Page 160 - Pharm.Org.Chem I 05-PC101 (1)

Polysubstituted Derivatives of Benzene

• The descriptors ortho, meta, and para cannot be used when
naming an aromatic ring bearing three or more substituents.

• In such a case, locants are required. That is, each substituent is
designated with a number to indicate its location on the ring.

• When naming a polysubstituted benzene ring, we will follow
these steps:

1. Identify and name the parent.
2. Identify and name the substituents.
3. Assign a locant to each substituent.
4. Arrange the substituents alphabetically

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Nomenclature of benzene derivatives

3,5-Dichlorobenzenesulfonic acid 2-Bromo-5-nitrotoluene 2,4,6-Trinitrotoluene
Explosive TNT

4-Ethyl-5-hydroxy-2-methylbenzoic acid 2,4,6-Trinitrophenol
Explosive

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