Question

The IUPAC name of $CH₃-CH(OH)-CH=C(CH₃)-CHO$ is ________.

• A. 4-hydroxy-1-methylpentanal
• B. 4-hydroxy-2-methylpent-2-en-1-al
• C. 2-hydroxy-4-methylpent-3-en-5-al
• D. 2-hydroxy-3-methylpent-2-en-5-al

Hint:

The IUPAC name of $CH3-CH(OH)-CH=C(CH3)-CHO$ is ____.

Answer 1

The Correct Option is B

Step 1: Parent Chain
The longest carbon chain contains the aldehyde group (-CHO), which is given priority (C1).
Step 2: Numbering
Numbering from the -CHO group: C1 is CHO, C2 has a methyl group, C3 is part of a double bond, and C4 has a hydroxyl group.
Step 3: Substituents
- Hydroxyl at C4 (4-hydroxy)
- Methyl at C2 (2-methyl)
Step 4: Name Assembly
The base is pent-2-en-1-al. Combining everything: 4-hydroxy-2-methylpent-2-en-1-al.
Final Answer: (B)