Question

The IUPAC name of the following compound is CCOC1=CC=CCCC1 (A) 1-Ethoxy cyclohexa-1,3-diene (B) 1-Ethoxy cyclohexa-1,5-diene (C) 2-Ethoxy cyclohexa-1,5-diene (D) 2-Ethoxy cyclohexa-1,3-diene

Short answer

The IUPAC name of the given compound is (D) 2-Ethoxy cyclohexa-1,3-diene.

Step-by-step solution

Identify the parent chain

The parent chain for this compound is the cyclohexa-1,3-diene ring. The molecule has 6 carbon atoms in a ring and contains two double bonds at positions 1 and 3, which also dictates the numbering.

Identify the substituents and their positions

There is an ethoxy group (an ether derived from the ethyl group) attached to the parent chain. Notice where the ethoxy group is placed: either on carbon-1 or carbon-2.

Examine the options

Option (A) 1-Ethoxy cyclohexa-1,3-diene: This option has the ethoxy group attached to carbon-1. Double bonds are also in positions 1 and 3. Option (B) 1-Ethoxy cyclohexa-1,5-diene: This option has the ethoxy group attached to carbon-1. Double bonds are in positions 1 and 5, which is incorrect. Option (C) 2-Ethoxy cyclohexa-1,5-diene: This option has the ethoxy group attached to carbon-2. Double bonds are in positions 1 and 5, which is incorrect. Option (D) 2-Ethoxy cyclohexa-1,3-diene: This option has the ethoxy group attached to carbon-2. Double bonds are also in positions 1 and 3.

Determining the correct IUPAC name

Based on the given structure, the ethoxy group is attached to carbon-2, and the double bonds are at positions 1 and 3. Therefore, the correct IUPAC name is: 2-Ethoxy cyclohexa-1,3-diene. So, the answer is (D) 2-Ethoxy cyclohexa-1,3-diene.