Question

Give reasons of the following:

Acetylation of aniline reduces its activation effect.

Answer 1

Acetylation of aniline gives acetanilide, which undergoes nitration at low temperature, yielding the para-nitro product in high yield. The modifying acetyl group can then be removed by acid-catalyzed hydrolysis, to yield para-nitroaniline.

Although the activating influence of the amino group has been reduced by this procedure, the acetyl derivative remains an ortho/para-directing and activating substituent.