反応 #930306

反応方程式

3-cyclopropyl-4-hydroxy-benzofuran-2-carboxylic acid ethyl ester

potassium carbonate

1,3-dibromopropane

→

4-(3-bromo-propoxy)-3-cyclopropyl-benzofuran-2-carboxylic acid ethyl ester

溶媒

N,N-dimethylformamide

反応条件

後処理

1. 1
   その他The reaction was quenched with saturated aqueous ammonium chloride solution (5 ml)
2. 2
   workup.ADDITIONdiluted with ethyl acetate (8 ml)
3. 3
   洗浄The organic layer was washed with water (5 ml twice) and brine
4. 4
   乾燥dried over anhydrous sodium sulfate
5. 5
   濃縮concentrated in vacuo to dryness
6. 6
   その他The residue was purified by silica gel column chromatography

実験手順

To a mixture of 3-cyclopropyl-4-hydroxy-benzofuran-2-carboxylic acid ethyl ester (92 mg) and potassium carbonate (62 mg) in N,N-dimethylformamide (1.5 ml) was added 1,3-dibromopropane (190 μl) and the reaction mixture was stirred for 2 hours at room temperature. The reaction was quenched with saturated aqueous ammonium chloride solution (5 ml) and diluted with ethyl acetate (8 ml). The organic layer was washed with water (5 ml twice) and brine, dried over anhydrous sodium sulfate, then concentrated in vacuo to dryness. The residue was purified by silica gel column chromatography developed by hexane-ethyl acetate to give 4-(3-bromo-propoxy)-3-cyclopropyl-benzofuran-2-carboxylic acid ethyl ester (120 mg) as a white solid. EI-MS: m/z 368 (M+); 1H-NMR (CDCl3): δ 0.91-0.95 (4H, m), 1.37 (3H, t, J=7.26 Hz), 2.36 (2H, quintet, J=7.26 Hz), 2.47-2.51 (1H, m), 3.60 (2H, t, J=7.26 Hz), 4.16 (2H, t, J=7.26 Hz), 4.37 (2H, q, J=7.26 Hz), 6.58 (1H, d, J=8.25 Hz), 7.07 (1H, d, J=8.25 Hz), 7.24 (1H, dd, J=8.25 Hz, 8.25 Hz).

出典