In reaction (1), Gabriel phthalimide synthesis cannot be used to prepare aniline because aryl halides do not undergo nucleophilic substitution (SN2) with potassium phthalimide due to partial double bond character of the C-X bond.
In reaction (2), the reduction of isocyanide (R−NC) with Sn/HCl yields a secondary amine (R−NHCH3), not a primary amine (R−CH2NH2).
In reaction (3), propanamide reacts with Br2 and KOH (Hoffmann Bromamide Degradation) to give ethanamine. This is a correct reaction.
In reaction (4), the −NHCO− group is attached to two rings. The ring attached to the nitrogen atom is activated (ortho/para directing) due to the lone pair on N, while the ring attached to the carbonyl group is deactivated. Therefore, nitration should occur on the ring attached to the Nitrogen atom at the para position, not on the ring attached to the Carbonyl group.



