5,7-dichloro-1H-pyrrolo[2,3-c]pyridine

16013-85-7

1826-67-1

1001412-41-4

Step A: Synthesis of 5,7-dichloro-1H-pyrrolo[2,3-c]pyridine: 2,6-dichloro-3-nitropyridine (11 g, 56.998 mmol) was dissolved in anhydrous tetrahydrofuran (350 mL) under dry conditions. The solution was cooled to -78 °C and vinylmagnesium bromide (1M THF solution, 199.5 mmol) was added slowly and dropwise. After the dropwise addition was completed, the reaction mixture was slowly warmed to -20 °C and stirred continuously at this temperature for 1 hour. Upon completion of the reaction, the reaction was quenched with 200 mL of saturated aqueous ammonium chloride solution, followed by extraction with ethyl acetate. The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure at 50 °C. Purification was carried out by Combi fast chromatography using a 24 g silica gel column with cyclohexane/ethyl acetate (0-70% gradient) as eluent to afford 5,7-dichloro-6-azaindole as a yellow foamy solid (3.7 g, 35% yield).