Question

What is the major product Y in the following reaction sequence?

• A.

  

• B.

  

• C.

  

• D.

  

Hint:

Carboxylic acid is a meta-directing group in electrophilic substitution; bromination with Br\(_2\)/FeBr\(_3\) adds Br at the meta position.

Answer 1

The Correct Option is A

Step 1: The given reaction involves **protection of an amide group** using benzene sulfonyl chloride in the presence of pyridine, forming a sulfonamide intermediate. Step 2: On hydrolysis, the intermediate converts back to the **corresponding acid**, benzoic acid. Step 3: The benzoic acid then undergoes **electrophilic aromatic substitution** with Br\(_2\)/FeBr\(_3\), and bromine substitutes the meta-position due to the electron-withdrawing effect of the carboxylic group. Step 4: Therefore, the final product Y is **3-bromobenzoic acid**.