Methanol → 5-Hydroxy-1-(2,2,2-trifluoro-ethyl)-1H-indole-2-carboxylic acid

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Reaction Steps

A mixture of 5-hydroxy-1-(2,2,2-trifluoro-ethyl)-1H-indole-2-carboxylic acid ethyl ester (Intermediate 1, step b, 8.5 g, 1.0 eq.), lithium hydroxide monohydrate (1.43 g, 1.15 eq.), water (45 mL), methanol (30 mL) and tetrahydrofuran (90 mL) was heated to reflux for 24 h. The volatiles were removed in vacuo and the resulting solution was acidified (pH ca. 2) with hydrochloric acid (1N). The precipitate was filtered and dried in vacuo to yield 7.65 g (99%) of the desired product as off-white solid. MS (m/e): 258.5 (M−H−, 100%).

Provenance & Evidence