Trifluoroacetic acid → 5-cyclopropyl-2-phenyl-1H-indole

Participants

Reaction Steps

To a solution of tert-butyl[4-cyclopropyl-2-(2-oxo-2-phenylethyl)phenyl]carbamate (561 mg) in dichloromethane (8 mL) was added dropwise trifluoroacetic acid (1.6 mL) under ice-cooling. The mixture was heated to room temperature, and then stirred for 23 hours. The reaction mixture was concentrated under reduced pressure. To the residue were added ethyl acetate and saturated aqueous sodium hydrogen carbonate solution to separate the organic layer. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluting solvent: ethyl acetate-hexane) to obtain the title compound (317 mg). 1H-NMR (CDCl3) δ ppm: 0.65-0.75 (2H, m), 0.85-1.00 (2H, m), 1.95-2.10 (1H, m), 6.70-6.80 (1H, m), 6.90-7.00 (1H, m), 7.25-7.50 (5H, m), 7.60-7.70 (2H, m), 8.24 (1H, br s).

Provenance & Evidence