Amines - Result Question 29
####31. Which one of the following on reduction with lithium aluminium hydride yields a secondary amine?
[2007]
(a) Methyl isocyanide
(b) Acetamide
(c) Methyl cyanide
(d) Nitroethane.
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Solution:
- (a) Reduction of alkyl isocyanides in presence of $LiAlH_4$ yields secondary amines containing methyl as one of the alkyl group.
$ \begin{aligned} & R-N \triangleq C+4[H] \xrightarrow{LiAlH_4} R-NH-CH_3 \\ & 2^{\circ} \text{ amine } \\ & \text{ e.g., } CH_3-N \nRightarrow C+4[H] \xrightarrow{LiAlH_4} \\ & CH_3-NH-CH_3 \\ & \text{ dimethyl amine } \end{aligned} $
whereas, alkyl cyanides give $1^{\circ}$ amine on reduction.
