Question

Give IUPAC names for the following compounds:

(a)

Short answer

3-Methyl-2,4-hexa-diene

Step-by-step solution

IUPAC (International Union for Pure and applied Chemistry)

IUPAC is an International body that represents chemistry and science. Its aim is to unite science globally. IUPAC devised a system of naming various chemical compounds systematically which is acceptable all over the world. It is constituted by 4 parts,

IUPAC name $\mathbf{=}\mathbf{Locant}\mathbf{+}\mathbf{Prefix}\mathbf{+}\mathbf{Parent}\mathbf{+}\mathbf{Suffix}$

Locant tells us the position of the substituent, prefix tell us what the substituent is, parent suggest the length of the carbon chain (2,3,4 and so on) and the primary functional group is identified by the suffix part.

There are some rules that must be followed in order to start naming a compound which you’ll get to understand as we deal with the question.

Numbering of the given compound

First we look for the longest parent chain of carbon, in our case it is 6 carbon chain, that means hex. Now, start numbering carbon atoms from the side where double bond is near, i.e., from left end. A methyl substituent at position 3 and two double bonds at position 2 and 4.

Naming of the given compound

Following, IUPAC name $\mathbf{=}\mathbf{Locant}\mathbf{+}\mathbf{Prefix}\mathbf{+}\mathbf{Parent}\mathbf{+}\mathbf{Suffix}$rule,

While naming the compounds, you should also keep in mind to use di, tri etc before the substituents ( if more than one of same kind)or double bonds to indicate their number and use numbers to indicate their location.

The name of the compound is 3-methyl-2,4-hexa-diene.