Here's what happens:
1. Formation of N-Bromo Benzamide: Bromine reacts with benzamide in the presence of NaOH to form N-bromo benzamide. The bromine atom is substituted onto the nitrogen of the amide group.
2. Base-promoted Rearrangement: The N-bromo benzamide is then treated with excess NaOH. This strong base promotes a rearrangement reaction where the bromine atom migrates from the nitrogen to the carbon adjacent to the carbonyl group. This step leads to the formation of an isocyanate intermediate.
3. Hydrolysis: The isocyanate intermediate is unstable and readily undergoes hydrolysis in the presence of water. This results in the formation of an amine and carbon dioxide.
Overall Reaction:
Benzamide + Br₂ + 4 NaOH → Aniline + Na₂CO₃ + 2 NaBr + 2 H₂O
Mechanism:
The mechanism of this reaction is complex and involves several steps. You can find a detailed explanation of the mechanism in many organic chemistry textbooks.
Key Points:
* Hofmann Degradation: This reaction is a versatile method for converting amides to primary amines with one less carbon atom.
* Reaction Conditions: The reaction is typically carried out in an alkaline medium (NaOH) and requires the presence of bromine.
* Product: The final product is an amine with one less carbon atom than the starting amide. In the case of benzamide, the product is aniline.
Let me know if you would like a more detailed breakdown of the mechanism or have any other questions!
