Why is there a difference in the reactivity of these two compounds?

Acetanilide is more reactive than N-methylbenzamide in an electrophilic aromatic substitution reaction with chlorosulfonic acid even though both compounds have amide functional groups bonded to the aromatic ring.

1 Answer
Jan 2, 2018

Amide group in acetanilide is donating group to benzene, and the amide group in N-methylbenzamide is electron withdrawing group.

Explanation:

In acetanilide, the benzene bonded with the nitrogen atom (amide group) that make this substituent role as donating group. The lone pair electron from nitrogen atom was donated to benzene and increased the nucleophilicity of benzene. On the other hand, in N-methyl benzamide, benzene bonded to carbon atom (from amide group) that make it role as electron withdrawing. It can decrease the nucleophilicity of benzene in aromatic substitution reaction