General procedure for the synthesis of 2-chloro-5-iodo-3-(trifluoromethyl)pyridine from 2-hydroxy-5-iodo-3-(trifluoromethyl)pyridine: In a microwave reaction vial, 5-iodo-3-trifluoromethyl-2-pyridinol (1 g, 3.47 mmol) was added to a pre-cooled mixture of POCl3 (1.60 mL) and DMF (1 mL). After sealing the vial, the reaction was heated at 110 °C for 20 min. Upon completion of the reaction, the mixture was cooled to room temperature and slowly poured into ice water. At this point, the product precipitated as a precipitate. The precipitate was collected by filtration, washed with cold water and dried to give 661 mg of the product in the form of a light brown powder in 62% yield. The structure of the product was determined by 1H NMR (500 MHz, CDCl3) δ 8.32 (d, J = 2.0 Hz, 1H), 8.81 (d, J = 2.0 Hz, 1H) and 13C NMR (250 MHz, CDCl3) δ 89.4, 121.2 (q, JC-F = 273.3 Hz), 126.8 (q, JC-F = 33.6 Hz), 144.34, 148.5, 158.7 for confirmation.
