[CH3:1][S:2](Cl)(=[O:4])=[O:3].[NH2:6][C:7]1[C:27]([Br:28])=[CH:26][C:10]2[C:11]([C:21]([O:23][CH2:24][CH3:25])=[O:22])=[C:12]([C:14]3[CH:19]=[CH:18][C:17]([F:20])=[CH:16][CH:15]=3)[O:13][C:9]=2[CH:8]=1.N1C=CC=CC=1>ClCCl.O>[Br:28][C:27]1[C:7]([NH:6][S:2]([CH3:1])(=[O:4])=[O:3])=[CH:8][C:9]2[O:13][C:12]([C:14]3[CH:19]=[CH:18][C:17]([F:20])=[CH:16][CH:15]=3)=[C:11]([C:21]([O:23][CH2:24][CH3:25])=[O:22])[C:10]=2[CH:26]=1MsCl (31.7 g, 277.5 mmol) was added to a solution of ethyl 6-amino-5-bromo-2-(4-fluorophenyl)benzofuran-3-carboxylate (35 g, 92.5 mmol) and pyridine (60 mL) in dichloromethane (300 mL) at 0° C. After stirred overnight at room temperature, the mixture was diluted with water and extracted with dichloromethane. The organic layer was washed with brine, dried over Na2SO4, filtered and concentrated in vacuo, the resulting residue was purified using crystallized with EtOAc to provide the pure product of ethyl 5-bromo-2-(4-fluorophenyl)-6-(methylsulfonamido)benzofuran-3-carboxylate (35 g, yield: 82%). 1H-NMR (CDCl3, 400 MHz) δ 8.27 (s, 1H), 8.01˜8.05 (m, 2H), 7.87 (s, 1H), 7.15˜7.19 (m, 2H), 6.87 (s, 1H), 4.38˜4.43 (m, 2H), 3.00 (s, 3H), 1.40 (t, J=40 Hz, 3H). MS (M+H)+: 456/458.
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