Water → HCID 22394611, compound

Participants

Reaction Steps

To a solution of 1,4-dimethyl-1H-indole, (200 mg, 1.38 mmol) in tert-butanol (8 mL) was added water (4 mL) and the mixture was put at 50° C. In a separate flask was added potassium bromide (1.6 g, 13.8 mmol) followed by water (11 mL) and bromine (0.36 mL, 6.9 mmol). Next the bromine solution (8 was added dropwise to the 1,4-dimethyl-1H-indole mixture. After the addition was complete the temperature of the reaction was elevated to 70° C. for 30 min. The reaction was cooled to room temperature and diluted with dichloromethane and saturated aqueous sodium bicarbonate. The solution was then further diluted with saturated aqueous sodium thiosulfate. The layers were separated and the aqueous layer was extracted two additional times with dichloromethane. The organic extracts were combined, dried over anhydrous sodium sulfate, filtered and concentrated. The resulting solid was filtrated with diethyl ether and one half of the solid, by weight, was then dissolved in acetic acid (2.5 Zinc dust (62 mg, 0.94 mmol) was then added. After 10 minutes the reaction mixture was filtered through a pad of Celite® and diluted with dichloromethane. The resulting solution was cooled to 0° C. and neutralized via the cautious addition of 2 N aqueous sodium hydroxide and saturated aqueous sodium bicarbonate. The resulting layers were separated and the aqueous layer was extracted two additional times with dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated. The resulting residue was purified by silica gel flash chromatography (ethyl acetate-heptane 15 to 80%) to afford 5-bromo-1,4-dimethyl-1,3-dihydro-indol-2-one; 1H NMR (400 MHz, CDCl3) δ ppm 2.32 (s, 3H), 3.19 (s, 3H), 3.47 (s, 2H), 6.56 (d, J=8.1 Hz, 1H), 7.48 (d, J=8.1 Hz, 1H).

Provenance & Evidence