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

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Reaction Steps

To a solution of 6-methoxy-1-methyl-2-trifluoromethyl-1H-indole-3-carboxylic acid ethyl ester 76e (1.5 g, 4.98 mmole) in 10 ml THF and 5 ml MeOH was added a solution of KOH (2.8 g, 50 mmole) in 5 ml water with ice bath cooling. The mixture was warmed to room temperature and stirred overnight. Concentrated aqueous HCl solution was added to adjust the pH to 1. The mixture was extracted with EtOAc and the combined organic layer was dried over Na2SO4, filtered and concentrated. The residue was further purified by column chromatography (eluting with 1-5% MeOH in CH2Cl2) to give 880 mg product (65% yield). 1H NMR (300 MHz, CD3OD) δ7.90 (1H, d, J=9.0 Hz), 7.01 (1H, d, J=2.1 Hz), 6.91 (1H, dd, J=2.1, 9.0 Hz), 3.90 (3H, s), 3.88 (3H, s).

Provenance & Evidence