General procedure for the preparation of 35: 6-chloro-2,3-dihydro-1H-pyrrolo[3,2-c]pyridine: 6-chloro-5-azaindole (500 mg, 3.29 mmol) was dissolved in a THF solution (6.6 mL, 13.16 mmol) of 2.0 M BH3-SMe2 under nitrogen protection. The reaction mixture was slowly heated to 68 °C and maintained for 2 hours. Upon completion of the reaction, it was cooled to room temperature, followed by the slow addition of methanol (6.0 mL) over a period of 20 min. After the gas release stopped, the reaction mixture was again heated to 68 °C and maintained for 30 min, after which it was cooled to room temperature and concentrated under reduced pressure. Purification by silica gel column chromatography (gradient elution, 0-60% ethyl acetate/petroleum ether) afforded 6-chloro-2,3-dihydro-1H-pyrrolo[3,2-c]pyridine (209 mg, 41% yield) as a colorless oil.1H NMR (CDCl3): δ 7.86 (1H, s), 6.43 (1H, s), 4.33 (1H, s), and 3.80-3.65 (2H, m), 3.05 (2H, t).
![6-Chloro-2,3-dihydro-1H-pyrrolo[3,2-c]pyridine](/CAS/GIF/23596-25-0.gif)