If in the given structure of a compound there are two chains with an equal number of carbon atoms how do you understand which is the parent chain?

1 Answer
Feb 1, 2016

You choose the chain that has more substituents.

Explanation:

Consider the molecule shown below.

Example

If you count from the left hand end and go up, there are 8 carbons in the chain.

The chain will have an isobutyl group at #"C4"#.

If you count from the left hand end and go straight across, there are 8 carbons in the chain.

The chain will have a methyl group at #"C2"# and a propyl group at #"C4"#.

The second choice has more substituents, so it becomes the parent chain for naming purposes.