JEE MainChemistryAmines
Consider the following intermediate species formed during the Hoffmann bromamide degradation of an amide to a primary amine: (I) Alkyl isocyanate (II) N-Bromoamide (III) Carbamic acid (IV) N-Bromoamide anion The correct chronological sequence of their formation is:
Options
- A(II), (I), (IV), (III)
- B(IV), (II), (I), (III)
- C(II), (IV), (I), (III)
- D(II), (IV), (III), (I)
Correct answer
C. (II), (IV), (I), (III)
Step-by-step solution
The Hoffmann bromamide degradation of an amide ( RCONH ₂ ) to a primary amine ( RNH ₂ ) proceeds through the following sequence of intermediates: 1. The amide reacts with bromine to form N-bromoamide ( RCONHBr ), which is species (II). 2. The acidic proton on the nitrogen of the N-bromoamide is abstracted by the base ( OH ^- ) to form the N-bromoamide anion ( RCON ^- Br ), which is species (IV). 3. The N-bromoamide anion undergoes rearrangement (migration of the alkyl group with simultaneous loss of bromide ion) to