General procedure for the synthesis of 3-amino-4-nitrobenzoic acid from 3-amino-4-nitrobenzonitrile: A mixture of 3-amino-4-nitrobenzonitrile (1.2 g, 7.36 mmol), concentrated hydrochloric acid (50 mL), and deionized water (100 mL) was heated to reflux and the reaction was sustained for 48 hours. Upon completion of the reaction, the mixture was cooled to room temperature and the resulting orange solid product was collected by diafiltration. The solid was washed repeatedly with deionized water until the wash solution was neutral, resulting in 1.11 g of 3-amino-4-nitrobenzoic acid in 83% yield.
