Explain why there is only one product for this reaction, although at first glance their could be two. Why does reaction only occur with the NH2 and not on the ring?
Reacuviuy or Anilines Recall that the -NR2 group is strongly electron donating .-NR2 is such a good donating group that protonation and and is an ortho, para director oxidation are problematic under electrophilic aromatic substitution conditions . The amino nitrogen must be protected with an electron- withdrawing group (C-O!) Nucleophilic acyl substitution ArNHCCH, Nucleophilic CH Arylamine N-Acetylarylamine Electrophilic aromatic substitution of N-acetylarylamines proceeds without issue Example: Nitration of Anilines
Solution
Amine with its lone pair of electrons is more electron donating and ortho para director. But when it is acylated the lone pair is more involved with the carbonyl group by resonance. Hence, the reactivity of the amine is no longer there for futher acylation..
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