Amines are characterized by one to three alkyl groups being bonded to a central
nitrogen atom (i.e. R-NH2, R-NH-R', R-N(-R')-R''). The alkyl groups
need not be the same (indicted by the ', or '' behind the R), and may contain
other functional groups. The chemistry of these amines are all basically the same,
depending on the polarization of the C-N bond, and the lone pair of electrons
on the N. The three types of amines are designated as: primary (one
alkyl group); secondary (two alkyl groups); or tertiary
(three alkyl groups). Unfortunately there are several ways to name amines
depending on how many alkyl groups are attached to the nitrogen atom, or the presence
of additional functional groups.
1) Primary Amines:
There are two basic methods for naming simple primary amines, the first is to
name it as an alkyl amine (note the spaces between the words), and
the second as an alkanamine (note, the terminal e of the alkane
root is dropped).
Examples naming simple amines:
* Because the suffix here is -diamine which starts with a consonant,
the terminal -e of the alkane name is retained.
2) Secondary Amines:
The longest chain of carbons takes the root name (alkyl amine or alkanamine)
and the other chain becomes a substituent, located in the chain as being
attached to the N. The N is considered to be a lower locant than
numerical locants, and so is placed ahead of them. When the two alkyl groups
are the same it can also be named as a dialkyl amine.
Examples naming simple secondary amines:
3) Tertiary Amines:
Similar to the secondary amines, the longest chain of carbons takes the root name
(alkyl amine or alkanamine) and the other chains become substituents located on
the N. In this case, with two substituents on the N atom it will become
a N,N- amine. When the three alkyl groups are the same it can be named
as a trialkyl amine.
Examples naming simple tertiary amines:
Amines as Substituents:
In more complex molecules with multiple substituents, or ones containing
higher priority functional groups, the amine is named as an amino-
substituent. It is located by numbering the longest chain of carbons (containing
the functional groups of interest) and locating the NH2 group
by this numbering scheme (if the amino group is the highest priority group,
it should have the lowest possible number). Secondary and tertiary amines
are named by the above conventions.
A few examples of naming amines as substituents:
Tutorial Quiz: Amines
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