Iron-mediated reduction of aromatic nitro- groups to amines.; anilines
Submitted Mar 22, 2007, published Mar 23, 2007
Iron powder (Aldrich, as received)
Iron(III) chloride hexahydrate (Aldrich, as received)
Ethanol (Fisher, absolute, as received)
Acetic acid (Fisher, as received)
5-Fluoro-2-iodonitrobenzene (prepared from 4-fluoro-2-nitroaniline via a Sandmeyer reaction)
5-Fluoro-2-iodonitrobenzene (17.4 g; 65.2 mmol) was dissolved in a mixture of ethanol (100 mL) and acetic acid (12 mL) in a large RB flask (at least 500 mL) equipped with an efficient condenser, and the stirred mixture brought to a gentle reflux. Iron powder (26.6 g) was added, followed immediately by iron(III) chloride hexahydrate (3 g). The mixture was refluxed for a further 3 hours, then cooled and filtered using a Buchner funnel (with the help, when necessary, of the addition of ether or ethanol.)
To the filtrate was added ether (300 mL) and water (300 mL), and the aqueous layer was repeatedly extracted with ether. The combined organic layers were dried and concentrated, giving 5-fluoro-2-iodoaniline and a pure white solid (14.27 g; 92%).
1H nmr. CDCl3. 4.21 (2H, bs, NH2), 6.28 (1H, td, J = 8.5, 2.8), 6.49 (1H, dd, J = 10.5, 2.8), 7.57 (1H, dd, 8.7, 6.2)
B. Gabriele, G. Salerno, L. Veltri, M. Costa, C. Massera, Eur. J. Org. Chem. 2001, 4607.
Keywords: Iron, reduction, amines, aromatics/arenes