# Draw 2-ethyl-5-sec-butylheptane and what is the correct iupac name?

Aug 25, 2015

The correct IUPAC name is 4-ethyl-3,7-dimethylnonane.

#### Explanation:

The structure of 2-ethyl-5-sec-butylheptane is

The 7-carbon chain is the horizontal zig-zag line.

The ethyl group is on $\text{C-2}$, and the sec-butyl group is on $\text{C-5}$.

But the longest continuous chain is the 9-carbon chain that runs from the top to the lower right.

We start numbering from the lower right, because that end is closer to more substituents — it gives us lower numbers.

There are methyl groups on $\text{C-3}$ and on $\text{C-7}$, and an ethyl group on $\text{C-4}$.

The IUPAC name is therefore 4-ethyl-3,7-dimethylnonane.