Phosphorus tribromide → 4-(2-Bromoethyl)benzonitrile

Beteiligte Stoffe

Reaktionsschritte

A solution of phosphorus tribromide (5 g) in carbon tetrachloride (10 ml) was added, dropwise, to a solution of 4-cyanophenethyl alcohol (8.06 g) in carbon tetrachloride (60 ml). The mixture was heated under reflux for 4 hours. On cooling to room temperature, the mixture was poured onto ice (200 g). The layers were separated and the organic layer was washed with 10% aqueous sodium carbonate (50 ml) and brine (50 ml), dried (MgSO4) and concentrated in vacuo to give a colourless oil which solidified on standing. The solid was chromatographed on silica eluting with ethyl acetate containing hexane (20%). The fractions containing the less polar (higher Rf) product were combined and concentrated in vacuo to give 4-cyanophenethyl bromide as a yellow oil which solidified on standing, yield 8.9 g. The fractions containing the more polar (lower Rf) product were combined and concentrated in vacuo to give the title compound as a colourless solid, yield 0.47 g, m.p. 152°-153° .

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