Acetic Acid → 6-(Trifluoromethyl)indole

Participants

Reaction Steps

The commercially available (2-nitro-4-trifluoromethylphenyl) acetonitrile (14.0 g, 60.8 mmol) was dissolved in 9:1 EtOH:H2O (50 mL) and glacial acetic acid (1.4 mL). This mixture was hydrogenated over 10% Pd/C (5.0 g) at 50 psi for 16 h at room temperature. The reaction was filtered over celite and evaporated in vacuo. The residue was partitioned between saturated aqueous sodium carbonate and dichloromethane (2×200 mL) and the combined organic extract was dried over sodium sulfate, filtered, and concentrated in vacuo. The crude material was purified by silica gel column chromatography (hexanes/ethyl acetate, 20:1, 9:1, 5:1) to afford 12.9 g (65% yield) of 6-trifluoromethyl-1H-indole as a yellow solid: 1H NMR (400 MHz, CDCl3) 8.36, (1H, br s), 7.72 (2H, m), 7.37 (2H, m), 6.63 (1H, m); MS m/e 184 (M−H)−. Anal calcd. for C9H6F3N: C, 58.38; H, 3.26; N, 7.56. Found: C, 58.30; H, 2.92; N, 7.49.

Provenance & Evidence