General procedure for the synthesis of 3-iodoquinoline from 3-bromoquinoline: In an oven-dried sealable glass tube, a magnetic stirring bar, 3-bromoquinoline (1.04 g, 5.0 mmol), freshly milled sodium iodide (1.52 g, 10.0 mmol), and copper(I) iodide (100 mg, 0.5 mmol) were added in sequence. After installing the rubber septum, the reaction vessel was evacuated and backfilled with argon gas, and this process was repeated three times. Subsequently, 1,4-dioxane (5 mL) and N,N'-dimethylethylenediamine (0.12 mL, 1.0 mmol) were added to the vessel via syringe. The rubber septum was removed, the reaction vessel was immediately sealed with a PTFE screw cap, and the reaction was heated at 110 °C for 22 hours. Upon completion of the reaction, it was cooled to room temperature and the reaction mixture was diluted with saturated aqueous ammonium chloride solution (30 mL) and extracted with dichloromethane (4 x 25 mL). The organic layers were combined, washed with brine (30 mL), dried over anhydrous sodium sulfate and concentrated to give a brown residue. The residue was recrystallized by hexane/ethyl acetate mixed solvent to give 3-iodoquinoline (1.15 g, 90% yield).The NMR hydrogen spectrum of 3-iodoquinoline (600 MHz, CDCl3) δ 9.04 (d, J = 1.8 Hz, 1H), 8.55-8.54 (m, 1H), 8.08-8.06 (m, 1H), 7.75-7.71 (m , 2H), 7.58-7.56 (m, 1H); NMR carbon spectrum (150 MHz, CDCl3) δ 155.57, 146.34, 143.71, 130.03, 130.01, 129.50, 127.41, 126.79, 89.77; high-resolution mass spectrometry (ESI-TOF) calculated values C9H7IN [M+ H]+: 255.9618, measured value: 255.9623.
