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

5470-18-8

1826-67-1

357263-41-3

The general procedure for the synthesis of 7-chloro-1H-pyrrolo[2,3-c]pyridine from 2-chloro-3-nitropyridine and vinylmagnesium bromide was as follows: 2-chloro-3-nitropyridine (10.0 g, 63.07 mmol) was dissolved in 500 mL of anhydrous tetrahydrofuran (THF) and magnetically stirred at -78 °C. An excess of vinylmagnesium bromide (1 M THF solution, 200 mL, 200.0 mmol) was added slowly dropwise, and after completion of the dropwise addition, the reaction mixture was slowly warmed to -20 °C and kept for 16 hours. Subsequently, saturated aqueous ammonium chloride solution (300 g/L, 150 mL, 841.25 mmol) was added dropwise under vigorous stirring to quench the reaction. The resulting suspension was filtered through Hyflo Super Cel filter aid (pre-calcined treatment) and extracted with ethyl acetate (EtOAc, 3×). The organic phases were combined and concentrated, and finally purified by automated fast column chromatography (eluent: dichloromethane/methanol, 97:3, followed by dichloromethane/methanol/ammonium hydroxide, 980:18.75:1.25) to afford the pure product, 7-chloro-1H-pyrrolo[2,3-c]pyridine (3.87 g, 38% yield). The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 8.73 (s, 1H), 8.04 (d, J = 5.5 Hz, 1H), 7.53-7.46 (m, 1H), 7.43 (dd, J = 6.2, 3.4 Hz, 1H), 6.64 (dd, J = 3.1, 2.1 Hz, 1H).