Hydrogen Bromide → 5-Bromoquinoline

Participants

Reaction Steps

To a 0° C. mixture of 1.0022 g (6.94 mmol) 5-aminoquinoline (9) and 6 mL 24% aqueous hydrobromic acid was added a solution of 0.5 g (7 mmol) sodium nitrite in 3 mL H2O. After 5 min at 0° C., the mixture was added over 5 min to 1.2026 g (8.38 mmol) cuprous bromide in 10 mL 47% aqueous hydrobromic acid. After stirring at room temperature for 7.5 h, the reaction mixture was basified with ice and 50% aqueous NaOH and filtered. The filtrate was extracted three times with 50 mL ethyl ether, and the combined ether layers were concentrated in vacuo. The resulting residue was combined with precipitate from the above filtration, dissolved in 50% MeOH:CH2Cl2 and filtered. The filtrate was concentrated in vacuo, dissolved in 10% (10% NH4OH:MeOH):CH2Cl2 and filtered over silica. The filtrate was concentrated in vacuo to yield 10. 1H NMR (DMSO, 400 MHz) δ 8.997 (d, 1H, J=2.83 Hz, ArH); 8.525 (d, 1H, J=8.59 Hz, ArH); 8.089 (d, 1H, J=8.50 Hz, ArH); 8.000 (d, 1H, J=7.49 Hz, ArH); 7.741-7.701 Hz (m, 2H, ArH); MS (Electrospray): m/z 207.9, 209.9 (M+H, 79Br, 81Br).

Provenance & Evidence