Hydrogen Bromide → 5-Bromoquinoline

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).

1. filtrationfiltered
2. extractionThe filtrate was extracted three times with 50 mL ethyl ether
3. concentrationthe combined ether layers were concentrated in vacuo
4. filtrationThe resulting residue was combined with precipitate from the above filtration
5. dissolutiondissolved in 50% MeOH
6. filtrationCH2Cl2 and filtered
7. concentrationThe filtrate was concentrated in vacuo
8. dissolutiondissolved in 10% (10% NH4OH:MeOH)
9. filtrationCH2Cl2 and filtered over silica
10. concentrationThe filtrate was concentrated in vacuo

ORD record

ord-4b76c96d44fa4cf5a1ca8f6ddafae3d4

Source dataset

uspto-grants-2003_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06534510B2