Sulfuric Acid → 3,5-Dibromoquinoline

To concentrated H2SO4 (130 ml) was added dropwise at 0° C., over 80 min, 3-bromoquinoline (50 g) at a rate allowing the internal temperature to be maintained between 0° and 10° C. After the addition was complete, NBS (48 g) was added portionwise and the reaction mixture was stirred at rt overnight. The reaction mixture was poured onto ice (2 l) and the resulting solid was dissolved in DCM (600 ml). The aq. layer was further extracted with DCM (600 ml) and the combined extracts were washed with 1M NaOH (300 ml) and concentrated in vacuo. The residue was adsorbed on SiO2 and the resulting dispersal was loaded on the top of a column and eluted with a DCM-Hex (1-1, 3 l) then DCM (3 l) and finally DCM-ether (1-1, 2 l). The title compound was recovered from the last fraction after evaporation to yield 40 g of a white solid.

1. temperatureto be maintained between 0° and 10° C
2. additionAfter the addition
3. additionThe reaction mixture was poured onto ice (2 l)
4. extractionThe aq. layer was further extracted with DCM (600 ml)
5. washthe combined extracts were washed with 1M NaOH (300 ml)
6. concentrationconcentrated in vacuo
7. washeluted with a DCM-Hex (1-1, 3 l)
8. customThe title compound was recovered from the last fraction
9. customafter evaporation

ORD record

ord-311b572ba0bb445abcad7f3fc5082e6d

Source dataset

uspto-grants-2010_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07820655B2