Final answer:
To convert aniline into a less powerful activating group, perform a Friedel-Crafts acylation reaction with an acyl chloride or an acid anhydride. This converts the amino group into an amide, greatly reducing its activating effect and preventing multiple reactions from occurring on the aromatic ring.
Step-by-step explanation:
To convert aniline into a less powerful activating group, you can acylate the amino group. This is typically achieved by reacting aniline with an acyl chloride or an acid anhydride to introduce an acyl group (for instance, a benzoyl or acetyl group) onto the nitrogen atom of aniline, forming an amide. This is known as the Friedel-Crafts acylation reaction. The resulting amide is a much less powerful activating group due to the resonance stabilization of the lone pair of electrons on the nitrogen, which makes it less available for electron donation to the aromatic ring. This minimizes further reaction of the ring in electrophilic aromatic substitution reactions, thus avoiding multiple reactions occurring.