Piperazine → 6-Fluoro-2-piperazin-1-yl-quinoline

To a solution of 2-chloro-6-fluoroquinoline (6.8 g, 37.4 mmol) in N,N-dimethylformamide (200 ml) in a round-bottomed flask was added potassium carbonate (10.4 g, 75.2 mmol) and piperazine (19.2 g, 222.9 mmol) at room temperature. After heating the contents to 130° C. for 5 hours, the reaction mixture was concentrated under vacuum to a minimum volume and then quenched with water (300 ml) and extracted with dichloromethane (3×200 ml). The combined organic layers were washed with brine (100 ml), dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The crude material was purified by silica gel chromatography using 1-2.5% methanol in dichloromethane to elute. The product containing fractions were combined and concentrated to afford 6-fluoro-2-(piperazin-1-yl)quinoline as a brown solid (4.5 g, 52%); (ES, m/z): [M+H]+ 232; 1H NMR (300 MHz, CDCl3): δ 7.86 (d, J=9.3 Hz, 1H), 7.62-7.72 (m, 1H), 7.32-7.36 (m, 1H), 7.24-7.29 (m, 1H), 7.01 (d, J=9.3 Hz, 1H), 3.73 (t, J=5.1 Hz, 4H), 3.05 (t, J=5.1 Hz, 4H).