509142-48-7

288315-03-7

122-01-0

509142-48-7

GENERAL STEPS: Example 63 (a) Synthesis of 4-bromo-2-(trifluoromethoxy)benzoic acid Thionyl chloride (5 mL) was added to 4-chlorobenzoic acid (0.49 g, 3.1 mmol). After addition of 2 drops of anhydrous DMF, the reaction mixture was refluxed under nitrogen protection for about 15 min. Upon completion of the reaction, the solvent was removed by vacuum evaporation and the residue was dissolved in dichloromethane (5 mL). Subsequently, 3,3-difluoroazetidine hydrochloride (0.42 g, 3.3 mmol) and triethylamine (0.91 mL, 6.6 mmol) were added. The reaction mixture was stirred at room temperature for about 15 minutes. The reaction solution was diluted with dichloromethane and washed sequentially with saturated aqueous sodium bicarbonate solution and water. The organic phase was treated with anhydrous ethanol (until a clarified solution was obtained) and the solvent was evaporated in vacuum to give 4-bromo-2-trifluoromethoxybenzoic acid as a solid in 94% yield. The resulting product could be used in the next reaction without further purification. 1H NMR (400 MHz, DMSO-d6) δ ppm 7.75-7.66 (m, 2H), 7.58-7.48 (m, 2H), 5.06-4.15 (m, 4H); MS (ESI) m/z 232 (M + 1).