What is the major product formed when p -toluidine undergoes the following sequence of reactions? (i) Ac ₂ O , pyridine (ii) Br ₂ , CH ₃ COOH (iii) H ₃ O ^+ (iv) NaNO ₂ , HCl , 273 K (v) CuCN

Step-by-step solution

The starting material, p -toluidine (4-methylaniline), is first treated with acetic anhydride ( Ac ₂ O ) in pyridine to protect the highly reactive - NH ₂ group, forming N -acetyl- p -toluidine. During bromination ( Br ₂ /CH ₃ COOH ), the - NHCOCH ₃ group is a stronger activating and directing group than the - CH ₃ group. Thus, the incoming electrophile ( Br ^+ ) is directed to the position ortho to the - NHCOCH ₃ group, yielding 2-bromo-4-methylacetanilide. Acid hydrolysis ( H ₃ O ^+ ) removes the acetyl protectin