General procedure: 2,3-dichloronitrobenzene 488g (2.51mol), methanol 1928g, diisopropylamine 25g (0.25mol) were added to a four-necked flask, heated to 60°C, 28% sodium methanol solution 396.4g (0.5mol) was added slowly dropwise, and the etherification reaction was carried out at a maintained temperature for 5h. Samples were taken to monitor the reaction process. After the reaction was completed, the solvent was removed by distillation under reduced pressure, 200g of water was added, the slurry was formed by stirring, the solids were washed, the solids were collected by filtration, the filter cake was washed with water, and dried in vacuum to obtain 141.46g of 2-chloro-6-nitroanisole, with an etherification reaction yield of 85% and a purity of 95%. 39.9g 2-chloro-6-nitroanisole was added into 500mL autoclave, 0.4g 1% platinum-carbon catalyst and 120g methanol were added, the temperature was raised to 40℃, the pressure was adjusted to 0.4MPa, the reaction was carried out for 18h, and samples were taken to monitor the process. At the end of the reaction, the catalyst was removed by filtration, methanol was removed by distillation under reduced pressure, and 32g of 3-chloroanisidine was precipitated, with 96% yield, >93% purity, and 81.6% total yield.
