Amines Chapter 20

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Amines Chapter 20

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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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Examples
Amines are much more polar, than hydrocarbons,
especially in acidic conditions
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Priority of citation -COOH gt -CHO gt -OH gt -NH2 gt
CC
The atom of N has the trigonal pyramid or

trigonal planar geometry (favored by conjugation)
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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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Amines are typical bases due to the lone electron
pair at nitrogen
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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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3. Alkylation of amines
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More examples of alkylation
4. Reductive amination
This reaction provides an efficient approach to
primary and secondary amines
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Borch reduction (one-step reductive amination)
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Borch reduction is also efficient to synthesize
tertiary amines
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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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As opposed to alkylation, acylation efficiently
produces all types of amides, because amides are
weaker nucleophiles, than the starting amines,
and do not react further
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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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Because of the steric hindrance, created by the
bulky trimethylammonium group, the reaction
proceeds against the Zaitsevs rule
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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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A standard sequence of protection-deprotection
allows to synthesize p-nitroaniline in a high
yield
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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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Examples
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The reaction does not yield a product for
alkylamines, however, nitrosation can occur at
an aryl substituent
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Reactions of diazonium salts with loss of nitrogen
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Reactions of diazonium salts without loss of
nitrogen
Diazonium salts also act as weak electrophiles
with phenols, and produce a vast variety of
azo-dyes. Many of these dyes are acid-base
indicators.
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Outline 1. Structure, nomenclature and physical
properties of amines 2. Acidity and basicity of
amines 3. Alkylation of amines 4. Reductive
amination 5. Acylation of amines 6. Hoffmann
elimination 7. Electrophilic reactions of
aniline 8. Reaction of amines with nitrous acid.
Diazonium salts 9. Synthesis of amines
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Gabriel synthesis of primary amines
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Curtius rearrangement
Example
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Hoffmann rearrangement (an
alternative way to produce an isocyanate)