Give IUPAC name of the following compound:
$CH_3-CH_2-CH_2-CH(Br)-CH(CH_3)-CH_2-CHO$
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 4-Bromo-3-methylheptanal
To determine the IUPAC name, follow the systematic steps of nomenclature.
Step 1: Identify the principal functional group
The compound contains the –CHO group, which represents an aldehyde.
Aldehydes take priority in numbering and naming.
Thus, the parent suffix will be:
–al
Step 2: Identify the longest carbon chain containing –CHO
Counting from the aldehyde carbon:
CHO – CH₂ – CH(CH₃) – CH(Br) – CH₂ – CH₂ – CH₃
Total carbon atoms = 7
Therefore the parent chain is:
heptanal
Step 3: Number the chain
Numbering starts from the aldehyde carbon (C-1).
1 – CHO
2 – CH₂
3 – CH(CH₃)
4 – CH(Br)
5 – CH₂
6 – CH₂
7 – CH₃
Step 4: Identify substituents
Substituents present:
- Methyl group at C-3
- Bromo group at C-4
Step 5: Arrange substituents alphabetically
Substituents are written in alphabetical order:
Bromo before Methyl
Thus the name becomes:
4-Bromo-3-methylheptanal