See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the functional group: The structure contains a C=O bonded to a nitrogen atom, making it an amide. Step 2 - Identify the substituents on nitrogen: The nitrogen has two ethyl groups (-CH2CH3) attached. In the given answer, one is called 'ethyl' and one is called 'propyl' — wait, let us re-examine. The answer states N,3-diethyl-N-propylpentanamide, meaning nitrogen has one ethyl group and one propyl group. Looking at the structure again: the nitrogen bears two substituents that appear as ethyl groups (-CH2CH3), but the answer specifies one is propyl. One chain on N is -CH2CH3 (ethyl) and the other is -CH2CH2CH3 (propyl), which may be harder to distinguish visually but the given answer confirms N-ethyl and N-propyl substitution. Step 3 - Identify the parent chain for the acyl portion: The chain attached to the carbonyl goes: C=O - CH2 - CH(Et) - CH2 - CH3. Counting carbons in the longest chain through the carbonyl: C1(carbonyl)-C2(CH2)-C3(CH with ethyl branch)-C4(CH2)-C5(CH3) = pentanoic acid backbone → pentanamide. Step 4 - Identify the branch on the acyl chain: At C3 there is an ethyl group (-CH2CH3), giving the locant '3-ethyl'. Step 5 - Assemble the name: Parent chain = pentanamide; branch on chain = 3-ethyl; substituents on N = one ethyl (N-ethyl) and one propyl (N-propyl). Alphabetical order and locants: N,3-diethyl-N-propylpentanamide. The 'N,3-diethyl' groups the N-ethyl and 3-ethyl together under 'diethyl' with their respective locants, and N-propyl is listed separately. Step 6 - Confirm: The prefix 'N,3-diethyl' means there is an ethyl at N and an ethyl at C3; 'N-propyl' means a propyl group on N; 'pentanamide' is the five-carbon amide chain. This matches the drawn structure. Therefore, the correct answer is N,3-diethyl-N-propylpentanamide.