5-Aminoquinoline → 5-Fluoroquinoline

Participants

Reaction Steps

To a suspension of 5-aminoquinoline (10.0 g, 0.069 mol) in 48% HBF4 (40 mL) at 0° C. was added portionwise sodium nitrite. This was stirred for 1 hour and then poured into 1:1 ethyl acetate/diethyl ether (50 mL). The resulting suspension was filtered and the solid dried. This solid was added portionwise to refluxing xylene (80 mL) and stirred for 2 hours then allowed to cool. The xylene was decanted off and the residue was dissolved in 1N aqueous hydrochloric acid (100 mL). After neutralization with sodium carbonate, the mixture was extracted with ethyl acetate (3×80 mL). The extracts were dried over sodium sulfate, filtered and the volatiles were removed in vacuo. The residue was purified by silica gel column chromatography, eluting with 2% ethyl acetate in petroleum ether to afford 5-fluoroquinoline as a colorless oil (2.5 g, 24.5%).

Provenance & Evidence