2-Bromobutane → Methyl 6-bromo-1-(sec-butyl)-1H-indole-4-carboxylate

関与物質

反応手順

To a stirred suspension of sodium hydride (5.66 g, 141.7 mmol) in DMF (100 mL) was added a solution of methyl 6-bromo-1H-indole-4-carboxylate (4) (30 g, 118.1 mmol) in DMF (50 mL) at 0° C. and stirred for 20 min. Then 2-Bromo butane (29.1 g, 212.5 mmol) was added at 0° C. and the reaction mixture was stirred at room temperature for 16 h. The reaction mixture was diluted with cold water and extracted with ethyl acetate (4×150 mL). The combined organic layer was washed with cold water (150 mL), brine (100 mL) and dried over anhydrous Na2SO4 and concentrated under reduced pressure to afford crude, which was purified by column chromatography over silica gel (60-120 mesh) using 5% EtOAc: Pet ether as eluent to afford the title compound methyl 6-bromo-1-sec-butyl-1H-indole-4-carboxylate, (14 g, 40.1%) as pale yellow solid. 1H NMR (CDCl3, 400 MHz) δ 0.843-0.870 (m, 3H), 1.512 (d, J=6.4 Hz, 3H), 1.844-1.926 (m, 2H), 3.976 (s, 3H), 4.333-4.385 (m, 1H), 7.132 (d, J=3.2 Hz, 1H), 7.302 (d, J=3.6 Hz, 1H), 7.707 (s, 1H), 7.984 (d, J=1.6 Hz, 1H).

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