Download 1-14 Amines Amides

Amines and Amides (1.7)
They can be viewed as having an amino group, an -NH2 group, attached to an alkane. This approach
is used for the IUPAC names.
Amines are designated as primary secondary and tertiary amines. 1 carbon, 2 carbons or 3 carbons
attached to the Nitrogen
IUPAC Names for Primary Amines
If you consider a primary amine to be an amino group attached to an alkane, you would simply name
it as you would an alkane derivative. This is the IUPAC method for naming these compounds.
This is an amine in which the nitrogen is bonded to
one alkyl group and to two hydrogen atoms.
Therefore it is a primary amine. The IUPAC name is
aminomethane because the amino group is attached
to a methane chain. (The common names are also
given here in brackets)
CH3-NH2
aminomethane (or methylamine)
C
This compound contains a chain of four carbon atoms
with an amino group bonded to the second one. Thus,
it is called 2-aminobutane.
C C C
N
H
H
2-aminobutane (or sec-butylamine)
C
For similar reasons this compound is named 1aminopropane,
C C
N
H
H
1-aminopropane (or propylamine)
C
and this one is named 2-aminopropane.
C
C
N
H
H
2-aminopropane (or isopropylamine)
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IUPAC Names for Secondary and Tertiary Amines
It is also possible to name secondary and tertiary amines (like those shown above) using the IUPAC
method. To do that, you need to know one additional aspect of the IUPAC methodology. That is using
the letter N to show the location of an alkyl group that is attached to the nitrogen atom.
First, you find and name the longest continuous carbon chain that has the nitrogen attached to it. With
ethylpropylamine that would be propane for the three-carbon chain.
C C
C
N
C
C
H
The parent is thus aminopropane. As the amino group is attached to the 1 carbon of the propane it is
1-aminopropane
Then there is the ethyl group. You have to add that to the name and show where it is attached. Since it
is attached to the nitrogen atom, you put N- rather than a number in front of ethyl, thus
N-ethyl-1-aminopropane.
Next example:
In this example, the longest continuous chain is an ethane chain with two carbon atoms.
C
C
C
N
C
Again, the nitrogen atom is attached to the number one carbon, so part of the name is 1-aminoethane.
Since there are two methyl groups attached to the nitrogen, we add N,N-dimethyl- to the front of the
name. Note each methyl group gets its own locator, thus there are two Ns in the name.
The IUPAC name for this compound is N,N-dimethyl-1-aminoethane.
The IUPAC method requires that you first select the longest carbon chain and name the amino groups
and other groups attached to that carbon chain. Show the location of each group attached to the
parent chain by using numbers. Then locate and name any additional groups attached to the nitrogen
atom. Show their location by the symbol N.
Drawing a Structure from a given Name
Coming up with the structure for an amine, given the name, is, of course, just the reverse of the
procedure for naming amines
IUPAC name,

write down the carbon chain as indicated,

then attach the amino and other groups to it as indicated,

then attach any additional groups to the nitrogen if indicated.

fill in the hydrogen atoms, remembering that each carbon atom has four bonds and each
nitrogen atom has three.
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Properties:
Strong unpleasant fishy ordours.
Polar (due to the amino group).
 Small, 1° and 2° amines are soluble in polar solvents (e.g. water). As the aliphatic
portion gets larger, their polarity decreases and they are less soluble in H2O.
 They have higher m.p and b.p. than nonpolar compounds of similar weight.
 Amines are less polar than alcohols. Therefore less soluble
3° amines are less polar that 1° and 2° amines.
 They cannot form the intermolecular hydrogen bonds that the others can.
 Thus, they have lower m.p., b.p., and water solubilities.
Do: 1,2 p.58
Reactions of Amines
Amines can act as bases and neutralize acids.
The products formed are an amide and H2O
H
e.g.
H C C
H
H
O
+
OH
H C
O
NH2
+
C C
N
H
H
H2O
CH3
ethanoic acid + amino methane → H2O + methylethanamide
Amides
Amides are formed through the reaction of ammonia (NH3) or amine with an acid.
Naming is simply replacing the –oic acid with “amide”. The -oic acid ALWAYS gets the –amide ending
This reaction is methyl amine and
ethanoic acid to produce
N-methyl ethanamide
Reactions: Focus on the type of components…primary, secondary, tertiary. Reactions we encounter are
amine + acid in a condensation reaction that leaves an amide and water.
Properties:
 Smaller amides are soluble in water
 Primary amides have higher MP/BP
Homework: 1,2 p. 60 and 1-6 p. 62
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