6-Fluoro-1,2-dihydroquinolin-2-one (7.8 g, 47.8 mmol) was used as a raw material, which was suspended in phosphoryl chloride (72.2 g, 470.9 mmol) and the reaction was stirred at 100 °C in an oil bath for 4 hours. Upon completion of the reaction, excess phosphorus trichloride was removed by vacuum concentration, followed by addition of ice water (200 ml) to the reaction mixture to quench the reaction. The resulting precipitate was washed with water (2 x 80 ml) and dried to afford 2-chloro-6-fluoroquinoline as an off-white solid (6.8 g, 78% yield). The product was confirmed by mass spectrometry (ES, m/z): [M + H]+ 182; 1H NMR (300 MHz, DMSO) data were as follows: δ 8.43 (d, J=8.4 Hz, 1H), 8.01 (dd, J=5.4 Hz, 9.3 Hz, 1H), 7.87 (dd, J=3.0 Hz, 9.3 Hz, 1H), 7.72-7.78 (m, 1H), 7.45 (d, J=8.4Hz, 1H).
