Dolbier HW Solutions 515

Dolbier HW Solutions 515 - m-nitroaniline by any of a...

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( d ) The conversion of p -chloronitrobenzene to p -chloroaniline was cited as an example in the text to illustrate reduction of aromatic nitro compounds to arylamines. p -Chloronitrobenzene is prepared by nitration of chlorobenzene. The para isomer accounts for 69% of the product in this reaction (30% is ortho, 1% meta). Separation of p -chloronitrobenzene and its reduction completes the synthesis. Chlorination of nitrobenzene would not be a suitable route to the required intermediate, because it would produce mainly m -chloronitrobenzene. ( e ) The synthesis of m -aminoacetophenone may be carried out by the scheme shown: The acetyl group is attached to the ring by Friedel Crafts acylation. It is a meta director, and its nitration gives the proper orientation of substituents. The order of the f rst two steps cannot be reversed, because Friedel Crafts acylation of nitrobenzene is not possible (Section 12.16). Once prepared, m -nitroacetophenone can be reduced to
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Unformatted text preview: m-nitroaniline by any of a number of reagents. Indeed, all three reducing combinations described in the text have been employed for this transformation. Yield Reducing agent (%) m-Nitroacetophenone H 2 , Pt 94 Fe, HCl 84 m-Aminoacetophenone Sn, HCl 82 22.12 ( b ) Dibenzylamine is a secondary amine and can be prepared by reductive amination of benz-aldehyde with benzylamine. H 2 , Ni C 6 H 5 CH O C 6 H 5 CH 2 NH 2 C 6 H 5 CH 2 NHCH 2 C 6 H 5 1 Dibenzylamine Benzylamine Benzaldehyde Benzene HNO 3 H 2 SO 4 reduce AlCl 3 CH 3 CCl O Acetophenone CCH 3 O m-Nitroacetophenone NO 2 CCH 3 O m-Aminoacetophenone NH 2 CCH 3 O p-Chloroaniline Cl NH 2 p-Chloronitrobenzene Cl NO 2 1. Fe, HCl; 2. HO 2 or 1. Sn, HCl; 2. HO 2 H 2 , catalyst; or Benzene Chlorobenzene Cl o-Chloronitrobenzene NO 2 Cl p-Chloronitrobenzene Cl NO 2 Cl 2 FeCl 3 HNO 3 H 2 SO 4 1 AMINES 609...
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This note was uploaded on 10/03/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.

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