Ethylenediamine → 9-bromo-5H-pyrazino[2,3-b]indole

Participants

Reaction Steps

1-Acetyl-4-bromo-1,2-dihydro-indol-3-one (460 mg, 1.81 mmol) was dissolved in CH2Cl2 (8 mL). Bromine (111 μL, 2.2 mmol) was added slowly, and the reaction stirred for 20 min and then was concentrated in vacuo. The residue was dissolved in THF (8 mL). Ethylenediamine (244 μL, 3.6 mmol) was added, and the reaction stirred for 16 h at r.t. Triethylamine (2 mL) and MeOH (4 mL) were added, and the reaction stirred while left open to air for 24 h. The solution was concentrated in vacuo and purified by silica gel chromatography (8% MeOH/CH2Cl2) to provide the title compound as a red solid (248 mg, 55%). MS (ES) [m+H] calc'd for C10H6BrN3, 248, 250; found 248, 250.

Provenance & Evidence