Download Aromatic Nomenclature

Aromatic
Nomenclature
Monosubstituted Benzenes

Monosubstituted aromatics are named using
-benzene as the parent name.
F
Fluorobenzene
NO 2
Nitrobenzene
CH 2CH 3
Ethylbenzene
Monosubstituted Benzenes



Alkyl substituted
benzenes are named
according to the
chain length of the
alkyl group.
Six Carbons or
Fewer. Named as
alkylbenzene.
ethylbenzene
CH 2CH 3
Monosubstituted Benzenes


Six Carbons or
More. Named as
phenyl-substituted
alkane.
4-phenylnonane
phenyl- group
CH 3CH 2CH 2
CHCH 2CH 2CH2CH 2CH 3
Monosubstituted Benzenes


The benzyl group is
another common
name for a
monosubstituted
methylbenzene
(toluene).
benzylbromide
CH2
benzyl- group
CH 2Br
Monosubstituted Benzenes
There are a number of nonsystematic
(common) names which you should
learn for the monosubstituted benzenes.
 These common names are used when
naming aromatic compounds.

Monosubstituted Benzenes
CH 3
Toluene
(Methylbenzene)
OH
Phenol
(hydroxybenzene)
CH 3
H
C
CHCH 3
Cumene
(Isopropylbenzene)
Styrene
(vinylbenzene)
NH 2
Aniline
(aminobenzene)
CH 2
CN
Benzonitrile
(cyanobenzene)
O
CHO
COOH
CH 3
Benzaldehyde
Benzoic acid
Acetophenone
Disubstituted Benzenes


Disubstituted benzenes can be named one of
two ways. Each method describes the
relationship of the two groups on the six
membered aromatic ring.
 Systematic numbering of the aromatic ring.
 Using the prefixes ortho-, meta-, or para-.
The common names for monosubstituted
benzenes can be used as parent names for
disubstituted aromatics.
Disubstituted Benzenes
NO 2
Cl
o-diiodobenzene
m-dinitrobenzene
Cl
1,2-diiodobenzene
1,3-dinitrobenzene
p-dichlorobenzene
I
I
NO 2
1,4-dichlorobenzene



orthometapara-
=
=
=
omp-
=
=
=
1,2-disubstituted
1,3-disubstituted
1,4-disubstituted
Disubstituted Benzenes

There are a number of nonsystematic
(common) names for disubstituted benzenes
that you should be familiar with.
CH 3
CH 3
xylene
CH 3
OH
cresol
Polysubstituted Benzenes




Polysubstituted benzenes are named by
numbering the position of each substituent on
the ring.
The numbering is carried out to give the
substituents the lowest possible numbers.
The substitutents are listed in alphabetical
order when writing the name.
Common names of the monosubstituted
benzenes can also be used as parent names
for polysubstituted aromatics.
Polysubstituted Benzenes
Br
OH
Cl
CH 2CH 3
NO 2
4-Bromo-2-ethylnitrobenzene
4-Bromo-2-ethyl-1-nitrobenzene
NOT
1-Bromo-3-ethyl-4-nitrobenzene
Br
5-Bromo-2-chlorophenol
Polycyclic Aromatic
Hydrocarbons (PAH)
Naphthalene
Pyrene
Anthracene
Phenanthrene
Benzo[a]pyrene
Polycyclic Aromatic
Hydrocarbons (PAH)
Benzo[a]pyrene is an important PAH
which has been studied extensively.
 Benzo[a]pyrene is found in chimney
soot, barbecued meat and cigarette
smoke.
 Metabolites of benzo[a]pyrene form
adducts with DNA.

Polycyclic Aromatic
Hydrocarbons (PAH)
Liver
Enzymes
epoxide
hydrolase
HO
O
OH
O
N
N
R
NH
N
NH
O
O
HO
DNA
HO
+
HO
HO
OH
OH
OH