Hydrogen Peroxide → N-(2-methylsulfinyl-1,1-dimethyl-ethyl)-N'-(2-methyl-4-(1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl)phenyl)phthalamide

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Reaction Conditions

Reaction Steps

Sodium hydroxide (17.78 g) and sodium hydrogencarbonate (35.57 g) were dissolved in water (253 mL), followed by adding thereto 2-methyl-1-methylthio-2-propanamine (53 g) and 1,2-dichloroethane (253 mL), and to the resulting mixture was added dropwise phthaloyl dichloride (85.95 g) at 40° C. or lower. After completion of the dropwise addition, the resulting mixture was stirred at 40° C. for 30 minutes and the organic layer was separated to prepare a solution of N-[1,1-dimethyl-2-(methylthio)ethyl]isophthalimide in 1,2-dichloroethane. The previously prepared isophthalimide solution and 35% hydrogen peroxide (45.27 g) were slowly dropped at the same time into a mixture of 2-methyl-4-[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-aniline (110.7 g), p-toluenesulfonic acid monohydrate (2.01 g) and 1,2-dichloroethane (40 mL) at 60° C. and then stirred at 60° C. for 3 hours. An aqueous sodium sulfite solution was added dropwise to the thus obtained reaction mixture at the same temperature to decompose the excess oxidizing agent. Then, the resulting mixture was neutralized with an aqueous sodium hydrogencarbonate solution, after which the organic layer was separated. The organic layer obtained was slowly cooled to 20° C. The crystals precipitated were filtered, washed with water and then dried to obtain 184.11 g (yield 80%) of the title compound.

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