Download 18 Amines

General, Organic, and
Biological Chemistry
Fourth Edition
Karen Timberlake
Chapter 18
Amines and Amides
18.1
Amines
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Lectures
Amines



Amines are derivatives of ammonia (NH3).
In the IUPAC name for amines, the e in the
corresponding alkane name is replaced with
amine.
When the amine has a chain of three or more
carbon atoms, it is numbered to show the position
of the –NH2 group and any other substituents.
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Chapter 18, Section 1
2
Guide to IUPAC Naming of Amines
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Chapter 18, Section 1
3
Naming the Longest Carbon
Chain
 Name the longest carbon chain bonded to the N atom
by replacing the e of its alkane name with amine.
 Here, the longest carbon chain bonded to the N atom
has four carbon atoms, which is named by replacing
the e in the alkane name with amine to give
butanamine.
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Chapter 18, Section 1
4
Numbering the Carbon Chain
 The N atom in the amine group is attached to carbon
1 of butanamine.
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Chapter 18, Section 1
5
Alkyl Groups Attached to the N
Atom
 Any alkyl group attached to the N atom is indicated
by the prefix N- and the alkyl name, which is placed
in front of the amine name.
 Alkyl groups attached to the N atom are listed
alphabetically.
The IUPAC name is N-methyl-1-butanamine.
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Chapter 18, Section 1
6
Naming Common Amines
Common amines are named with common names as
alkylamines.
List the names of the alkyl groups bonded to the N atom
in alphabetical order in front of amine.
Ethylamine
Dimethylamine
Ethyldimethylamine
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Chapter 18, Section 1
7
Learning Check
Give the common and IUPAC names, and classify each as primary,
secondary, or tertiary.
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Chapter 18, Section 1
8
Solution
A.
STEP 1 Name the longest carbon chain bonded to the N
STEP 1 atoms as alkanamines by replacing e of the
STEP 1 alkane name with amine.
Propanamine
STEP 2 Number the carbon chain to show the position of
STEP 2 the amine group and any substituents.
CH3—CH2 —CH2—NH2
3
2
1
Propylamine (common), 1°
1-Propanamine (IUPAC)
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Chapter 18, Section 1
9
Solution (continued)
B.
STEP 1 Name the longest carbon chain bonded to the N
STEP 1 atoms as alkanamines by replacing e of the
STEP 1 alkane name with amine.
ethanamine
STEP 2 Number the carbon chain to show the position of
STEP 2 the amine group and any substituents.
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Chapter 18, Section 1
10
Solution (continued)
B.
STEP 3 In a secondary or tertiary amine, use the prefix
STEP 3 N- to name groups attached to the N atom.
Ethyldimethylamine (common),
N,N-Dimethylethanamine (IUPAC), 3°
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Chapter 18, Section 1
11
Naming Compounds with Two
Functional Groups

When a compound contains more than one functional group,
we need to identify which group is used as the name of the
compound and which group is named as the substituent.

According to the IUPAC rules, an oxygen-containing group will
have priority over an —NH2 group.

As a result, the —NH2 group is named as the substituent,
amino.
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Chapter 18, Section 1
12
Aromatic Amines
The amine of benzene


is called aniline.
may have alkyl groups attached to N that use the prefix N- and the alkyl
name.
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Chapter 18, Section 1
13
Learning Check
Give the common and IUPAC names for each of the following:
A.
B.
NH2
C.
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Chapter 18, Section 1
14
Solution
Ethylmethylamine(common);
N-methylethanamine
A.
B.
Butylethylmethylamine (common);
N-ethyl-N-methyl-1-butanamine
NH2
C.
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Aniline
Chapter 18, Section 1
15
Classification of Amines
Amines are classified as primary, secondary, or tertiary.

In a primary (1) amine, one carbon group is bonded to the
nitrogen atom.

A secondary (2) amine has two carbon groups.

