2-Methyl-2-butene → 6-chloro-5-[4-(2-hydroxyethyl)phenyl]-1H-indole-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a mixture of 6-chloro-5-[4-(2-hydroxyethyl)phenyl]-1H-indole-3-carbaldehyde (150 mg, 0.50 mmol) in acetonitrile (5 mL) and tert-butanol (5 mL) was added 2-methyl-2-butene (5 mL). The reaction mixture was cooled to 0° C. and treated with a solution of sodium chlorite (900 mg, 10.0 mmol) and sodium phosphate monobasic hydrate (1.4 g, 10 mmol) in water (5 mL) dropwise via additional funnel. Then ice bath was removed, and the reaction was stirred at room temperature for 20 hours. The solvent was removed in vacuo to give a residue, which was purified by pre-HPLC (Kromasil Eternity-5-C18 150×30 mm×5 μm Mobile phase: from 26% MeCN in water (0.1% TFA) to 41% MeCN in water (0.1% TFA); Wavelength: 220 nm Flow rate: 30 mL/min) to give 6-chloro-5-[4-(2-hydroxyethyl)phenyl]-1H-indole-3-carboxylic acid (35 mg, 25% yield) as a white solid. MS (ES+) 337.9 (M+Na)+. 1H NMR (400 MHz, CD3OD) δ 8.01-7.99 (m, 2 H), 7.57 (s, 1 H), 7.37 (d, 2 H), 7.30 (d, 2 H), 3.80 (t, 2 H), 2.91 (t, 2 H).

Provenance & Evidence