JEE Main · 2023 · 06 Apr 2023 · Shift 2 · Compounds Containing Nitrogen

The Gabriel phthalimide synthesis works by an ${\mathrm{S}}_{\mathrm{N}}2$ displacement on an alkyl or benzylic halide and therefore gives only primary amines in which nitrogen sits on an $s{p}^3$ carbon; it cannot make an amine bonded directly to the aromatic ring, because aryl halides do not undergo this substitution. For ${\mathrm{C}}_8{\mathrm{H}}_{11}\mathrm{N}$ the four degrees of unsaturation are taken up by the benzene ring, so the amines that can be prepared are those with $-\mathrm{N}{\mathrm{H}}_2$ on a side chain: 2-phenylethan-1-amine, 1-phenylethan-1-amine, and the ortho, meta and para isomers of methylbenzylamine. The number of such aromatic primary amines is 5.