Hydrochloric Acid → 4,7-Dibromo-1H-indole

Participants

Reaction Conditions

Reaction Steps

To a solution of 1,4-dibromo-2-nitrobenzene (18 g, 64.1 mmol) in THF (200 mL) at −40° C. (dry ice-acetonitrile) was added slowly a solution of vinylmagnesium bromide (1.0 M in THF, 199 mL, 199 mmol). The resulting mixture was stirred at −40° C. for 1.5 h, then was then treated with saturated aqueous NH4Cl (500 mL) and stirred at room temperature for 1 h. HCl (1M) was added to adjust the pH to 7. EtOAc was added and the organic phase was separated, washed with brine, dried and concentrated. The residue was subjected to column chromatography on silica gel (330 g), eluting with EtOAc-hexane (5:95) to provide a light yellow oil which solidified on standing under vacuum. The desired product was obtained as a solid (8.35 g, 47% yield. LCMS showed one major peak with no ionization.

Provenance & Evidence