2,6-Dichloro-N-[4-(2-oxo-1,2-dihydro-pyridin-4-yl)-benzyl]-benzamide (1.62 g, 4.34 mmol) was suspended in 15 mL dichloromethone. Chloromethylchloroformate (0.672 g, 5.21 mmol) was added followed by 3 mL DMF. The mixture was stirred at room temperature for five hours. After diluting with 200 mL ethyl acetate, the organic phase was washed with saturated, aqueous sodium bicarbonate solution and brine, dried with magnesium sulfate and evaporated under vacuum. The crude 2,6-dichloro-N-[4-(1-chloromethyl-2-oxo-1,2-dihydro-pyridin-4-yl)-benzyl]-benzamide was used in the following step without further purification.
