To solution of (2,4,5-trichloro-phenoxy)-acetic acid (150 mg, 0.59 mmol), 2-amino isonicotinic acid methyl ester (179 mg, 1.18 mmol) and DMAP (144 mg, 1.18 mmol) in DMF 13 mL was added PyBOP (614 mg, 1.18 mmol) at room temperature. Reaction mixture was stared at room temperature. Resulting mixture poured onto ice cold water, was diluted by ethyl acetate. The organic phase was separated, sequentially washed with aqueous sodium bicarbonate, brine and water, dried over anhydrous MgSO4, and concentrated. The residue was purified by flash silica gel column chromatography (EtoAC:Hexane=1:1) to give 2-[2-(2,4,5-trichloro-phenoxy)-acetylamino]-isonicotinic acid methyl ester as a colorless solid (0.056 g, 24.45% yield).
