What is the correct IUPAC name for the following compound?
A)2,4-dimethyl-2-pentenone
B)2,5-dimethylcyclopenten-3-one
C)2,4-dimethylcyclopent-2-enone
D)3,5-dimethylcyclopent-2-enone
E)2-methyl-5-methylcyclopent-2-enone

Question

What is the correct IUPAC name for the following compound? 
A)2,4-dimethyl-2-pentenone 
B)2,5-dimethylcyclopenten-3-one 
C)2,4-dimethylcyclopent-2-enone 
D)3,5-dimethylcyclopent-2-enone 
E)2-methyl-5-methylcyclopent-2-enone

Quizplus · Accepted Answer

Starting from the longest chain, we have a five-membered ring containing a ketone functional group (cyclopentenone). The ring is substituted with two methyl groups at positions 2 and 4, hence the name 2,4-dimethylcyclopent-2-enone. Option A is incorrect because it contains an extra carbon atom in the chain. Option B is incorrect because the ring has a double bond between carbons 2 and 3, whereas it should have a double bond between carbons 2 and 4. Option D is incorrect because the ring has a double bond between carbons 2 and 4, whereas it should have a double bond between carbons 2 and 3. Option E is incorrect because it implies a double bond between carbons 4 and 5, which is not present in the molecule.

What Is the Correct IUPAC Name for the Following Compound