Answer
🔬 IUPAC Naming of Aromatic Compounds
🧪 Objective
To assign the correct IUPAC name to a substituted aromatic compound containing:
- A hydroxy group (–OH)
- An ethyl group
- A sec-butyl group
🔍 Step-by-Step Naming
1. Identify the Parent Compound
The molecule is based on phenol, which is benzene with an –OH group attached. The hydroxyl group takes priority and is assigned position 1.
2. Number the Ring
Number the ring to give the lowest locants to substituents. The optimal numbering is:
- –OH at position 1
- Ethyl group at position 2
- sec-Butyl group at position 5
3. Alphabetical Order of Substituents
Substituents are listed alphabetically (ignoring prefixes like sec- and tert-):
- Ethyl comes before sec-butyl
✅ Final IUPAC Name
5-sec-butyl-2-ethylphenol
🧠 Summary Table
| Feature | Detail |
|---|---|
| Parent Compound | Phenol |
| Main Functional Group | Hydroxy group (–OH) at C1 |
| Substituent 1 | Ethyl at C2 |
| Substituent 2 | sec-Butyl at C5 |
| Final Name | 5-sec-butyl-2-ethylphenol |
📘 Conclusion
- Phenol is used as the base name due to the –OH group on the aromatic ring.
- The substituents are numbered to give the lowest possible locants.
- Alphabetical order governs the naming sequence of substituents.
Therefore, the correct IUPAC name is: 5-sec-butyl-2-ethylphenol.