Which one of the following on reduction with lithium aluminium hydride yields a secondary amine?
- Methyl isocyanide
- Acetamide
- Methyl cyanide
- Nitroethane
Answer
(1) Methyl isocyanide
Solution
Isocyanides are reduced by LiAlH4 to secondary amines containing a methyl group on nitrogen:
CH3-N C LiAlH4 CH3-NH-CH3 (secondary amine)
⇒ As per NCERT, acetamide gives ethanamine, CH3CONH2 LiAlH4 CH3CH2NH2; methyl cyanide gives ethanamine, CH3CN LiAlH4 CH3CH2NH2; nitroethane gives ethanamine, CH3CH2NO2 CH3CH2NH2 – all primary amines.
∴ Methyl isocyanide yields the secondary amine (N-methylmethanamine).
Answer: (1)