UPSC Civil Services (Mains), Chemistry optional · 2025 · Paper II
Q3(c)(i). Missing reagents and intermediate
Question
Provide the structure of missing reagents and intermediates in the following synthesis: 3-methylbutan-1-ol → (M) → (N) → O → (P) 1-amino-4-methylpentan-2-ol. [scheme given in the paper]
Answer in brief
M = PCC, CH₂Cl₂; N = NaCN / H⁺ (HCN); O = 2-hydroxy-4-methylpentanenitrile; P = LiAlH₄, then H₂O.
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CoverscyanohydrinPCCLiAlH4 reduction of nitrileβ-amino alcoholHenry reaction
All parts of Question 3
- 3(a)(i) Products of two reactions10 marks
- 3(a)(ii) Ketone A from isobutanol alone5 marks
- 3(b)(i) Cyclopropane from tert-butyl chloroacetate and ethyl acrylate10 marks
- 3(b)(ii) Structures of C and D5 marks
- 3(c)(i) Missing reagents and intermediate10 marks
- 3(c)(ii) Photolysis of the α-diazoketone in methanol10 marks