General procedure for the synthesis of 2,5,6-trichloropyridin-3-amide from 2,5,6-trichloronicotinoyl chloride: a solution of dioxane (20 ml) of 2,5,6-trichloronicotinoyl chloride (2.5 g, 10.2 mmol) was slowly added dropwise to 10 ml of ammonium hydroxide (28% NH3 aqueous solution) at 0 °C. After the dropwise addition, the reaction mixture was continued to be stirred at 0°C for 10 min. Subsequently, extraction was carried out with dichloromethane (3 x 50 ml). All organic phases were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford 2,5,6-trichloropyridin-3-amide (2.3 g, 100% yield), which could be used in subsequent reactions without further purification.
