Potassium Iodide → 5-Bromo-2-cyclopropyliodobenzene

Beteiligte Stoffe

Reaktionsschritte

5-Bromo-2-cyclopropylaniline (4.74 g) is added to a solution of para-toluene sulfonic acid monohydrate (12.2 g, 0.064 mol) in acetonitrile (130 ml), followed by stirring for 10 minutes at room temperature. The suspension is then cooled to 10° C. and a mixed solution of sodium nitrite (8.9 g, 0.054 mol) and potassium iodide (3.1 g, 0.044 mol) in water (16 ml) is added dropwise over 30 minutes. Once the addition is complete the reaction mixture is allowed to stir at 10° C. for 20 minutes and then at room temperature for 4 hours. The reaction mixture is basified to pH 9-10 with aqueous sodium bicarbonate, followed by addition of ethyl acetate and 10% aqueous sodium metabisulphite. The phases are separated and the aqueous layer is extracted again with ethyl acetate (×2). Organics are combined, washed with brine, dried over magnesium sulfate then concentrated in vacuo to give the crude product which is purified by flash column chromatography on silica gel (isohexane eluant) to afford 5-bromo-2-cyclopropyliodobenzene as a colourless oil.

Herkunft & Nachweise