A tertiary (3) amine has three carbon groups.
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Chapter 18, Section 1
16
Properties of Amines
 Amines contain polar N—H bonds, which allow
primary and secondary amines to form hydrogen
bonds with water.
 Nitrogen is not as electronegative as oxygen, which
results in weaker hydrogen bonds as compared to
those found in alcohols.
Please insert Figure of hydrogen bonds here;
Pg 646
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Chapter 18, Section 1
17
Solubility in Water
 Amines are soluble in water
if they have 1 to 6 carbon
atoms.
 Generally, 1° amines are
most soluble while 3°
amines are least soluble
because the N atom in
smaller amines forms
hydrogen bonds with the
polar O—H bond in water.
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Chapter 18, Section 1
18
Learning Check
Consider the following compounds:
1) CH3—CH2—CH2—NH2
2) CH3—CH2—NH—CH3
3) CH3—CH2—CH2—CH3
A. Which compound has the highest boiling point?
B. Which compound(s) is/are soluble in water?
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Chapter 18, Section 1
19
Solution
Consider the following compounds:
1) CH3—CH2—CH2—NH2
2) CH3—CH2—NH—CH3
3) CH3—CH2—CH2—CH3
A. Which compound has the highest boiling point?
1) CH3—CH2—CH2—NH2
B. Which compound(s) is/are soluble in water?
1) CH3—CH2—CH2—NH2
2) CH3—CH2—NH—CH3
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Chapter 18, Section 1
20
Heterocyclic Amines
A heterocyclic amine
 is a cyclic organic compound.
 has a five- or six-atom ring.
 contains one or more nitrogen atoms.
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Chapter 18, Section 1
21
Heterocyclic Amines in Nature
Heterocyclic amines,
 such as purine and pyrimidine rings are found
in DNA and RNA.
 like piperidine, are found in black pepper.
 with two or three double bonds, have aromatic
properties similar to benzene.
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Chapter 18, Section 1
22
Learning Check
Identify the following heterocyclic amines:
A.
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B.
C.
N
N
N
H
H
H
Chapter 18, Section 1
23
Solution
Identify the following heterocyclic amines:
A.
B.
N
N
N
H
H
H
Piperidine
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C.
Pyrrolidine
Chapter 18, Section 1
Pyrrole
24
Alkaloids
Alkaloids are
 physiologically active nitrogen-containing
compounds.
 produced by plants.
 used as stimulants, anesthetics, and antidepressants.
 often habit forming.
Nicotine is an alkaloid.
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Chapter 18, Section 1
25
Caffeine
Caffeine
 is a stimulant of the central nervous system.
 is found in coffee beans, tea, chocolate, and soft
drinks.
 contains an imidazole ring.
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Chapter 18, Section 1
26
Alkaloids Related to Morphine
Alkaloids,
 such as morphine and codeine, are produced by the
poppy and have been used for centuries as painkillers.
 such as heroin and codeine, are modifications of
morphine.
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Chapter 18, Section 1
27
Synthesizing Drugs:
Pharmacology
Areas of pharmacology research
 design drugs, such as procaine, lidocaine, and
Demerol, that retain some of the characteristics of
alkaloids.
 modify the structures of cocaine and morphine to
produce anesthesia, but without the addictive side
effects.
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Chapter 18, Section 1
28
Amides
In amides, an amino group(–NH2) replaces the –OH
group of carboxylic acids.
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Chapter 18, Section 1
29
Naming Amides: IUPAC
In both the IUPAC and the common names of amides,
amides are named by dropping the -ic acid or -oic acid
ending of the corresponding carboxylic acid and adding
the suffix amide.
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Chapter 18, Section 1
30
IUPAC Names of Amides
Write the IUPAC name for
STEP 1 Determine the alkane name of the carbon chain
in the carboxyl portion and replace e with amide.
butanamide
STEP 2 Name each substituent on the N atom using the
prefix N- and the alkyl name.
N-ethylbutanamide
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Chapter 18, Section 1
31
Examples of IUPAC and Common
Names
N-Methylethanamide (IUPAC)
N-Methylacetamide (common)
—
O H
║
CH3—CH2—C—N—CH2—CH3
N-Ethylpropanamide (IUPAC)
N-Ethylpropionamide (common)
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Chapter 18, Section 1
32
Learning Check
Write the IUPAC name for the following:
O CH2—CH3
║ │
CH3—CH2—CH2—CH2—C—N—CH2—CH3
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Chapter 18, Section 1
33
Solution
STEP 1 Determine the alkane name of the carbon chain
in the carboxyl portion and replace e with amide.
pentanamide
