IUPAC Nomenclature of a Branched Alkane

Q11. What is the name of the following compound?

Given structure:

CH3–CH–CH2CH2CH(CH3)2 | CH2CH3

Background

Topic: IUPAC Nomenclature of Alkanes

This question tests your ability to apply the IUPAC rules for naming branched alkanes, including identifying the longest carbon chain, numbering the chain to give substituents the lowest possible numbers, and naming and ordering substituents correctly.

Key Terms and Concepts:

• Longest Chain: The parent hydrocarbon is the longest continuous chain of carbon atoms.

• Substituents: Groups attached to the main chain (e.g., methyl, ethyl).

• Numbering: Number the chain from the end nearest a substituent to give the lowest possible numbers to the substituents.

• Naming: List substituents alphabetically, use prefixes (di-, tri-) if needed, and indicate their positions with numbers.

Step-by-Step Guidance

1. Identify the longest continuous carbon chain in the structure. Count the number of carbons in this chain to determine the parent name (e.g., pentane, hexane, heptane, etc.).

2. Number the main chain from the end closest to the first branching point, so that the substituents get the lowest possible numbers.

3. Identify and name each substituent (e.g., methyl, ethyl, isopropyl) and determine the carbon number to which each is attached.

4. Combine the substituent names and numbers with the parent chain name, listing substituents alphabetically and using prefixes if there are multiples of the same group.

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