Question

Which of the following will not give a primary amine?

• A. $C{H_3}CN\xrightarrow{{LiAl{H_4}}}$
• B. $C{H_3}NC\xrightarrow{{LiAl{H_4}}}$
• C. $CH_{3}CONH_{2}\xrightarrow{LiAl{{H}_{4}}}$
• D. $CH_{3}CONH_{2}\xrightarrow{Br_{2},\,\,NaOH}$

Answer 1

Answer: (B)

$C{H_3}NC\xrightarrow{{LiAl{H_4}}}$

Answer 2

$CH _{3} NC +4 H \xrightarrow{ LiAlH _{4}} \underset{2^{\circ}\text{amine}}{CH _{3} NHCH _{3}}$
Isocyanides are reduced to $2^{\circ}$ amines.
$CH _{3} NC +4 H \xrightarrow{LiAlH_4} CH_3CH_4NH_2(1^{\circ}$ amine)
$CH _{3} CONH _{2} \xrightarrow{ LiAlH _{4}} CH _{3} CH _{2} NH _{2}$ ( $1^{\circ}$ amine)
$CH _{3} CONH _{3}+ Br_2 + 4KOH \to RNH_2$
Hofmann bromamide reaction
$+ K_2CO_3 + 2KBr + H_2O$