The reactivity and stability of intermediates in the Gabriel synthesis vary significantly between amines and phthalimides.

In the Gabriel synthesis, either an amine or a phthalimide serves as a nucleophile that attacks a diethyl malonate molecule. This interaction forms an intermediate, which is subsequently hydrolyzed to yield the desired primary amine.

Amines are typically more reactive than phthalimides, primarily due to their greater basicity and minimal steric hindrance. This increased reactivity enables amines to form stable intermediates with diethyl malonate, which can then be easily hydrolyzed to generate the target amine.

Conversely, phthalimides exhibit reduced reactivity and often necessitate more vigorous reaction conditions to form stable intermediates. This reduced reactivity can be attributed to the phthalimide group’s presence, which introduces steric hindrance and diminishes the basicity of the nitrogen atom.

Despite these differences in reactivity, both amines and phthalimides can be utilized in the Gabriel synthesis to produce primary amines. However, amines are generally favored due to their higher reactivity and straightforward handling in the synthesis process.