Triethylamine → (E)-5-[3-(4-Fluorophenyl)-1-isopropyl-1H-indol-2-yl]-3-methylpenta-2,4-dienoic Acid Methyl Ester

Participants

Reaction Steps

2.0 g of crude 5-[3-(4-fluorophenyl)-1-isopropyl-1H-indol-2-yl]-3-methylhex-2-enoic acid methyl ester in 50 ml of toluene are introduced into a 100 ml three-necked round-bottomed flask, equipped with a magnetic stirrer, thermometer, reflux condenser and nitrogen delivery line, 0.9 g (8.87 mmol) of triethylamine are added and the yellow solution is heated at reflux with stirring. After 2 hours, the reaction mixture is cooled, diluted with 50 ml of toluene, washed once with 100 ml of 1N hydrochloric acid and three times with 50 ml of water and concentrated by evaporation using a rotary evaporator. The crude product (orange oil) is purified by means of flash chromatography (hexane/ethyl acetate=10:1). An orange resin is obtained which, according to NMR, contains approximately 30% (E)-5-[3-(4-fluorophenyl)-1-isopropyl-1H-indol-2-yl]-3-oxopent-4-enoic acid methyl ester (mixture of keto and enol forms).

Provenance & Evidence