Boron tribromide → 4-nitro-1H-indol-5-ol

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Reaction Steps

A solution of 5-methoxy-4-nitroindole (110 mg, 0.57 mmol) in dichloromethane (12 ml) was cooled to −30° C. under an atmosphere of nitrogen. Boron tribromide (0.74 ml of a 1M solution in dichloromethane, 0.74 mmol) was added dropwise then the mixture warmed to ambient temperature and stirred for 1 hour. The mixture was cooled to 5° C., diluted with dichloromethane (5 ml), and water (10 ml). After stirring for 5 minutes the insoluble material was filtered off and the dichloromethane layer separated, dried (MgSO4), and evaporated to give a dark oil which was and purified by silica column chromatography eluting with dichloromethane to give 5-hydroxy-4-nitroindole (68 mg, 67%).

Provenance & Evidence