Hydrochloric Acid → 5-Methoxy-3-methyl-6-trifluoromethyl-1H-indole-2-carboxylic acid

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Reaction Steps

5-Methoxy-3-methyl-6-trifluoromethyl-1H-indole-2-carboxylic acid ethyl ester (3.0 g, 10 mmol) was dissolved in 10 ml absolute ethanol, and a solution of KOH (1.7 g, 30 mmol) in 7 ml water was added. The reaction mixture was heated to reflux for 2.5 hours, then cooled, acidified slowly with 6 N HCl to pH=2, and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate, filtered, and concentrated under reduced pressure to give 2.0 g, (73%) 5-Methoxy-3-methyl-6-trifluoromethyl-1H-indole-2-carboxylic acid.

Provenance & Evidence