Synthesis
Preparation of m-fluorophenylacetic acid: 350 g of 32% HCl and 250 g of 3-fluoroaniline were added to the reaction flask, heated and stirred until dissolved clear. Cool down to -5 to 5 , 20 g tetramethyl ammonium chloride and 20 g copper chloride. Acetone solution containing 300 g of vinylidene chloride was added dropwise. Maintaining the temperature, slowly add dropwise a solution containing 230 g of isopropyl nitrite and 200 g of acetone. Hold the reaction for 2 hours. The reaction was completed and quenched. Dichloromethane was added and extracted and distilled and collected to give 1-(2,2,2-trichloroethyl)-3-fluorobenzene 398 g. A three-necked flask was protected with nitrogen and 500 g of water and 60 g of p-toluenesulfonic acid were added. Heated to 80-95C. 300g of intermediate 1-(2,2,2-trichloroethyl)-3-fluorobenzene was added dropwise. Dropwise addition was completed and the reaction was held for 8 hours. The reaction was completed. The system was quenched by adding dropwise to ice water at reduced temperature. Filtered, washed with water, dried and recrystallized with dichloroethane to obtain the pure m-fluorophenylacetic acid 151.2 g, HPLC purity greater than 99 wt%.
