1H-Imidazo[4,5-c]pyridine, 4-chloro-7-fluoro- (9CI)

122-51-0

405230-93-5

405230-97-9

General procedure for the synthesis of 4-chloro-7-fluoro-1H-imidazo[4,5-c]pyridines from triethyl orthoformate and 2-chloro-3,4-diamino-5-fluoropyridine: sulfamic acid (187 mL, 4.15 mmol) was added to a solution of 2-chloro-5-fluoropyridine-3,4-diamine (670 mg, 4.15 mmol, commercially available from Bellen, Inc. Beijing, China) and triethyl orthoformate (2.76 mL, 16.6 mmol) in a solution of methanol (10 mL). The mixture was heated to reflux for 16 hours. After completion of the reaction, the mixture was cooled to room temperature, diluted with saturated aqueous NaHCO3 solution and extracted with dichloromethane (DCM). The DCM extracts were combined, washed with brine, dried over anhydrous Na2SO4, filtered and concentrated in vacuum. The residue was purified by silica gel column chromatography using a gradient elution of 0-20% methanol/DCM to afford the target product 4-chloro-7-fluoro-1H-imidazo[4,5-c]pyridine (560 mg, 3.26 mmol, 79% yield).