Question

Write IUPAC name of the following compound: neopentyl bromide.

Answer 1

Hint: First draw the structure of the compound according to the given common name. Neo is used when three methyl groups are attached to the single carbon atom and iso is used when two methyl groups are attached.

Complete answer:
First let us understand some concepts related to this question:
a) Normal or “n”: It is used when all carbons form a continuous, unbranched (linear) chain.

Common Name: n-pentane
IUPAC Name: Pentane
b) Iso prefix is used when all carbons form a continuous chain except one.

Common Name: iso-pentane
IUPAC name: 2-methyl butane
c) Neo prefix is used when three methyl groups are attached.

Common Name: iso - pentyl
IUPAC name: 2,2 dimethylpropane
Now we are clear with these prefixes so let’s draw the structure now.
Neopentyl bromide:

Now keep in mind these important points while IUPAC naming:
- Find and name the longest carbon chain.
- Identify and name the groups which are attached to these chains.
- Now start numbering the chain consecutively, starting at the end nearest to the substituent group.
- Designate the location of each substituent group by an appropriate number and name.
- Now arrange the name, listing group according to alphabetical order.
- Halogen substituent as in this question can be easily named. By using the names like fluoro, chloro, bromo ,iodo.
Now we are clear with all rules, let's name the compound.
We will start numbering from the bromo group. There are two methyl groups attached to 2 carbon.
IUPAC Name:
1 Bromo-2, 2-dimethylpropane.

Note: Don’t forget to arrange the names in alphabetical order. Use words like di ,tri ,tetra for more than one group. Always choose the longest chain as the parent chain.