Question

The main product of the reaction of $CH _{3} CONH _{2}$ with $Br _{2}$ in aqueous potassium hydroxide medium is

• A. $CH _{3}- CH _{2}- NH _{2}$
• B. $CH _{3} Br$
• C. $CH _{3} CONHBr$
• D. $CH _{3} NH _{2}$

Answer 1

Answer: (D)

This is Hoffmann's bromide reaction. In this reaction, product compound has one less '$C$' atom than reactant.
So it causes shortening of ' $C$ ' chain.
$-, CONH _{2} \rightarrow- NH _{2}$
$CH _{3} CONH _{2}+ Br _{2}+4 KOH \rightarrow CH _{3} NH _{2}+2 KBr +2 H _{2} O + K _{2} CO _{3}$