反应详情

To a solution of 6-amino-5-bromo-2-iodo-N-methylbenzofuran-3-carboxamide (1 g, 2.53 mmol) in pyridine, MsCl (580 mg, 5.06 mmol) was added dropwise at 0° C. The mixture was allowed to warm to room temperature and stirred for 1.5 h. After the solvent was removed in vacuo, the reaction mixture was adjusted to pH=5-6 with 1 N HCl aq. After filtration, the solid was dissolved in THF:H2O=5:1 (15 mL) and then LiOH.H2O (800 mg, 20 mmol) was added. The mixture was stirred for 30 minutes at room temperature. After the solvent was removed in vacuo, the reaction mixture was adjusted to pH=5-6 with 1 N HCl aq. Finally the precipitate was collected to give 5-bromo-2-iodo-N-methyl-6-(methylsulfonamido)benzofuran-3-carboxamide (800 mg, 90% purity by HPLC, yield: 60%), which was used for the next step without further purification. 1H-NMR (CDCl3, 400 MHz) δ 8.37 (s, 1H), 7.84 (s, 1H), 6.86 (s, 1H), 6.29 (s, 1H), 3.07 (d, J=4.8 Hz, 3H), 2.99 (s, 3H). MS (M+H)+: 473/475.

1. customAfter the solvent was removed in vacuo
2. filtrationAfter filtration
3. dissolutionthe solid was dissolved in THF
4. stirringThe mixture was stirred for 30 minutes at room temperature
5. customAfter the solvent was removed in vacuo
6. customwas collected