# Will ipso substitution work in both cases of vanillic and isovanillic acids here or not?

What will be the product of the 2 reactions when bromine is taken in excess?

I think ipso substitution will work here and there will be two $$\ce{Br}$$ substituting in both products, but in the book it was given that there will be three $$\ce{Br}$$ in the second one. I cannot understand why.

• Posting question as image or image link is highly discouraged for multiple reasons. Also, if a question is asked on Chemistry SE site, then, in contrary to sites like Quora, it is expected the author elaborates the topic in the question by at least basic own topic review and writes what he/she understands and what is the eventual stumble stone. The "quick questions" without explicitly expressed particular effort are not very welcome, and may be closed. – Poutnik May 31 '20 at 15:32
• – Yusuf Hasan May 31 '20 at 15:44
• @Poutnik: I have addressed that issue for now. But, OP should be aware of that for future perspectives. – Mathew Mahindaratne May 31 '20 at 17:09
• Neither acid gives ipso bromination. Chem. Abst. has ring bromination of vanillic acid but no record of the same process with isovanillic acid, which I find hard to believe. – user55119 Jun 1 '20 at 1:50