Hydrochloric Acid → 4-(piperazin-1-yl)-1H-indole

Participants

Reaction Steps

A suspension of 4-aminoindole (2.30 g, 0.017 moles), bischloroethylamine hydrochloride (3.49 g, 0.02 moles) and potassium carbonate (5.41 g, 0.02 moles) in butanol (50 ml) was heated at reflux under argon for 7 h. Further bischloroethylamine hydrochloride (0.70 g, 0.04 moles) and potassium carbonate (1.1 g 0.04 moles) was added, then the suspension was heated at reflux for 18 h. The solvent was evaporated in vacuo to give a brown gummy residue which was taken up into dilute hydrochloric acid (200 ml), washed with ethyl acetate (2×100 ml), made basic with potassium carbonate, extracted into dichloromethane (3×50 ml), dried (MgSO4) then evaporated in vacuo to give a white solid which was triturated with ethyl acetate and dried to give 4-(1-piperazinyl)indole (0.78 g, 0.0038 moles) as white crystals.

Provenance & Evidence