4-Amino-5-chloro-2-methoxybenzoic acid

20896-27-9

7206-70-4

The general procedure for the synthesis of 4-amino-5-chloro-2-methoxybenzoic acid using methyl 4-amino-5-chloro-2-methoxybenzoate as the raw material was as follows: (3) The above obtained methyl 4-amino-5-chloro-2-methoxybenzoate was mixed with potassium hydroxide at a molar ratio of 1:2.2, and stirred at reflux in a solvent mixture of 7 liters of methanol and water (in a ratio of 5:2, v/v) for more than 2 hours. Activated carbon was then added for decolorization and refluxing was continued for 30 minutes. After completion of the reaction, the activated carbon was removed by filtration. The filtrate was concentrated on a rotary evaporator to remove most of the solvent and then diluted by adding water. The pH was slowly adjusted to 5 with a 3 mol/L hydrochloric acid solution, at which point a white solid precipitated from the aqueous solution. The solid product was collected by filtration and dried to give 1.93 kg of 4-amino-5-chloro-2-methoxybenzoic acid in 91.4% yield. The structure of the product can be confirmed by hydrogen spectroscopy (Figure 1).