Indian Forest Service (Mains), Chemistry optional · 2022 · Paper II
Q3(a)(ii). Amination through 3,4-pyridyne
Question
Complete the reaction of 3-chloropyridine with KNH₂/liquid NH₃ and give the mechanism.
Answer in brief
3-Aminopyridine and 4-aminopyridine form, approximately 1:2 in the classic experiment, through a 3,4-pyridyne intermediate.
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Covers3,4-pyridyneelimination–additionhetaryne3-chloropyridine aminationaminopyridines
All parts of Question 3
- 3(a)(i) Amination of 2-chloropyridine5 marks
- 3(a)(ii) Amination through 3,4-pyridyne10 marks
- 3(b) Steric control of Diels–Alder reactivity5 marks
- 3(c) Cinnamaldoxime rearrangement and ring closure10 marks
- 3(d) Aromatic character of diazines5 marks
- 3(e) Stability of three carbanions5 marks