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GATE 2022 CY – Question 12

Organic Chemistry · Heterocyclic Compounds: Nomenclature of mono- and bicyclic, as well as mono- and di-heteroatomic compounds, Structure, preparation, properties and reactions of furan, pyrrole, thiophene, pyridine, indole, quinoline and isoquinoline. · 1 mark · Multiple choice

The starting material Y in the following reaction is

Diagram for GATE 2022 CY question 12
  1. Diagram A
  2. Diagram B
  3. Diagram C
  4. Diagram D

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Correct answer: (B) Diagram B

Explanation

The reaction is the Bartoli indole synthesis: an ortho-substituted nitroarene reacts with excess vinyl Grignard reagent through reduction, addition and rearrangement/cyclization. Ortho-bromonitrobenzene therefore provides the observed bromoindole, **B**. Aniline and aryl azide do not follow this nitro-specific sequence.