Hofmann rearrangement, also known as the Hofmann degradation, is an organic reaction that involves the conversion of primary amides to primary amines with the loss of one carbon atom. The reaction is named after its discoverer, August Wilhelm von Hofmann. The mechanism of Hofmann rearrangement involves several steps, including halogenation, rearrangement, and hydrolysis.Here is a step-by-step description of the mechanism for the Hofmann rearrangement:1. Halogenation: The reaction begins with the treatment of the primary amide with halogen chlorine or bromine and a strong base, typically sodium or potassium hydroxide. The halogen reacts with the amide, forming an N-haloamide intermediate. This step involves the electrophilic attack of the halogen on the amide nitrogen, followed by the deprotonation of the N-haloamide by the base.2. Formation of isocyanate intermediate: The N-haloamide undergoes rearrangement through a cyclic transition state, leading to the formation of an isocyanate intermediate. This step involves the migration of the R group alkyl or aryl from the carbonyl carbon to the nitrogen atom, with the simultaneous loss of a halide ion.3. Hydrolysis: The isocyanate intermediate reacts with water, undergoing hydrolysis to form a primary amine and carbon dioxide. The nitrogen atom of the isocyanate attacks a water molecule, followed by the protonation and loss of carbon dioxide to generate the primary amine.In summary, the Hofmann rearrangement is a reaction that converts primary amides to primary amines with the loss of one carbon atom. The mechanism involves halogenation, rearrangement, and hydrolysis steps, leading to the formation of an N-haloamide, an isocyanate intermediate, and finally, the primary amine product.