Concept:The
−OH group is the principal functional group, so it must receive the lowest possible locant while choosing the longest chain that also contains the double bond.
Explanation:The compound has an alcohol group and a double bond.
The longest carbon chain containing both has 9 carbons, so the parent chain is nonane.
Because it contains a double bond and an alcohol, the parent name ends in "en-ol".
Number the chain from the right so that the
−OH group gets position 4.
Numbering from the left would give the
−OH group position 6, which is not allowed.
With right-side numbering, the double bond is at position 5.
Two methyl substituents are present at positions 3 and 7.
Therefore, the IUPAC name is 3,7-dimethylnon-5-en-4-ol.
Answer:3,7-dimethylnon-5-en-4-ol (Option C)
