Q6(g). Two isomeric esters C₇H₁₄O₂ from ¹H NMR
¹H NMR spectrum of two isomeric esters P and Q with molecular formula C₇H₁₄O₂ are given below. Identify the structures of P and Q. Compound P: ¹H NMR (CDCl₃, δ): 3.78–3.8 (d, 1H), 2.52–2.7 (q, 2H), 1.7–1.9 (sept, 1H), 2.2–2.4 (t, 3H), 0.72–0.9 (d, 2H). Compound Q: ¹H NMR (CDCl₃, δ): 2.3–2.6 (q, 2H), 1.45 (s, 9H), 1.1–1.3 (t, 3H).
Answer in brief
P = 2-methylpropyl (isobutyl) propanoate, CH₃CH₂COOCH₂CH(CH₃)₂. Q = tert-butyl propanoate, CH₃CH₂COOC(CH₃)₃.
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Covers1H NMRester structureisobutyl propanoatetert-butyl propanoatespin-spin splitting
All parts of Question 6
- 6(a) Chlorocarbene from CH₂Cl₂; ring expansion of 3-methylindole4 marks
- 6(b) Ozonolysis of camphene, then Wolff–Kishner reduction4 marks
- 6(c) Reductive amination, then intramolecular aza-Michael addition4 marks
- 6(d) Benzaldehyde and ethane-1,2-dithiol: a 1,3-dithiolane4 marks
- 6(e) Amidomercuration–demercuration of hex-1-ene in acetonitrile4 marks
- 6(f) Dimerisation of cyclopentadiene: endo rule by frontier orbitals4 marks
- 6(g) Two isomeric esters C₇H₁₄O₂ from ¹H NMR4 marks
- 6(h) Mass spectrum of 3-butyn-2-ol: the ion of m/z 554 marks
- 6(i) Acetone: solvent shift of the n → π* band4 marks
- 6(j) Butyrophenone: McLafferty rearrangement and α-cleavage4 marks