反应详情

To a solution of ethyl 6-amino-5-bromo-2-cyclopropylbenzofuran-3-carboxylate (7 g, 22.5 mmol) in 1,4-dioxane and H2O (50 mL and 50 mL) was added LiOH.H2O (4.6 g, 112 mmol). 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 were filtered to give the product of 6-amino-5-bromo-2-cyclopropylbenzofuran-3-carboxylic acid (6.5 g, yield: 97%). 1H-NMR (400 MHz, MeOD) δ 7.86 (s, 1H), 6.85 (s, 1H), 4.31 (s, 2H), 2.93˜3.00 (m, 1H), 1.19˜1.22 (m, 2H), 1.13˜1.16 (m, 2H). MS (M+H)+: 296/298.

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