Question

The rearrangement of acyl azide to isocyanate which yield an amine on heating is

• A. Curtius type
• B. Schmidt type
• C. Baeyer -Villiger type
• D. Both (a) and (b)

Answer 1

The correct option is A Curtius type

In Curtius rearrangement, acyl halides will react with sodium azide to give primary amines.

Mechanism of Curtius rearrangement:
1. Azide ion will attack the acyl carbon and replace the $Cl$ atom to acyl azide.
2. On heating the acyl azide, $N_2$ gets eliminated and the alkyl group gets migrated to form a isocyanate intermediate.
3. Isocyanate on hydrolysis gives primary amine and $C{O}_2$.

In schmidt rearrangement, only protonated azide is formed.

In Baeyer-Villeger peroxy acid derivative gets rearranged to form ester compound.

Hence, option (a) is correct.