How would the bromination of acetanilide catalyzed by an acid begin?

I'm aware of how the mechanism works with a catalyst like FeBr3 but, not with an acid. What would the acid protonate to begin the reaction?

Question

How would the bromination of acetanilide catalyzed by an acid begin?

I'm aware of how the mechanism works with a catalyst like FeBr3 but, not with an acid. What would the acid protonate to begin the reaction?

kainui · Answer

Try pushing electrons around. You have some on the oxygen and nitrogen to play with in acetanilide. 

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There's to start you off. Now remember, water is a good leaving group, and you will end up with two bromines attached.