4-Chloro-6-fluoroquinoline

38470-26-7

391-77-5

General procedure for the synthesis of 4-chloro-6-fluoroquinoline from 6-fluoro-2,3-dihydroquinolin-4(1H)-one: 412.55 mL of phosphoryl chloride, 11.5 g of iodine, and 165.0 g of manganese dioxide were added to a four-necked flask fitted with a stirrer and heated under stirring to 50 °C. Subsequently, 660 mL of a dichloroethane solution containing 165.02 g of 6-fluoro-2,3-dihydroquinolin-4(1H)-one was slowly added dropwise. After completion of the dropwise addition, the reaction mixture was refluxed for 2 hours. After completion of the reaction, the dichloroethane solvent was removed by distillation under reduced pressure. The residue was neutralized to pH 5-6 with cold aqueous sodium bicarbonate and filtered. The filter cake was washed with water to neutral and finally dried under vacuum to give 154.22 g of light gray solid 4-chloro-6-fluoroquinoline in 85.0% yield.