反应详情

To a solution of 6-hydroxy-benzofuran-4-carboxylic acid methyl ester (6d) (354 mg, 1.82 mmol) in EtOAc was added acetic acid (1 mL) and Pd on carbon (40 mg). The reaction mixture was stirred under hydrogen gas balloon overnight. The mixture was filtered through Celite and concentrated to give a pale yellow solid which was used without further purification. LCMS and NMR showed it was a mixture of 6-hydroxy-benzofuran-4-carboxylic acid methyl ester and 6-hydroxy-2,3-dihydro-benzofuran-4-carboxylic acid methyl ester (2:1). 1H NMR (400 MHz, CDCl3) δ 7.02 (d, J=2.27 Hz, 2 H) 6.53 (d, J=2.27 Hz, 1 H) 4.61 (t, J=8.72 Hz, 2 H) 3.90 (s, 3 H) 3.44 (t, J=8.72 Hz, 2 H).

1. filtrationThe mixture was filtered through Celite
2. concentrationconcentrated
3. customto give a pale yellow solid which
4. customwas used without further purification
5. additiona mixture of 6-hydroxy-benzofuran-4-carboxylic acid methyl ester and 6-hydroxy-2,3-dihydro-benzofuran-4-carboxylic acid methyl ester (2:1)