Trifluoroacetic acid → 4-Chloro-2-methyl-1H-indole

Participants

Reaction Steps

To a solution of the crude [3-Chloro-2-(2-oxo-propyl)-phenyl]-carbamic acid tert-butyl ester (5.21 g) in dichloromethane (180 ml) was added trifluoroacetic acid (20 ml). The reaction mixture was stirred at room temperature for 5 days and then partitioned between dichloromethane and 5% sodium bicarbonate solution. The organic extract was washed with brine, dried (anhydrous sodium sulfate), and concentrated under reduced pressure to give 4-Chloro-2-methyl-1H-indole and 3-Chloro-2-methyl-phenylamine as a mixture (2.6 g mixture, 69% yield of 4-Chloro-2-methyl-1H-indole). 1H NMR (CDCl3) d: 2.45 (s, 3H), 6.32-6.33 (m, 1H), 6.98-7.18 (m, 3H), 7.96 (bs, 1H), M−H: 164.

Provenance & Evidence