STEP 2 Name each substituent on the N atom using the
prefix N- and the alkyl name.
N,N-diethylpentanamide
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Chapter 18, Section 1
34
Aromatic Amides
 The amide of benzene is named benzamide.
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Chapter 18, Section 1
35
Learning Check
Draw the condensed structural formulas of the
following amides.
A. pentanamide
B. N-methylbutyramide
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Chapter 18, Section 1
36
Solution
Draw the condensed structural formulas of the
following amides.
A. pentanamide
B. N-methylbutyramide
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Chapter 18, Section 1
37
Classification of Amides
 Amides are classified according to the number of
carbon atoms bonded to the nitrogen atom.
Primary (1)
Secondary (2) amide
Tertiary (3) amide
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Chapter 18, Section 1
38
Learning Check
Give the common and IUPAC names for the following
amides, and classify them as primary, secondary, or
tertiary.
A.
B.
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Chapter 18, Section 1
39
Solution
Give the common and IUPAC names for the following
amides, and classify them as primary, secondary, or
tertiary.
Butryamide (common)
butanamide (IUPAC)
primary (1)
A.
B.
N-Ethyl-N-methylacetamide (common) (3)
N-ethyl-N-methylethanamide (IUPAC), tertiary
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Chapter 18, Section 1
40
Melting Points of Amides
Amides
 that are primary and secondary, form hydrogen
bonds and have high melting points.
 that are tertiary (no H on N), do not form hydrogen
bonds and have lower melting points.
Insert table 18.2 here, Pg 657
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Chapter 18, Section 1
41
Solubility of Amides in Water
Primary, secondary, and
tertiary amides with 1 to 5
carbon atoms
 form hydrogen bonds with
water.
 are soluble in water.
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Chapter 18, Section 1
42
Some Amides in Health and
Medicine (continued)
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Chapter 18, Section 1
43
Neurotransmitters
 A neurotransmitter is a chemical compound
that transmits an impulse from a nerve cell to
a target cell, such as another nerve cell, a
muscle cell, or a gland cell.
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Chapter 18, Section 1
44
Amine Neurotransmitters:
Acetylcholine
 Neurotransmitters contain N atoms as amines and alkyl
ammonium ions.
 Acetylcholine (ACh) was the first neurotransmitter to
be identified.
 Neurotransmitters communicate between the
nervous system and the muscle.
 When stimulated, it releases into the synapse where
it binds to muscle cell receptors causing the muscles
to contract.
Please insert acetylcholine to acetate reaction here (Pg 662)
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Chapter 18, Section 1
45
Dopamine
 Dopamine is produced in the nerve cells of
the midbrain and acts as a natural stimulant
to give us energy and feelings of enjoyment.
 Cocaine and amphetamine block the
reuptake of dopamine resulting in a longer
lifetime in synapse.
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Chapter 18, Section 1
46
Norepinephrine and Epinephrine
 Norepinephrine (noradrenaline) and
epinephrine (adrenaline) are hormonal
neurotransmitters that play a role in sleep,
attention and focus, and alertness.

Epinephrine is synthesized from Norepinephrine.
 Both are normally produced in the adrenal
glands.

Both are highly produced during the fight-or-flight
response.
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Chapter 18, Section 1
47
Serotonin
 Serotonin helps us relax, sleep deeply and
peacefully, think rationally, and it provides us
a feeling of well-being and calmness.
 Serotonin is synthesized from the amino acid
tryptophan.
 Low serotonin levels may be associated with
depression, anxiety disorders, etc.

Prozac and Paxil (antidepressant drugs) are
selective serotonin reuptake inhibitors (SSRIs).
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Chapter 18, Section 1
48
Histamine
Histamine
 is synthesized in the nerve cells in the
hypothalamus from the amino acid, histidine.
 is produced by the immune system in response
to pathogens and invaders, or injury.
 When histamine combines with histamine
receptors, it produces allergic reactions.
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Chapter 18, Section 1
49
Amino Acid Neurotransmitters
Glutamate
 is the most abundant neurotransmitters in the
nervous system.
 stimulates the synthesis of nitrogen oxide
(NO).
 Too much glutamate in the spinal cord
causes degeneration of nerve cells (known as
Lou Gehrig’s disease).
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Chapter 18, Section 1
50