How Do Amines Act as Nucleophiles

The most commonly used metal-reducing agents are iron, zinc, and tin in dilute HCl. When reduced hy this method, the amine is obtained as a salt, which is then treated with a strong hase to liberate the free amine. 

Show the reagents that will bring about each step in this conversion of toluene to 4-aminobenzoic acid  

STEP 1 Nitration of toluene, using nitric acid/sulfiiric acid (Section 9.6B), followed by separation of the ortho and para isomers. 

STEP 2 Oxidation of the benzylic carbon, using chromic acid (Section 9.4). 

STEP 3 Reduction of the nitro group, either using H2 in the presence of a transition metal catalyst or using Fe, Sn, or Zn in the presence of aqueous HCl (Section 10.6). 

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