| preparation | dissolve 30.0g m-dinitrobenzene (0.18mmol) in 180mL of concentrated sulfuric acid, heat to 80 ℃ to keep the temperature between 80-90 ℃, add 44.5gNBS(0.25mol) into the above solution in nine batches, continue to react for 30min after adding, pour into 600mL of ice water after cooling, and precipitate white precipitate, succession filtration, water washing and drying to obtain 41.3g of white solid 3,5-dinitrobromobenzene with a yield of 93.7%; Weigh 1g of sodium (43.4mmol) and dissolve it in methanol to prepare sodium methoxide solution, add 8.7 g3, 5-dinitrobromobenzene (35.2mmol) to the above sodium methoxide solution, refluxing at 45 ℃ for 2 hours, cooling to room temperature, treating with 50mL1N hydrochloric acid solution, and extracting with dichloromethane, after the organic items are combined, the saturated salt is washed 3 times, the anhydrous magnesium sulfate is dried, the solvent is filtered and evaporated, and the crude product is separated by column (petroleum ether: dichloromethane = 5:1) to obtain white powdered solid 3-bromo-5-nitroanisole 4.6g, yield: 56.3%. |
