Q6(j). 4-Bromobenzoyl chloride to 4-bromoaniline: Lossen rearrangement
Identify the product (R) and give a plausible mechanism. [scheme given in the paper: 4-bromobenzoyl chloride with a hydroxylamine-derived reagent, NEt₃, H₂O]
Answer in brief
R = 4-bromoaniline, BrC₆H₄NH₂, formed in one pot by a Lossen rearrangement through 4-bromophenyl isocyanate.
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CoversLossen rearrangementisocyanatehydroxamic acid4-bromoaniline1,2-aryl shift
All parts of Question 6
- 6(a) Cyclohexanone: self-condensation with NaOH, none with LDA4 marks
- 6(b) Ethyl acetoacetate with cyclohexanone: Knoevenagel condensation4 marks
- 6(c) Birch reduction of benzoic acid4 marks
- 6(d) HCl with 1-methyl-1-vinylcyclobutane: ring expansion4 marks
- 6(e) Cyclopentadiene with maleic anhydride: endo and exo adducts4 marks
- 6(f) UV absorption of aniline in neutral and in acidic solution4 marks
- 6(g) Aromatic proton shifts: NO₂, COOH and CF₃ as para substituents4 marks
- 6(h) Citral and citronellal by IR: conjugated and isolated C=O4 marks
- 6(i) 3-Methyl- and 4-methylpentan-2-one by mass spectrometry4 marks
- 6(j) 4-Bromobenzoyl chloride to 4-bromoaniline: Lossen rearrangement4 marks