2-bromo-4'-methylpropiophenone was prepared as follows: (1) Under argon protection, (4g, 30mmol) anhydrous aluminum chloride was added to the reaction flask, and then 20ml of anhydrous methylene chloride was added, and stirring was done to dissolve it. After dissolution, (1.7 g, 10 mmol) of 2-bromopropionyl chloride was added and stirring was continued for 20 min, then (0.92 g, 10 mmol) of toluene was added, and the dropwise addition was completed within 30 min. After the dropwise addition was completed, the solution was refluxed for 2H and cooled to room temperature after refluxing. After cooling, the solution was poured into 40 ml of ice water and 20 ml of dichloromethane and 20 ml of 6N hydrochloric acid were added, and the solution was shaken vigorously and allowed to partition. After layering, the lower dichloromethane phase was left, and the dichloromethane phase was washed twice with 1NHCL, then dried with anhydrous magnesium sulfate, filtered, and evaporated to obtain a transparent oily substance. Transparent material in a crystallization dish and add ether to dissolve, and then slowly add drops of petroleum ether to slightly turbid, covered and clamped a piece of paper rest in the fume hood in the crystallization, to obtain 1.37g product 2-bromo-4'-methylpropiophenone transparent crystals.
