Question

Gabriel-Pthalimide synthesis is given priority in the synthesis of primary amines.

Hint:

The Gabriel-Pthalimide synthesis is a preferred method for preparing primary amines because it avoids the formation of secondary and tertiary amines, which are commonly encountered in other synthetic routes.

Answer 1

Gabriel-Pthalimide synthesis is preferred for synthesizing primary amines because it offers a selective and reliable method for their preparation. The key advantage of this method is that it exclusively yields primary amines, avoiding the formation of secondary and tertiary amines, which are often byproducts in other amination reactions. In the Gabriel-Pthalimide synthesis, phthalimide (an imide derivative) is reacted with an alkyl halide in the presence of a base (such as potassium hydroxide, \(KOH\)) to perform an nucleophilic substitution. This reaction results in the formation of an N-alkylphthalimide intermediate. The next step involves the hydrolysis of this intermediate to release the primary amine and regenerate phthalic acid (which is typically removed). The reaction proceeds as follows: \[ \text{Phthalimide} + \text{R-Cl} \xrightarrow{\text{KOH}} \text{N-alkylphthalimide} \] \[ \text{N-alkylphthalimide} \xrightarrow{\text{Hydrolysis}} \text{Primary amine} + \text{Phthalic acid} \] This method provides good yields of primary amines and is favored because it avoids the formation of unwanted amine byproducts. Additionally, Gabriel-Pthalimide synthesis is relatively simple and provides a high degree of purity for the primary amines produced.