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JEE Advanced levelSingle correct optionDifficulty 3 of 3nc140

4-Nitrotoluene is to be converted into 3-bromotoluene. Which sequence is correct?

  1. A / ; ; / dil. , 273-278 K;
  2. B; water; / dil. , 273-278 K;
  3. C; / dil. , 273-278 K; /
  4. D; / pyridine; in acetic acid; , heat; / dil. , 273-278 K;

Answer: D

Reduction gives 4-methylaniline, whose NHCOCH3 derivative (acetamido group, stronger director than CH3) is brominated ortho to nitrogen. After hydrolysis and deamination the Br is meta to CH3, giving 3-bromotoluene. Direct bromination of 4-nitrotoluene puts Br ortho to CH3 and ends as 2-bromotoluene, Br2 water gives dibromination, and CuBr gives 4-bromotoluene.
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