N-bromobutanimide → 4-bromo-1-pentyl-1H-indole-2,3-dione

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-bromo-1-pentyl-1H-indole (25.0 g, 93.9 mmol) in anhydrous dimethylsulfoxide (350 mL) was added N-bromosuccinimide (50.2 g, 282 mmol) in portions over 30 min. The reaction mixture was heated at 60° C. for 3 h, upon which time the internal temperature increased to 120° C. After cooling down to ambient temperature, the reaction mixture was poured onto ethyl acetate/water (1/1, 600 mL). The organic layer was separated and the aqueous layer was extracted with ethyl acetate (3×500 mL). The combined organic layers was washed with water (3×500 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to dryness to yield the title compound (25.7 g, 92%) as a yellow solid: 1H NMR (300 MHz, CDCl3) δ 7.38 (t, 1H), 7.21 (t, 1H), 6.82 (d, 1H), 3.68 (t, 2H), 1.72-1.59 (m, 2H), 1.39-1.25 (m, 4H), 0.86 (t, 3H); 13C NMR (75 MHz, CDCl3) δ 180.9, 157.2, 152.6, 138.4, 128.3, 121.7, 116.3, 108.9, 40.4, 28.9, 26.9, 22.3, 13.9.

Provenance & Evidence