Q10(d). Structure from mass, IR and NMR spectra: a bromo acid
Identify the structure of organic compound which exhibits the following spectral data: MS m/z (relative intensity): 194, 196 (M⁺, M⁺ + 2), 177, 179 (30), 115 (40), 97 (50), 60 (100). IR ν (cm⁻¹): 3500–2500, 2942, 1711, 1195. ¹H NMR (CDCl₃) δ: 10.6 (1H, D₂O exchangeable), 3.4 (t, 2H), 2.59 (t, 2H), 1.87–1.82 (m, 2H), 1.65 (pent., 2H), 1.55 (pent., 2H). ¹³C NMR (CDCl₃) δ: 179, 33.6, 33.4, 32.3, 27.5, 23.7.
Answer in brief
6-Bromohexanoic acid, Br–(CH₂)₅–COOH, C₆H₁₁BrO₂ (M = 194 and 196).
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Coversstructure elucidation6-bromohexanoic acidMcLafferty ion m/z 60M+2 bromine pattern13C NMRIR carboxylic acid
All parts of Question 10
- 10(a) Perkin reaction, then three steps to 2-methylindane10 marks
- 10(b) 4π ring opening, then 6π ring closure: the intermediate II5 marks
- 10(c) Cope rearrangement of cis-2,3-divinyloxirane5 marks
- 10(d) Structure from mass, IR and NMR spectra: a bromo acid10 marks