Indian Forest Service (Mains), Chemistry optional · 2021 · Paper II
Q6(d). Fischer indole synthesis
Question
Describe an indole synthesis in which a [3,3]-sigmatropic rearrangement is a key step.
Answer in brief
The Fischer synthesis converts an arylhydrazone into an indole through enehydrazine formation, [3,3] rearrangement, cyclization and loss of ammonia.
Part of VKC Basic
Read the key points and the full model answer with VKC Basic
VKC Basic (₹999 for 6 months) opens every solved answer, the notes, the handbook and the daily answer archive. Every Mains test series includes it.
The full model answer
As written for the answer booklet: the diagram carries the working, the lines stay short. Read here only; it is not offered as a download.
The handwritten model answer pages open with the VKC plan.
CoversFischer indole synthesis[3,3]-sigmatropic rearrangementphenylhydrazoneenehydrazine2-methylindole
All parts of Question 6
- 6(a)(i) Malonic ester ring synthesis5 marks
- 6(a)(ii) Wittig olefination5 marks
- 6(b)(i) Tertiary protein structure5 marks
- 6(b)(ii) End-group content of polystyrene5 marks
- 6(c)(i) Cyclization of a beta-hydroxy phenethylamide5 marks
- 6(c)(ii) Terylene from p-xylene5 marks
- 6(d) Fischer indole synthesis5 marks
- 6(e) Acid equivalent of nylon-6,65 marks