Análise Espectroscópica de Produtos

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Chapter 11 Suggested solutions for Chapter 11 79 chemical shifts of the alkene protons would be very different: predicted to be about 4.5 p.p.m. and Hb about δH 6.2 p.p.m. MeO H MeO 0 Hb 0 H D. H. Williams and I. Fleming, Spectroscopic methods in organic chemistry (5th edn), McGraw Hill, The third structure (which is the correct one) fits all the data. The two alkene protons are at London (1995). normal shifts for such protons (estimated from tables in Williams and Fleming: 6.35 p.p.m. for 5.53 p.p.m. for the two OMe groups on the ring are slightly different, and the loss of a More details of the discovery, biological activity, and structural methyl group in the mass spectrum is easily explained by removal of an electron from oxygen elucidation of precocene are given followed by loss of Me* to form a stable aromatic cation. by W.S. Bowers et al. Science, 1976, 193, 542. 6.42 or 6.58; 1H, S H 6.37; 1H, d. 10 Hz MeO Hb 5.54; 1H, d, J 10 Hz MeO 3.80 and 3.82 two 3H singlets MeO 0 MeO 0 MeO 0 1.34; 6H, $ 6.42 or 6.58; 1H, Problem 13 Suggest structures for the products of these reactions, interpreting the spectroscopic data. Though these products, unlike those in Problem 11, are reasonably logical, you will not meet the mechanisms for the reactions until Chapters 22, 29, and 23, respectively, and you are advised to solve the structures through the spectra. Br A, C-H and fingerprint only 153, 141, 127, 115, 59, 33, 24 MeO 1.21 (6H, d, Hz), 2.83 (1H, septuplet, Hz) 3.72 (3H, 6.74 (2H, d, J9 Hz), and 7.18 (2H, d, J9 Hz) B, 1745, 1730 OSIMe₃ + TICL4 202, 176, 62, 48, 34, 22, 15 1.21 (6H,s), 1.8 (2H, Hz), 2.24 (2H, t, Hz), 4.3 (3H, 10.01 s) CHO NaH 1730 OH + 164, 132, 130, 115, 64, 41, 29 F 2.32 (6H, 3.05 16 4.20 (2H, Hz), 6.97 (2H, d, J7 Hz), (2H, d, Hz), 9.97 (1H, Purpose of the problem Your second attempt at determining the structures of reaction products, now of moderate complexity.