Delépine reaction

The Delépine reaction is a reaction names of organic chemistry and named after the French chemist Marcel Delépine. It refers to the synthesis of primary amines by acid hydrolysis of quaternary salts of hexamethylenetetramine, which are accessible from the reaction of hexamethylenetetramine with benzyl or alkyl halides.

Reaction mechanism

The mechanism is explained using an alkyl chloride. Also possible is the use of alkyl bromides. 1 reacted with the hexamethylenetetramine, benzyl or alkyl halide 2 to form a quaternary ammonium salt 3, always only one nitrogen atom is alkylated. By heating under reflux in concentrated ethanolic hydrochloric acid solution, this quaternary ammonium salt decomposes in several reaction steps to a hydrohalogenide 11 by-products of the reaction are formaldehyde, which reacts with the water present in the solution of ethanol of formaldehyde, and ammonium chloride. After a basic workup, the desired amine produced 12

Advantages of this reaction are the selective access to the primary amines ( no side reactions) from readily available starting materials and short reaction times with relatively simple reaction conditions. As an example the synthesis of 2 - of 2,3- dibromopropene Bromallylamin be mentioned.