Question

1. Write structures of different isomeric amines corresponding to the molecular formula C₄H₁₁N.
2. Write the IUPAC names of all the isomers.
3. What type of isomerism is exhibited by different pairs of amines?

Answer 1

The structures and their IUPAC names of different isomeric amines corresponding to the molecular formula C₄H₁₁N are given below:

Primary amines:

(I) CH₃CH₂CH₂CH₂NH₂

IUPAC name: Butan-1-amine

(II) \[\begin{array}{cc}
\ce{CH3CH2 - CH - CH3}\\
\phantom{..}|\\
\phantom{.....}\ce{NH2}
\end{array}\]

IUPAC name: Butan-2-amine

(III) \[\begin{array}{cc}
\phantom{...}\ce{CH3}\\
|\\
\ce{CH3 - C - NH2}\\
|\\
\phantom{...}\ce{CH3}
\end{array}\]

IUPAC name: 2-Methylpropan-2-amine

(IV) \[\begin{array}{cc}
\ce{CH3}\phantom{......}\\
|\phantom{.........}\\
\ce{CH3 - CH - CH2 - NH2}
\end{array}\]

IUPAC name: 2-Methylpropan-1-amine

Secondary amines:

(V) CH₃CH₂–NH–CH₂CH₃

IUPAC name: N-Ethylethanamine

(VI) CH₃CH₂CH₂–NH–CH₃

IUPAC name: N-Methylpropanamin

(VII) \[\begin{array}{cc}
\ce{CH3}\phantom{.....}\\
|\phantom{........}\\
\ce{CH3 - CH - NH - CH3}
\end{array}\]

IUPAC name: N-Methylpropan-2-amine

Tertiary amine:

(VIII) \[\begin{array}{cc}
\ce{CH3}\phantom{.}\\
|\phantom{....}\\
\ce{CH3 - N - CH2CH3}
\end{array}\]

IUPAC name: N, N-Dimethylethanamine

Isomerism exhibited by different amines includes chain isomerism, position isomerism, and functional group isomerism.

• Chain isomers: (I) and (IV), (II) and (III)
• Position isomers: (I) and (II), (I) and (III), (II) and (IV), (VI) and (VII)
• Metamers: (V) and (VI), (V) and (VII)
• Functional isomers: All primary amines are functional isomers of secondary and tertiary amines and vice versa.