Question

In the IUPAC name of following compound, there is something wrong. Find the mistake.
N-Ethyl-6-oxo-5-propylheptanamide

• A. Principal functional group is incorrectly chosen
• B. Incorrect prefix for locant is used
• C. Parent chain is incorrectly selected
• D. Locants name is not written in order of priority recommended by IUPAC

Answer 1

The correct option is C Parent chain is incorrectly selected

Here, amide group has higher priority than keto group, therefore former is the principal functional group and later is a locant. The longest carbon chain starting from carbon of the amide group would be the parent chain. Hence, in face parent chain has eight carbon as:
Ketones ( >C=O )
Prefix : oxo/keto

Amides $(-CON{H}_2,-CONHR,-CON{R}_2)$
Suffix: amide/ carboxamide

Parent chain is of eight carbon hence root word is octane.

Correct IUPAC name would be
N-Ethyl-5-(1-oxoethyl)octanamide.