Diethyl 4-methoxy-2-nitrophenylmalonate (1.1 g, 36 mmol) was used as a raw material, which was dissolved in 5 mL of 6N hydrochloric acid solution and the reaction was carried out at reflux under stirring conditions for 13 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and the precipitated brown precipitate was collected by filtration and washed with deionized water. The resulting precipitate was dissolved in 1.5 mL of 2N sodium hydroxide solution and subsequently extracted with 1 mL of ethyl acetate. The aqueous layer was mixed with 0.1 g Darco-G60 and refluxed for thermal filtration. The filtrate was acidified with 0.5 mL of 6N sulfuric acid and cooled in a refrigerator. The precipitated tan precipitate was collected by vacuum filtration, washed with deionized water and dried under vacuum to give 0.6 g of 4-methoxy-2-nitrophenylacetic acid in 82% yield.
