反应详情

To a solution of ethyl 6-amino-5-bromobenzofuran-3-carboxylate (58 g, 204 mmol) in 1,4-dioxane and H2O (850 mL and 150 mL) was add LiOH.H2O (42.8 g, 1.02 mol). The reaction mixture was refluxed for 2 hours, and then 400 mL H2O was added to the reaction mixture. After acidifying to pH 4˜5 with HCl, the resulting solid was filtered to give the product of 6-amino-5-bromobenzofuran-3-carboxylic acid (51 g, yield: 97%). 1H-NMR (DMSO-d6, 400 MHz) δ 8.36 (s, 1H), 7.87 (s, 1H), 7.02 (s, 1H), 5.51 (br s, 2H). MS (M+H)+: 256/258.

1. temperatureThe reaction mixture was refluxed for 2 hours
2. filtrationthe resulting solid was filtered