2-Chloro-5-(trifluoroMethoxy)pyridine

1221171-73-8

1206972-45-3

General procedure for the synthesis of 2-chloro-5-(trifluoromethoxy)pyridine (6) from 2-chloro-5-trichloromethoxypyridine (5,7.4 g, 30.0 mmol): 2-chloro-5-trichloromethoxypyridine (5) was added slowly and dropwise to a molten mixture of SbF3 (10.7 g, 60.0 mmol, 2.0 equiv) and SbCl5 (1.4 g, 0.6 mL, 4.6 mmol, 0.15 equiv) in a molten mixture. The reaction mixture was stirred at 120 °C to 150 °C for 3 h. The progress of the reaction was monitored by gas chromatography (GC) to confirm the complete conversion of the feedstock and the disappearance of the by-product OCF2Cl. Upon completion of the reaction, the mixture was cooled to 0 °C and dissolved in dichloromethane (100 mL). Subsequently, the reaction was quenched with saturated aqueous sodium bicarbonate solution (100 mL) and potassium fluoride solution (20%, 50 mL), and the aqueous layer was extracted with dichloromethane (2 x 50 mL). The organic layers were combined, dried with anhydrous sodium sulfate, and the solvent was removed by distillation under reduced pressure. The crude product was purified by vacuum distillation to give 2-chloro-5-(trifluoromethoxy)pyridine (6,3.6 g, 18.0 mmol, 60% yield) as a colorless oil. The boiling point of the product was 41-43 °C/20 mbar.1H NMR (CDCl3, 300 MHz): δ=8.35 (s,1H), 7.55 (d,J=8.7Hz,1H), 7.41 (d,J=8.7Hz,1H).13C NMR (CDCl3, 75 MHz): δ=149.3,142.7,140.1, 131.3,125.1,120.2 (q,J=259Hz).MS (EI): m/z=197[M+],162[M+-Cl].