Question

The IUPAC name of the following compound is:

• A. 4-Hydroxyhept-1-en-6-yne
• B. 4-Hydroxyhept-6-en-1-yne
• C. Hept-6-en-1-yn-4-ol
• D. Hept-1-en-6-yn-4-ol

Hint:

When naming organic compounds, identify and number the substituents, functional groups, and multiple bonds to derive the correct IUPAC name.

Answer 1

The Correct Option is D

The problem asks for the IUPAC name of the given compound. To determine the correct name, we'll perform a step-by-step analysis based on IUPAC nomenclature rules:

1. The longest carbon chain contains 7 carbon atoms, hence the parent name is "heptane."
2. The compound contains both a double bond and a triple bond. According to IUPAC rules, the chain is numbered such that the multiple bond closest to the end receives the lowest possible number. Here, the numbering starts from the right to give the double bond position as 1 and the triple bond position as 6.
3. Numbering the chain this way: CH₂=CH-CH₂-CH(OH)-CH₂-C≡CH shows positions for double bond as 1 (en-) and triple bond as 6 (yn-).
4. The hydroxyl group (OH) is taken as a substituent, and its location on the chain is at carbon 4 (4-ol).

Thus, the correct IUPAC name of the compound is "Hept-1-en-6-yn-4-ol."

Explanation of other options:

• 4-Hydroxyhept-1-en-6-yne: Incorrect as it does not correctly prioritize numbering for the double and triple bonds.
• 4-Hydroxyhept-6-en-1-yne: Incorrect placement of the double bond and triple bond numbering.
• Hept-6-en-1-yn-4-ol: Incorrect prioritization of the triple bond position over the double bond.

Answer 2

To determine the IUPAC name of the given compound, we will follow standard nomenclature rules:

1. Identify the longest carbon chain containing both the double bond and the triple bond. In this compound, the longest chain consists of 7 carbon atoms.
2. Number the carbon chain such that the double bond gets the lowest possible number. In this case, numbering from the right gives the double bond a position of 1 and the triple bond a position of 6.
3. Identify and number any substituents attached to the main chain. Here, a hydroxyl (OH) group is attached to the 4th carbon.
4. Combine the components into the name, indicating the position of the functional groups and unsaturations: 
   The correct name is Hept-1-en-6-yn-4-ol.

Justification of options:

4-Hydroxyhept-1-en-6-yne

• - Incorrect: The hydroxyl group location is correct, but the numbering suggests a different structure.

4-Hydroxyhept-6-en-1-yne

• - Incorrect: This suggests numbering prioritizes the triple bond over the double bond.

Hept-6-en-1-yn-4-ol

• - Incorrect: The numbering places the double bond at a higher number, which is against IUPAC naming conventions.

Hept-1-en-6-yn-4-ol

• - Correct: This follows all IUPAC rules for correct numbering and substituent identification.