Name the iupac name of this compound

The compound contains a carboxyl group ($-\text{COOH}$), which means it is a carboxylic acid. The carbon atom of the carboxyl group is always designated as C1.

Starting from the carboxyl carbon (C1):

At C3, there are two branches: a methyl group ($\text{CH}_3$) and a propyl group ($\text{CH}_2\text{CH}_2\text{CH}_3$). To find the longest chain, we extend through the branch with more carbons. The propyl group has 3 carbons, while the methyl group has 1 carbon.
So, the main chain continues through the propyl group:

This gives a 6-carbon chain. Therefore, the parent acid is hexanoic acid.

On the 6-carbon chain, at position C3, there is a methyl group ($\text{CH}_3$) attached.

Combine the position and name of the substituent with the parent chain name.
The methyl group is at position 3. The parent chain is hexanoic acid.

The IUPAC name is 3-methylhexanoic acid.

The final answer is $\text{3-methylhexanoic acid}$