IUPAC Naming of a Branched Alkane (Structure Identification)

Q6. What is the correct IUPAC name of the structure shown?

Background

Topic: IUPAC Nomenclature of Alkanes

This question tests your ability to apply the rules of IUPAC nomenclature to name a branched alkane. You need to identify the longest continuous carbon chain, number the chain to give the substituents the lowest possible numbers, and name and order the substituents correctly.

Key Terms and Concepts:

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

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

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

• Alphabetical Order: List substituents in alphabetical order when writing the name.

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 that gives the substituents the lowest possible numbers. Assign a number to each carbon in the main chain.

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

4. Combine the substituent names and numbers, listing them in alphabetical order, and use prefixes (di-, tri-, etc.) if there are multiple identical substituents. Make sure to use commas between numbers and hyphens between numbers and words.

Try solving on your own before revealing the answer!