NaH (78 mg, 1.95 mmol, 60% w/w oil solution) was slowly added to a solution of 4-chloro-3H-imidazo[4,5-c]pyridine (100 mg, 0.65 mmol) in DMF (3 mL) at 0 °C under nitrogen protection. The reaction mixture was stirred at 0 °C for 40 min. Subsequently, iodomethane (277 mg, 1.95 mmol) was added at the same temperature. The reaction mixture was warmed to room temperature and stirring was continued for 2 hours. Upon completion of the reaction, the reaction was quenched with saturated aqueous NH4Cl solution and extracted with ethyl acetate (20 mL x 3). The organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by preparative HPLC to afford 4-chloro-1-methyl-1H-imidazo[4,5-c]pyridine (58, 40.3 mg) and 4-chloro-3-methyl-3H-imidazo[4,5-c]pyridine (59, 41.0 mg), both yellow oils, respectively.LRMS (m/z): [M+H]+ calculated values 168.2, 170.2; measured values 168.0, 170.2.