See image — Aldehydes Ketones and Carboxylic Acids Chemistry Question

💡 Solution & Explanation

Concept: The Gabriel synthesis is a method for preparing primary amines from alkyl halides using potassium phthalimide. Step 1: Identify reagent (1). The reagent shown is potassium phthalimide (NK salt of phthalimide, with the O above and the cyclic imide structure implied by the notation). DMF is the polar aprotic solvent used to facilitate the SN2 reaction. Step 2: Reaction of benzyl bromide with potassium phthalimide in DMF. Benzyl bromide (Ph-CH2-Br) undergoes SN2 substitution with potassium phthalimide. The nitrogen of phthalimide (a good nucleophile) displaces bromide, forming N-benzylphthalimide: the phthalimide nitrogen is now bonded to CH2Ph. Step 3: Hydrolysis with HO-/H2O (basic hydrolysis). The phthalimide ring is cleaved by hydroxide, releasing the primary amine Ph-CH2-NH2 and phthalate (or phthalic acid under acidic workup, but the amine is liberated). This is the classic Gabriel synthesis. Step 4: Product (A) is benzylamine: Ph-CH2-NH2. Why other options fail: (a) Ph-NH2 (aniline) would require direct substitution on the ring nitrogen without the CH2 group - incorrect, the CH2 is retained. (c) Ph-CH2-NH-CO2H would imply a carbamic acid product, not consistent with Gabriel synthesis hydrolysis. (d) Ph-CH2-NH-CHO would be a formamide, not the product of this reaction sequence. Therefore, the correct answer is B.