Aromatic Nomenclature

Monosubstituted Benzenes n Monosubstituted aromatics are named using -benzene as the parent name.

Monosubstituted Benzenes n Alkyl substituted benzenes are named according to the chain length of the alkyl group. n Six Carbons or Fewer. Named as alkylbenzene. n ethylbenzene

Monosubstituted Benzenes n Six Carbons or More. Named as phenyl-substituted alkane. n 4-phenylnonane

Monosubstituted Benzenes n The benzyl group is another common name for a monosubstituted methylbenzene (toluene). n benzylbromide

Monosubstituted Benzenes n There are a number of nonsystematic (common) names which you should learn for the monosubstituted benzenes. n These common names are used when naming aromatic compounds.

Monosubstituted Benzenes

Disubstituted Benzenes n Disubstituted benzenes can be named one of two ways. Each method describes the relationship of the two groups on the six membered aromatic ring. ä Systematic numbering of the aromatic ring. ä Using the prefixes ortho-, meta-, or para-. n The common names for monosubstituted benzenes can be used as parent names for disubstituted aromatics.

Disubstituted Benzenes n ortho-=o-= 1,2-disubstituted n meta-=m-= 1,3-disubstituted n para-=p-= 1,4-disubstituted

Disubstituted Benzenes n There are a number of nonsystematic (common) names for disubstituted benzenes that you should be familiar with.

Polysubstituted Benzenes n Polysubstituted benzenes are named by numbering the position of each substituent on the ring. n The numbering is carried out to give the substituents the lowest possible numbers. n The substitutents are listed in alphabetical order when writing the name. n Common names of the monosubstituted benzenes can also be used as parent names for polysubstituted aromatics.

Polysubstituted Benzenes 4-Bromo-2-ethyl-1-nitrobenzene

Polycyclic Aromatic Hydrocarbons (PAH)

n Benzo[a]pyrene is an important PAH which has been studied extensively. n Benzo[a]pyrene is found in chimney soot, barbecued meat and cigarette smoke. n Metabolites of benzo[a]pyrene form adducts with DNA.

Polycyclic Aromatic Hydrocarbons (PAH)