Question

The correct IUPAC nomenclature for the following compound is.

• A. 2 Methyl 5 oxohexanoic acid
• B. 2 Formyl 5 methylhexan 6 oic acid
• C. 5 Formyl 2 methylhexanoic acid
• D. 5 Methyl 2 oxohexan 6 oic acid

Answer 1

The Correct Option is A

The task is to determine the correct IUPAC name for the given compound image. Let's break down the steps for naming organic compounds according to IUPAC guidelines. 

1. Identify the longest carbon chain that contains the highest-priority functional group. In this case, it's a carboxylic acid, so the longest chain including the -COOH group becomes the parent chain. The parent chain consists of 6 carbon atoms, making it a hexanoic acid.
2. Number the carbon chain starting from the end nearest the functional group. Therefore, the carboxylic acid carbon will be carbon 1.
3. Identify and name substituents. In this structure, there is a methyl group attached to the second carbon and a keto (oxo) group on the fifth carbon.
4. Combine the names: \(2\) Methyl and \(5\) Oxo are the substituents on the hexanoic acid chain.

The correct IUPAC name is 2 Methyl 5 oxohexanoic acid. This name correctly reflects the structure, with substituents and functional groups in their correct order.

Rationale for ruling out other options:

• 2 Formyl 5 methylhexan 6 oic acid: A formyl group is not present in the structure; rather, it is an oxo group at the fifth position.
• 5 Formyl 2 methylhexanoic acid: Again, the formyl term is incorrect. Only an oxo group is present.
• 5 Methyl 2 oxohexan 6 oic acid: The positions of methyl and oxo groups are incorrectly assigned.

Thus, the option 2 Methyl 5 oxohexanoic acid is the correct answer.