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CHAPTER 22 941 
 
 
22.56. Hydrazine releases the amine via two successive 
nucleophilic acyl substitution reactions (as shown), 
giving the following by-product: 
 
N
O
O
R
+
H2N NH2
NH
NH
O
O
N
N
O
O
NH2
H
R
H
H N
R
H
 
 
22.57. 
(a) The starting material is a secondary amine and the 
reagents indicate a Hofmann elimination. In the first 
step, two methyl groups are installed, converting the 
secondary amine into a quaternary ammonium ion. 
Then, treatment with aqueous silver oxide and heat 
results in cleavage of a C-N bond (thereby opening the 
ring) and formation of a double bond, as shown: 
 
 
 
(b) This is a Gabriel synthesis. Since the alkyl halide is 
ethyl bromide, the product is ethylamine: 
 
 
 
(c) The starting alkyl halide is converted into a nitrile 
upon treatment with sodium cyanide in a polar aprotic 
solvent (via an SN2 process). Hydrolysis of the nitrile 
with aqueous acid and heat gives a carboxylic acid, 
which is then converted into an acid chloride upon 
treatment with thionyl chloride. The acid chloride is 
then converted into an amide upon treatment with excess 
ammonia, via a nucleophilic acyl substitution reaction. 
 
 
 
(d) Treating benzene with a mixture of nitric and 
sulfuric acid results in nitration of the aromatic ring, 
giving nitrobenzene. Subsequent treatment of 
nitrobenzene with iron in aqueous acid (followed by 
basic work-up) results in reduction of the nitro group, 
giving aniline. Aniline is converted into a diazonium ion 
upon treatment with sodium nitrite and HCl, and the 
diazonium ion is converted into benzonitrile via a 
Sandmeyer reaction (with CuCN): 
 
 
 
 
 
 
 
 
 
 
 
22.58. The carbonyl group is converted into a dimethyl amino group via a reductive amination process. A Hofmann 
elimination then gives an alkene. The double bond cannot be formed at a bridgehead position (Bredt’s rule), so there is 
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