The reaction in which an amide is treated with bromine in presence of ethanolic solution of sodium hydroxide is called

Hoffmann bromamide degradation reaction

The correct answer is Option (4) → Hoffmann bromamide degradation reaction.

The Hoffmann bromamide degradation reaction involves the conversion of an amide into a primary amine by treating it with bromine (\(Br_2\)) in the presence of an ethanolic solution of sodium hydroxide (\(NaOH\)). In this reaction, the carbonyl group of the amide is lost, and the amine product formed has one less carbon atom than the original amide. Let us consider the example of Acetamide to describe the reaction:

In this reaction, acetamide is treated with bromine and alkali (like NaOH or KOH). The reaction results in the removal of the carbonyl group from the amide, converting it into a primary amine (in this case, methylamine). This is a very efficient method for converting amides to amines with one fewer carbon atom.

Mechanism:

Other Options:

Carbylamine test: Used to detect primary amines by reacting with chloroform and potassium hydroxide, forming an isocyanide (foul-smelling compound).

Hinsberg's test: Used to distinguish between primary, secondary, and tertiary amines by reacting them with benzene sulfonyl chloride.

Coupling reaction: Typically refers to reactions where two organic compounds are joined together, often involving aromatic diazonium salts and phenols or amines to form azo compounds.

Thus, the correct reaction described is the Hoffmann bromamide degradation reaction.