Hydrogen Bromide → 5-Bromoquinoline

Participants

Reaction Conditions

Reaction Steps

5-Aminoquinoline (5 g, 34.7 mmol) is dissolved in HBr 48% (15 mL) and water (15 mL) and then cooled to 0° C. A solution of NaNO2 (2.5 g, 36.2 mmol) in water (15 mL) is added over about 10 minutes. The mixture is stirred for about 30 minutes at 0° C. and then at r.t. for about 1.5 hours. The mixture is transferred to an addition funnel and 75° C. solution of CuBr is added over 30 minutes. The mixture is stirred for about 30 minutes and then allowed to cool to r.t., which is then stirred for another 2 hours. The mixture is cooled to 0° C. and adjusted to pH of about 14 with 5N NaOH. The solution is filtered, and the solids are washed with DCM. The aqueous layer is extracted with DCM (2×200 mL), and the organic fractions are combined and concentrated. The residue is chromatographed on silica gel to give about 1.6 g of 5-bromoquinoline (22%).

Provenance & Evidence