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An organic compound ($C_3H_9N$) (A), when treated with nitrous acid, gave an alcohol and $N_2$ gas was evolved. (A) on warming with $CHCl_3$ and caustic potash gave (C) which on reduction gave isopropylmethylamine. Predict the structure of (A).
A
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B
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C
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D
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Detailed Solution
A gives an alcohol and $N_2$ with nitrous acid, so A is a primary aliphatic amine: $C_3H_7NH_2 \xrightarrow{HONO} C_3H_7OH + N_2$
A primary amine warmed with $CHCl_3$ and KOH gives an isocyanide (carbylamine reaction): $C_3H_7NH_2 \xrightarrow{CHCl_3/KOH} C_3H_7-N\overset{\rightarrow}{=}C$ (C)
Reduction of an isocyanide gives a secondary amine with an N-methyl group: $C_3H_7-NC \xrightarrow{reduction} C_3H_7-NH-CH_3$
The product is isopropylmethylamine, $(CH_3)_2CH-NH-CH_3$, so the $C_3H_7$ group is isopropyl.
A is isopropylamine, $(CH_3)_2CH-NH_2$.