Hoffmann Bromamide Degradation :
Amides with no substituent on the nitrogen when treated with a solution of `Br_2` or `Cl_2` in `KOH` yield only primary amines having one carbon atom less than the amides.
The reaction mechanism involves base - promoted `N`- bromination yielding `N`- bromo amide as an intermediate. The `N`- bromo amide then reacts with hydroxide ion to produce `N`- bromamide anion, which rearranges with the migration of `R` group and loss of `Br^-` ion to produce isocyanate. Base catalysed hydrolysis of isocyanate formed in the reaction mixture produces carbamate ion, which undergoes spontaneous decarboxylation resulting in the formation of amine.
The reaction mechanism involves base - promoted `N`- bromination yielding `N`- bromo amide as an intermediate. The `N`- bromo amide then reacts with hydroxide ion to produce `N`- bromamide anion, which rearranges with the migration of `R` group and loss of `Br^-` ion to produce isocyanate. Base catalysed hydrolysis of isocyanate formed in the reaction mixture produces carbamate ion, which undergoes spontaneous decarboxylation resulting in the formation of amine.