Gabriel's synthesis is used frequency for the preparation of which of the following?

Step-by-step solution

Gabriel's phthalimide synthesis is used to prepare pure primary ( 1° ) amines. Phthalimide is treated with KOH to form potassium phthalimide, which reacts with a primary alkyl halide via S_N2 , followed by hydrolysis (or hydrazinolysis) to release the primary amine. This method avoids over-alkylation (formation of 2° and 3° amines) that occurs when NH₃ reacts directly with alkyl halides.