Trifluoroacetic acid → (1h-Indol-2-yl)-piperazin-1-yl-methanone trifluoroacetate salt

Participants

Reaction Steps

4-(1H-Indole-2-carbonyl)-piperazine-1-carboxylic acid tert-butyl ester (0.165 g) in dichloromethane (10 mL) was treated with trifluoroacetic acid (2 mL) and stirred at ambient temperature for 1 h. The solvent was removed under reduced pressure to afford (1H-Indol-2-yl)-piperazin-1-yl-methanone trifluoroacetate salt. (1H NMR (400 MHz, CDCl3): δ 7.63 (d, J=8.07 Hz, 1H), 7.44 (dd, J=8.3, 0.8 Hz, 1H), 7.24 (m, 1H), 7.08 (m, 1H), 6.91 (s, 1H), 4.12 (t, J=5.0 Hz, 4H), 3.35 (t, J=5.3 Hz, 4H)). This intermediate was dissolved in acetone (5 mL), treated with potassium carbonate (0.22 g), iodohexane (0.106 g) and heated at 50° C. for 10 h. Evaporation of the solvent under reduced pressure afforded crude product which was purified via preparative thin layer chromatography eluting with 10% methanol/dichloromethane to give the title compound (0.06 g). 1H NMR (400 MHz, CD3OD): δ 7.60 (d, J=8.0 Hz, 1H), 7.42 (d, J=8.3 Hz, 1H), 7.21(ddd, J=8.1, 7.1, 1.1 Hz, 1H), 7.16-7.04 (m, 1H), 6.81 (s, 1H), 3.89 (br s, 4H), 2.56 (t, J=5.0 Hz, 4H), 2.43-2.40 (m, 2H), 1.58-1.52 (m, 2H), 1.34 (br s, 6H), 0.94-0.90 (m, 3H).

Provenance & Evidence