5-Methoxy-1-[4-(trifluoromethyl)phenyl]-1-pentanone

17913-18-7

2967-66-0

61718-80-7

Under nitrogen atmosphere, 1500 mL of anhydrous tetrahydrofuran and 108 g of magnesium shavings were added to the reaction flask, followed by a few drops of iodomethane as initiator. The reaction system was warmed to 75 °C and stirred until the magnesium shavings were completely dissolved. Slowly 602.1 g of 1-chloro-4-methoxybutane was added dropwise, and after completion of the dropwise addition, the reaction was kept at a constant temperature for 13 hours. After the reaction was complete, cooled to room temperature, then 45.88 g of methyl 4-(trifluoromethyl)benzoate prepared in step 1 was slowly added dropwise at a controlled rate of 5 g per min. After completion of the dropwise addition, the reaction mixture was heated to 70 °C and maintained at a constant temperature for 4-6 hours. After the reaction was complete, it was cooled to room temperature and acidified by slowly adding ice hydrochloric acid to the reaction solution. The reaction mixture was extracted with tetrahydrofuran and the organic phases were combined and concentrated. The aqueous phase was further extracted with dichloromethane and the organic phase was combined with the previously concentrated tetrahydrofuran phase. The combined organic phases were dried with anhydrous sodium sulfate, filtered and concentrated to give 152.36 g of 1-[4-(trifluoromethyl)phenyl]-5-methoxyvalerophenone in 90.5% yield.