The general procedure for the synthesis of o-nitro-p-methylsulfonyl chlorobenzene from p-methylsulfonyl chlorobenzene is as follows: In a 100 mL three-necked round-bottomed flask equipped with a stirrer, a dropping funnel, and a thermometer, 24 mL of concentrated sulfuric acid and 11.3 g of p-chlorophenyl sulfone were added, and the mixture was stirred until p-chlorophenyl sulfone was completely dissolved. At a temperature below 25°C, 6 mL of nitric acid was added slowly and dropwise. After the dropwise addition was completed, the reaction temperature was maintained at 25°C and stirring was continued for 2 hours. After the reaction was completed, the reaction solution was slowly poured into a beaker and appropriate amount of ice water was added while stirring until a white precipitate was precipitated. After the mixture was cooled to room temperature, filtration was carried out to separate the solid product. The resulting white powdery solid was dried under vacuum and weighed 13.9 g, with a melting point of 124.2~125.1 °C, a purity of 99.9% and a yield of 99.7%.
