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

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Answer 1 · 2015-08-25T14:41:11

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

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

Structure

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

The ethyl group is on $C-2$ $"C-2"$ , and the sec-butyl group is on $C-5$ $"C-5"$ .

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 $C-3$ $"C-3"$ and on $C-7$ $"C-7"$ , and an ethyl group on $C-4$ $"C-4"$ .

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