Boron tribromide → 2-methyl-1H-indol-5-ol

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-methoxy-2-methyl-1H-indole (5 g, 31 mmol) in methylene chloride (100 mL) at −78° C., was slowly added a solution of BBr3 in CH2Cl2 (1.0 M, 93 mL, 93 mmol). The reaction mixture was stirred at −78° C. for 4 hours and slowly warmed to room temperature. The reaction mixture was stirred at room temperature overnight, and cooled to 0° C. The reaction was quenched carefully with water at 0° C. The aqueous layer was made basic by adding saturated sodium bicarbonate solution, and then extracted with methylene chloride (3×50 mL). The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure. The crude product was purified by flash chromatography on silica gel eluting with EtOAc/Hexanes (25:75) to afford the title compound as a yellow solid (3.0 g, 60%).

Provenance & Evidence