To 4-methyl-pyridine (806 μL, 8.33 mmol) in anhydrous tetrahydrofuran (35 mL) was added at 0° C. sodium hexamethyldisilazide 1 M in tetrahydrofuran (16.66 mL, 16.66 mmol) and the reaction was stirred for 20 minutes. 3-Dibenzylamino-2,6-difluoro-benzoic acid benzyl ester (3.691 g, 8.33 mmol) was dissolved in tetrahydrofuran (5 mL) and added dropwise to the solution with 4-methyl-pyridine, the reaction was stirred at 0° C. for one hour. The reaction was poured into saturated ammonium chloride solution and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous sodium sulfate, filtrate and concentrated under reduced pressure. The crude was purified by silica gel column chromatography eluting with ethyl acetate 30% in hexane to give the title compound (1.775 g, 50%).
