Chloroacetyl chloride → 2-chloro-N-(5-chloropyridin-2-yl)acetamide

Chloroacetyl chloride (95.5 ml) is dissolved in dichloromethane (500 ml), and thereto is added dropwise a suspension of 2-amino-5-chloropyridine (128.6 g) and triethylamine (169 ml) in dichloromethane (1000 ml) under ice-cooling. The reaction solution is warmed to room temperature and stirred for 0.5 hours. The reaction solution is concentrated under reduced pressure, and thereto is poured ice-water, followed by extraction with ethyl acetate. The organic layer is washed with saturated brine, dried over sodium sulfate and treated with activated charcoal. After filtration to remove insoluble materials, the filtrate is concentrated under reduced pressure and the resulting residue is suspended in diisopropyl ether. The precipitates are collected by filtration, washed with diisopropyl ether and dried to give the title compound (153.4 g).