Question

Identify tertiary amide.
(A) $C{{H}_{3}}CO-N(C{{H}_{3}})C{{H}_{2}}C{{H}_{3}}$
(B) $C{{H}_{3}}CON{{H}_{2}}$
(C) $C{{H}_{3}}CO-NHC{{H}_{3}}$
(D) None of these.

Answer 1

Hint: On the basis of the number of alkyl/aryl groups attached to the remaining two bonds of the nitrogen atom in the amide group determines the type of amide as a simple or substituted amide.

Complete step by step solution:
In the general formula of amide, it has a nitrogen atom linked to the carbonyl carbon. These can further be subdivided on the basis of the number of carbons atoms or alkyl/ aryl groups attached to the nitrogen atom as follows:
- When only two hydrogen atoms are attached to the nitrogen group. It is called the simple amide or the primary amide.
- When one of the hydrogen bonds is replaced by the alkyl/ aryl group attached to the nitrogen atom, it forms the secondary amide.
- When both the bonds of nitrogen are formed with the alkyl/ aryl group, it forms the tertiary amide.
So, both the secondary and tertiary amides are known as a substituted amide.
Thus, in the given molecules $C{{H}_{3}}CON{{H}_{2}}$ having only hydrogens attached to the amide group is a primary amide. In $C{{H}_{3}}CO-NHC{{H}_{3}}$ molecule, with only one bond formed with the methyl group and the other with hydrogen is a secondary amide. And in $C{{H}_{3}}CO-N(C{{H}_{3}})C{{H}_{2}}C{{H}_{3}}$ having two methyl groups attached to the amide group is a tertiary amide.

Therefore, the tertiary amide is option (A)- $C{{H}_{3}}CO-N(C{{H}_{3}})C{{H}_{2}}C{{H}_{3}}$.

Note: The general formula of primary amide will be $RCO-N{{H}_{2}}$ , for the secondary amide it will be $RCO-NHR$ and for the tertiary amide it will be $RCO-N{{R}_{2}}$, where R can be a same or different alkyl or aryl groups.