Question

What is the IUPAC name of ${\mathrm{CH}}_3\mathrm{CH}=\mathrm{CHC}\left(\mathrm{Br}\right){\left({\mathrm{CH}}_3\right)}_2$?

Answer 1

IUPAC Nomenclature

• "In order to clearly identify the compound, a systematic method of naming has been developed and is known as the IUPAC (Internation Union of Pure and Applied Chemistry) system of nomenclature."

Rules of IUPAC nomenclature

• The structure of ${\mathrm{CH}}_3\mathrm{CH}=\mathrm{CHC}\left(\mathrm{Br}\right){\left({\mathrm{CH}}_3\right)}_2$ is as follows,
• 

Determination of Root Word

Select the continuous chain with the maximum number of carbon atoms

Here the chain is having 5 carbon atoms, hence root word will be “Pent”

Determination of names and positions of Locants

There are two substituents at the fourth position, 4-Bromo, and 4-methyl.

Determination of Suffix

As this compound is unsaturated, the suffix will be “ene”.

• Hence, the IUPAC name of ${\mathrm{CH}}_3\mathrm{CH}=\mathrm{CHC}\left(\mathrm{Br}\right){\left({\mathrm{CH}}_3\right)}_2$ is 4-bromo-4-methyl-pent-2-ene.