Answer: Acyl azide rearranges to isocyanate, which hydrolyses to primary amine.
- A Acyl azide rearranges to isocyanate, which hydrolyses to primary amine
- B It reduces an amide directly to the corresponding primary amine using LiAlH<sub>4</sub>
- C It is mechanistically identical to the Hofmann bromamide degradation
- D It proceeds using Br<sub>2</sub> and NaOH on the parent amide
Correct answer: A. Acyl azide rearranges to isocyanate, which hydrolyses to primary amine
Explanation: Curtius rearrangement: RCON<sub>3</sub> (acyl azide) → R-N=C=O (isocyanate) → RNH<sub>2</sub> upon hydrolysis.
In aniline, the nitrogen's lone pair is pulled into the benzene ring through resonance, leaving less electron density available to accept a proton - which is why aniline is a much weaker base than methylamine, where the lone pair is fully available.
Concept context
Nitrogen-containing organic compounds. Covers classification (primary, secondary, tertiary), basicity comparison, preparation methods, and reactions including diazotization and coupling, key for understanding dyes and pharmaceuticals.