5-Chloro-6-fluoro-1H-indole-2-carboxylic acid → 5-chloro-6-fluoro-1H-indole

Participants

Reaction Steps

A suspension of 1.92 g of an almost 1:1 mixture of 5-chloro-6-fluoro-indole-2-carboxylic acid and 7-chloro-6-fluoro-indole-2-carboxylic acid in 45 ml of diphenyl ether was stirred at 260° for 4 hours. The reaction mixture was chromatographed over 100 g of silica gel with hexane and hexane-toluene (3:1). There were obtained 0.6 g (39%) of 5-chloro-6-fluoroindole as light brown crystals with m.p. 88°-90° and 0.22 g (14%) of 7-chloro-6-fluoroindole as a dark brown oil.

Provenance & Evidence