General procedure for the synthesis of 5-chloro-1H-pyrrolo[3,2-B]pyridine from compound (CAS:1420070-26-3): 5-chloro-1H-pyrrolo[3,2-B]pyridine (1.01 g, 5.1 mmol) was dissolved in 20 mL of methanol. 1 mL of concentrated hydrochloric acid was added and the reaction mixture was stirred at 75 °C for 21 hours. After completion of the reaction, the solvent was removed by evaporation under reduced pressure and the residue was extracted by partitioning with saturated potassium carbonate solution and ethyl acetate. The organic layer was dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. Purification by fast column chromatography (eluent: ethyl acetate/hexane, 33:67, v/v) afforded 0.55 g (3.6 mmol, 71% yield) of the target product, 5-chloro-1H-pyrrolo[3,2-B]pyridine, as a light yellow solid with 95% purity.1H NMR (300 MHz, CDCl3 + DMSO-d6) δ 9.85 (br. s , 1H), 7.67 (d, J = 8.5 Hz, 1H), 7.47 (m, 1H), 7.10 (d, J = 8.5 Hz, 1H), 6.65 (m, 1H).HPLC/MS analysis (run time 9 min) showed a retention time of 4.27 min. Low resolution mass spectrometry (LRMS): m/z 153 ([M + H]+).