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Nomenclature of Aromatic compounds

When a benzene ring is a substituent, the term phenyl is used (for C6H5-)

You may also see “Ph” or “f” in place of “C6H5”

“Benzyl” refers to “C6H5CH2-”

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Benzene is the parent name for some monosubstituted benzenes; the substituent name is added as a prefix.

The C6H5- group is called phenyl when it is a substituent

A hydrocarbon with a saturated chain and a benzene ring is named by choosing the larger structural unit as the parent

If the chain is unsaturated then it must be the parent and the benzene is then a phenyl substituent

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For other monosubstituted benzenes, the presence of the substituent results in a new parent name.

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When two substituents are present their position may be indicated by the prefixes ortho, meta, and para (o, m and p) or by the corresponding numerical positions.

If the two groups on the benzene ring are different, alphabetize the names of the substituents preceding the word benzene.

If one substituent is part of a common root, name the molecule as a derivative of that monosubstituted benzene.

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o-bromochlorobenzene m-fluoronitrobenzene

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For three or more substituents on a benzene ring: Number to give the lowest possible numbers around the ring. Alphabetize the substituent names. When substituents are part of common roots, name the

molecule as a derivative of that monosubstituted benzene. The substituent that comprises the common root is located at C1.

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Polynuclear Aromatic Hydrocarbons:

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Electrophilic Aromatic Substitution

Benzene does not undergo addition reactions like other unsaturated hydrocarbons, because addition would yield a product that is not aromatic.

Substitution of a hydrogen keeps the aromatic ring intact.

Halogenation, Alkylation, Nitration, and Sulfonation are the typical electrophilic aromatic substitution reactions.

1 -Specific Electrophilic Aromatic Substitution Reactions

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Examples:

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2 -Side-Chain Reactions of Aromatic Compounds

A) Halogenation of an Alkyl Side-Chain

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B) Oxidation of an Alkyl Side-Chain

hot

hot

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Disubstituted Benzenes: Orientation

Product ratio conclusion:40% ortho, 40% meta,

20% para

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Orientation and Reactivity Effects of Substitutions Y in Electrophilic Aromatic Substitution

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Examples:

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Homework1- Name the following compounds.

NO2

H3C

CH CH2

Cl

CCH2Cl

NO2

H3C

Cl

CH2CH3

CH2CH3

O2N

NO2

NO2

Br

COOH

O2NCH3 CH3

CH3

A) B) C) D)

E) F) G) H)

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2- Write the structures of the following compounds.A) p-NitroethylbenzeneB) 2,2-Dimethyl-1-phenylbutaneC) o-EhtylanilineD) 1,5-DimethylnaphthaleneE) 9-BromoanthraceneF) 2,4-DinitroflurorbenzeneG) 2-Benzyl-3-nitro-5-bromophenol

Br + H2SO4 ,SO3A)

COOH +B)H2SO4HNO3

COCH3 +C) Cl2FeCl3

OCH3 +D)AlCl3CH3Cl

3- Complete the following reactions.