=3.9, 0.6, 1H), 7.24 (d, J=3.9, 1H), 7.09 (d, J=2.9, 1H), 6.83 (d, J=2.9, 1H), 2.43 (s, 3H); HPLC A 4.41 min, ESI-MS (m/z)=334.
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