Amines & Amides

Amines and Amides
Amine Structure and Properties
Amine Nomenclature
Heterocyclic Amines
Amine Sources
Basicity of Amines
Reactions of Amines
Some Important Amines
Amides
Properties of amines
Nitrogen is very electronegative.
Results in
• N-H bond being very polar.
• Hydrogen bonding being possible.
• High boiling points.
• Amines being organic bases.
Nomenclature
When a primary amine present with another
functional group: Use same approach as with
any branch or substituent.
HO-CH2CHCH2CH2
| |
Br NH2
4-amino-2-bromo-1-butanol
Amines
Amines
bases, substituted ammonia
biologically significant: amino acids,
DNA, RNA bases, alkaloids
General formula
• Primary amine R-NH 2
• Secondary amine R 2 -NH
• Tertiary amine R3-N
• Quarternary R 4 -N + X -
Primary amines.
Amine nomenclature
Locate longest carbon chain that contains the -NH2
group.
Treat -NH2 group as a branch with the name amino.
Assign location so that the lowest possible number
is used.
If other branches are present, number and name as
with other compounds.
Alternate system uses ‘amine’ ending instead of
amino branch name.
NOTE: The amino group is treated the same as a
halogen, methyl, ethyl, ....
CH3CH2CH2NH2
1-aminopropane
Examples
2-aminohexane
NH2
|
CH3CH2CH2CH2CHCH3
NH2
|
CH3-CH-CH3
2-aminopropane

Nomenclature
Secondary and Tertiary amines
• Treat additional branches as a branch on
the nitrogen.
• Base name is based on longest chain that
contains the amine.
• Name other chain as alkyl substituent on
the nitrogen.
• Use N- at front of a branch name
indicates that substituent is on the
nitrogen.
Examples
(CH3CH2)2NCH3
N-ethyl-N-methylaminoethane
CH3-CH-CH2-NH2
|
NH2
1,2-diaminopropane
CH3
CH3-C-CH-CH3
|
H2N OH
3-amino-3-methyl-2-butanol
Nomenclature
Some common names
methyl amine CH 3 -NH 2
dimethyl amine CH 3 -NH-CH 3
ethyl amine CH 3 -CH 2 -NH 2
methyl ethyl amine CH3-NH-CH2-CH3
Common approach is to give alkyl name with
amine ending.
|
|
Examples
CH3CH2CH2-NH-CH3
N-methyl-1-aminopropane
N
CH 3
CH 3
N,N-dimethylaminocyclohexane
Nomenclature
Many aromatic amines have special names
that have been accepted as IUPAC names.
NH 2
NH 2
CH 3
NH 2
CH 3
NH 2
aniline p-toluidine o-toluidine m-toluidine
Heterocyclic amines
Ring structures that have one or more
nitrogen contained within the ring.
N
H
N
Pyrrole Pyridine
CH 3

H 3 CO
Heterocyclic amines
N
H
N N
M +
Indole Porphyrin
Amines of medical interest
Many amines have ‘interesting’ medical uses.
Analgesics
H
O
||
NH-C-CH3
|
|
OCH 2 CH 3
Phenacetin Acetaminophen
(APC tablets) (Tylenol)
N
N
O
||
NH-C-CH3
|
|
OH
Heterocyclic drugs
C H
O
N
O
CH 3
Cocaine
O
C
H 3 CH 2 C
O
C
N
N
H
CH 2 CH 3
N
CH 3
lysergic acid
diethylamide (LSD)
HO
Heme
Medically important amines
Amphetamines
Stimulate central nervous system.
benzidrine
Barbituates
Depress central nervous
system.
barbital
O
HN CH 3
CH
C CH3
H2 N
N
O
O
CH 2 CH 3
CH 2 CH 3
Neurotransmitters
Chemicals that pass signals
between nerve cells.
N
H
Serotonin
CH 2 CH 2 NH 2
CH3 N +
CH 3
O
H 3 C CH 2 CH 2 O
C
Acetylcholine
CH 3

Viagra
Production of amines
Laboratory sources
from amides
O
||
CH3CH2CH2-C-NH2 from nitro compounds
NO 2
[R]
Formation of Amides
Amide -
[R]
NH 2
CH 3 CH 2 CH 2 CH 2 -NH 2
Reactions of amines
amine derivative of a carboxylic acid.
General formula
O
||
R-C-NH2
Sources of amines
Industrial sources
Production from ammonia and an alcohol.
NH 3 + CH 3OH
CH 3NH 2 + NH 3
(CH 3)NH + NH 3
Al 2O 3
heat
Al 2O 3
heat
Al 2O 3
heat
CH 3NH 2 + H 2O
(CH 3) 2NH + H 2O
(CH 3) 3N + H 2O
Basicity of amines
Amines react with acids much like ammonia.
H
|
R-N:
|
H
+ HCl
H
|
R-N-H + Cl- H |
+
Results in salt formation.
Amide nomenclature
Similar to carboxylic acid.
Drop -oic acid ending and replace with amide
O
||
CH3-CH2-C-NH2
Propanamide
O NH2 C
Benzamide

Preparation of amides
Production from a carboxylic acid
O
||
CH3-CH2-C-OH
NH3 heat
O
||
CH3-CH2-C-NH2
Production from an acid chloride
C
O
Cl
NH 3
heat
Amino acids
C
O
NH 2
We rely on amide bonds when we build
proteins from amino acids.
General
structure
of an
amino acid.
H
R C
NH 2
C
O
OH
NOTE: We will cover this in
much more detail in Ch. 19.
Acid group
Base group
They are too close
to each other to
form an amide.
Nylon
If we have a diamine and a diacid chloride, we can produce
a polymer using amide bonds. Nylon is an example.
O
O
hexamethylenediamine
n Cl C (CH2 ) 4 C Cl + n H2N (CH2 ) 6 NH2 adipoyl chloride
O O
Amide
linkage
H 2 N
* C
H H
(CH2 ) 4 C N (CH2 ) 6 N *
n
polyamide nylon
The peptide bond
Proteins are polymers made up of amino acids.
Peptide bond (amide linkage)
How the amino acids are linked together
to form a protein.
H
C
R
O
C
H
OH H2N C C
R'
O
H 2 N
OH
H
C
R
O
C
H
H
N C C
R'
O
OH