131084-55-4

1167056-96-3

Bromine (Br2) (0.68 mL, 13.3 mmol) was added dropwise to a stirred solution of 5-chloro-1H-pyrrolo[2,3-c]pyridine (2.0 g, 13.3 mmol) in anhydrous N,N-dimethylformamide (DMF) (80 mL) at room temperature. The reaction mixture was stirred continuously for 1 hour at room temperature. Upon completion of the reaction, the reaction was quenched with 10% sodium thiosulfate (Na2S2O3) solution (100 mL) and diluted with deionized water (H2O) (400 mL). The aqueous phase was extracted with ethyl acetate (EtOAc) (100 mL × 4), and the organic phases were combined and washed with deionized water (50 mL × 3) and saturated saline (50 mL × 3) sequentially. The organic layer was dried over anhydrous sodium sulfate (Na2SO4), concentrated under reduced pressure and dried under vacuum to obtain 3-bromo-5-chloro-1H-pyrrolo[2,3-c]pyridine (2.9 g, 95% yield). Liquid chromatography-mass spectrometry (LCMS) (electrospray ionization, ESI) analysis: the calculated value of C7H4BrClN2 [M+H]+ was 231 and the measured value was 231.