GENERAL STEPS: In a 500 mL round bottom flask, 84.5 g (414 mmol) of 2,6-dihydroxy-3-cyano-4-(trifluoromethyl)pyridine, 400 g of phosphoryl chloride and 35 g of catalyst were added. The mixture was heated and refluxed for 20 h, during which the progress of the reaction was monitored by TLC. Upon completion of the reaction, the reflux unit was changed to a distillation unit to evaporate the excess phosphorus trichloride. The reaction mixture was slowly poured into an ice-water mixture and a white solid was precipitated. The solid was collected by filtration and dried to give 79.6 g of the target product 2,6-dichloro-3-cyano-4-(trifluoromethyl)pyridine in 79.78% yield.
