3,3,5-Tribromo-1H-pyrrolo[2,3-b]pyridin-2(3H)-one → 5-bromo-1H,2H,3H-pyrrolo(2,3-b)pyridin-2-one

Participants

Reaction Steps

Under argon at room temperature, 17.60 g (0.27 mol) of powdered zinc are added in portions to 5 g (13.5 mmol) of the compound obtained in Step A dissolved in 100 ml of acetic acid. After 15 hours' stirring at room temperature, the acetic acid is removed by evaporation under reduced pressure (coevaporation with toluene). The residue, which is taken up in ethyl acetate, is washed once with water: the aqueous phase is washed several times with ethyl acetate. The organic phases are combined, dried over magnesium sulphate, concentrated and purified by flash chromatography over silica gel (eluant:dichloromethane/methanol, 95/5), to obtain the title compound in the form of an orange solid.

Provenance & Evidence