Hoffmann’s bromamide degradation reaction

As the name of the reaction suggests, Hoffmann’s bromamide degradation reaction was given by August Wilhelm Von Hoffmann. It is also known as the Hoffmann Rearrangement Reaction. This reaction is used to form primary amines. Let’s understand the name of the reaction first so that it will be easy for you to remember the reaction. 

Hoffmann – Named after the German Chemist August Wilhelm Von Hoffmann.

Bromamide – Bromine molecule and amide are used in the reaction. 

Degradation – One less Carbon atom you get in the product than reactant after the reaction. Thus, degradation of carbon takes place. 

In Hoffmann bromamide degradation reaction, an amide reacts with bromine and an aqueous solution of sodium hydroxide which produces primary amine. This is a degradation reaction as the primary amine in the product has one carbon lesser than primary amide (in the reactant). 

Hoffmann bromamide degradation reaction can be written as follows – 

R-CO-NH₂          +       Br₂      +       4NaOH                      →    R-NH₂  + Na₂CO₃  +  2NaBr + 2H₂O 

(General amide)     (Bromine)    (Sodium Hydroxide)    

In other words, Hoffmann reaction can be written as follows – 

Primary amide Br₂+NaOH→ Primary amine 

Secondary and tertiary amides don’t show Hoffmann bromamide reactions. Only one unit or molecule of bromine is used in the reaction.