4-bromo-1H-pyrrolo[2,3-c]pyridine

Synthesis

2-(3-bromo-5-nitropyridin-4-yl)-N, N-dimethylethylenamine (2.38 g, 8.78 mmol) and iron powder (~325 mesh, 2.45 g, 43.9 mmol) were stirred in acetic acid (25 mL). The red mixture was heated to reflux and turned grayish-green with a white precipitate. After refluxing for 45 min, the reaction was cooled, diluted with EtOAc (150 mL), filtered through Celite and rinsed with additional EtOAc. The filtrate was slowly basified to pH 8 with saturated aqueous NaHCO3, and the aqueous layer was extracted with EtOAc. The combined organics were washed with brine, dried (MgSO4), filtered, and concentrated in vacuo. Silica gel chromatography (eluding with 5% MeOH in EtOAc) afforded 4-bromo-1H-pyrrolo[2,3-c]pyridine (1.26 g, 73%) as a yellow solid.