Indole → 1-(3,5-Dichlorophenyl)-1H-indole

Participants

Reaction Steps

A mixture of 5 g (43.7 mmol) of indole, 19.2 g (85.3 mmol) of 1-bromo-3,5-dichlorobenzene, 11.7 g (84.8 mmol) of potassium carbonate and 3.28 g (1.22 mmol) of copper powder in 14 mL of 1,2-dichlorobenzene was warmed at reflux. After 24 h, the mixture was cooled and diluted with dichloromethane and filtered through diatomaceous earth. The filter cake was washed with a 1:9 mixture of methanol-dichloromethane. The filtrate was pre-adsorbed onto silica gel and chromatographed on silica gel eluting with hexane. The partially purified material was placed under high vacuum to remove excess 1,2-dichlorobenzene and sublime excess 1-bromo-3,5-dichlorobenzene. A second chromatography on silica gel eluting with hexanes afforded 7.8 g (70%) of 1-(3,5-Dichlorophenyl)-1H-indole.

Provenance & Evidence