Question

What is the IUPAC name of following compound?

• A. 3-Chloro-4-methyl-5-bromohept-1-ene
• B. 4-Methyl-3-bromo-5-chlorohept-6-ene
• C. 3-Bromo-4-methyl-5-chlorohept-6-ene
• D. 5-Bromo-3-chloro-4-methylhept-1-ene

Hint:

Rule priority: Double bond gets lowest number → then substituents arranged alphabetically

Answer 1

The Correct Option is A

Step 1: Identify longest chain
The longest chain contains 7 carbon atoms → parent = heptene

Step 2: Numbering of chain
Number from the end nearest to the double bond to give it lowest locant: \[ \text{Double bond at position 1} \Rightarrow \text{hept-1-ene} \]

Step 3: Identify substituents
From structure:
• Cl at carbon 3
• Methyl at carbon 4
• Br at carbon 5

Step 4: Arrange substituents alphabetically
Order: Bromo, Chloro, Methyl \[ \Rightarrow 5\text{-bromo},\; 3\text{-chloro},\; 4\text{-methyl} \]

Step 5: Write full name
\[ 3\text{-Chloro-4-methyl-5-bromohept-1-ene} \] Conclusion:
This matches option (A). Final Answer: Option (A)