5-Bromoquinoline

611-34-7

4964-71-0

General procedure for the synthesis of 5-bromoquinoline from 5-aminoquinoline: 1. dissolve quinolin-5-amine (3.37 g, 23.38 mmol) in 9 mL of water and 11 mL of hydrogen bromide (48% aqueous solution), and the resulting solution is cooled to 0°C. 2. a solution of sodium nitrite (1.94 g, 28.12 mmol) dissolved in 9 mL of water was added slowly and dropwise. 3. the reaction mixture was stirred at room temperature for 5 minutes. 4. The above solution was added slowly dropwise to a pre-prepared solution of copper (I) bromide (4.02 g, 28.02 mmol dissolved in 23 mL of 48% aqueous hydrogen bromide). 5. The reaction mixture was stirred at 75°C for 2 hours. 6. Upon completion of the reaction, the reaction mixture was alkalized with sodium hydroxide solution. 7. The reaction mixture was extracted twice with ethyl acetate and the organic phases were combined. 8. The organic phase was washed sequentially with water and brine, and then dried over anhydrous sodium sulfate. 9. The desiccant was removed by filtration and the solvent was evaporated under reduced pressure to give 2.98 g (61% yield) of the target product 5-bromoquinoline. Product characterization data: 1H NMR (CDCl3) δ ppm: 7.44-7.63 (m, 2H), 7.84 (d, J = 7.42 Hz, 1H), 8.10 (d, J = 8.24 Hz, 1H), 8.56 (d, J = 8.51 Hz, 1H), 8.94 (br.s., 1H). HPLC/MS (9 min) retention time 5.68 min. Mass spectral data: m/z 208 (M), 210 (M+2).