Reaction of Seretonin with aqueous Bromine

I have a question that I am stuck with. Serotonin (figure below) reacts with $\ce{Br2 (aq)}$ to give a compound. The marking scheme I am following says that Bromine only reacts in the ortho position of the phenol group. But I think it should also react with the double bond. Shouldn't the bromine react with the double bonded carbon?


Additionally when I react serotonin with $\ce{CH3COCl}$, shouldn't phenol and both the $\ce{NH}$ react? My marking scheme says it won't react with the double substituted $\ce{NH}$ group but does with the $\ce{NH2}$ group? Who is wrong here?


[![enter image description here](https://i.stack.imgur.com/tEg5y.jpg)](https://i.stack.imgur.com/tEg5y.jpg)




Talking about your double substituted -NH


The p orbital of nitrogen containing the lone pair overlaps with π bond of C=C, resulting in two pairs of electrons delocalized (spread) over these two centres (N & C), making the lone pair on N less available for donation to acylium ion (acyl chloride with chloride ion removed). Similarly, the electron density of C=C is also decreased which means it no longer shows addition reaction with Br2 (aq).


The delocalization of electrons is responsible for the unusual stability of some compounds and their reluctancy to react, as in the case of benzene ring.


While solving chemistry questions keep in mind the basic chemistry & try to solve things with reason and logic first.


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You may want to render the structure in this manner:


[![enter image description here](https://i.stack.imgur.com/Vt8a0.jpg)](https://i.stack.imgur.com/Vt8a0.jpg)


With this rendering, not only is the six-atom ring conjugated with six pi electrons, but so is the five-membered ring including the apparently nonbonded electron pair on the nitrogen atom. Thus the five-membered ring is also aromatic, specifically derived from [pyrrole](https://en.wikipedia.org/wiki/Pyrrole).


So the proposed double bond and nitrogen nonbonding pair in the five-membered ring do not effectively exist; they are delocalized/smeared into an aromatic ring. Accordingly the bromine and acetyl chloride do not have these functioms to react with and thus exclusively react elsewhere (bromine with the activated benzenoid ring, acetyl chloride with the unhindered amino group on the side chain).


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