13290-96-5

67-56-1

618-88-2

13290-96-5

In a 100 mL three-necked round-bottomed flask equipped with a condenser tube, an electric stirrer and a thermometer, 5.0 g of 5-nitroisophthalic acid and 33.3 mL of methanol were added sequentially. The mixture was stirred under nitrogen protection at room temperature for about 3 minutes until the solid was completely dissolved to give a colorless transparent solution. Subsequently, 1.0 mL of concentrated sulfuric acid was slowly added dropwise and heated to reflux, and after the reaction for about 3 hours, white solid precipitation was observed. The progress of the reaction was monitored by thin layer chromatography (TLC, unfolding agent ratio of dichloromethane:methanol=10:1). Upon completion of the reaction, it was cooled to room temperature, crystals were precipitated and the solid product was collected by filtration. The filter cake was washed with deionized water and finally mixed with a small amount of water and dried to obtain dimethyl 5-nitroisophthalate. The product yield was 98%.