Ethyl 6-chloro-4-((2,4-dimethoxybenzyl)amino)nicotinate (15 g, 42.8 mmol) was used as a raw material, which was mixed with trifluoroacetic acid (TFA, 80 mL), heated to 50 °C and the reaction was maintained for 3 hours. Upon completion of the reaction, the mixture was cooled to room temperature and the solvent was subsequently removed under reduced pressure. The pH of the residue was adjusted to 8 with aqueous sodium bicarbonate (NaHCO3) and then extracted with ethyl acetate (EtOAc). The organic layer was washed with saturated saline, dried over anhydrous sodium sulfate (Na2SO4), filtered and concentrated. Finally, the residue was purified by silica gel column chromatography (petroleum ether:ethyl acetate=4:1) to afford the target product ethyl 4-amino-6-chloronicotinate (5.1 g, 61% yield) as a white solid.