Texto Ininteligível

Prévia do material em texto

Chapter 15 Suggested solutions for Chapter 15 115 Suggested solution The compound is a simple cyclopentenal. The ¹³C NMR assignment is not all certain. G. Magnusson and S. Thorén, J. Org. Chem., 1973, 38, 1380. 1.83 (2H,t) H H 30.3 40.8 H LiBr 2.50 (2H, dt) 1.26 (6H, 25.9 43.6 H to 153.4 H CHO 6.78 (1H, t) 9.82 (1H, s) 152.7 189.2 Problem 11 Female boll weevils (a cotton pest) produce two isomeric compounds that aggregate the males for food and sex. A few mg of two isomeric active compounds, grandisol and Z-ochtodenol, were isolated from 4.5 million insects. Suggest structures for these compounds from the spectroscopic data below. Signals marked * exchange with D₂O. Z-Ochtodenol. m/z: 154 (C₁₀H₁₈O), 139, 136, 121, 107, 69 (100%). (cm⁻¹): 3350, 1660. (p.p.m.): 0.89 (6H, s), 1.351.70 (4H, broad m), 1.41 (1H, s*), 1.96 (2H, s), 2.06 (2H, t, Hz), 4.11 (2H, d, J 7 Hz), and 5.48 (1H, t, J Hz). Grandisol. m/z: 154 (C₁₀H₁₈O), 139, 136, 121, 109, 68 (100%). (cm⁻¹): 3630, 32503550, and 1642. (p.p.m.): 1.15 (3H, s), 1.42 (1H, dddd, J 1.2, 6.2, 9.4, 13.4 Hz), 1.351.45 (1H, m), 1.551.67 (2H, m), 1.65 (3H, s), 1.701.81 (2H, m), 1.911.99 (1H, m), 2.52* (1H, broad t, J 9.0 Hz), 3.63 (1H, ddd, J 5.6, 9.4, 10.2 Hz), 3.66 (1H, ddd, J6.2, 9.4, 10.2 Hz), 4.62 (1H, broad s), and 4.81 (1H, broad s). (p.p.m.): 19.1, 23.1, 28.3, 29.2, 36.8, 41.2, 52.4, 59.8, 109.6, and 145.1. Purpose of the problem Further practice at structure determination of natural products with all the data properly presented. Suggested solution The structures are shown below. J. M. Tumlinson et al., Science, 1969, 166, 1010, but see K. Mori et al., Liebig's Annalen, 1989, 969 DH for the spectra of ochtodenol and (Z)-ochtodenol grandisol K. Narasaka et al., Bull. Chem. Soc. Jap., 1991, 64, 1471 for the spectra of grandisol. H Problem 12 Suggest structures for the products of these reactions. 0 0 1. OTs 12B 2. base MeOH Data for compound 12A: C₁₀H₁₃OP, IR (cm⁻¹): 1610, 1235; δH (p.p.m.): 6.57.5 (5H, m), 6.42 (1H, t, J 17 Hz), 7.47 (1H, dd, J 17, 23 Hz), and 2.43 (6H, d, J 25 Hz). Data for compound 12B: C₁₂H₁₆O₂; IR: CH and fingerprint only; δH (p.p.m.): 7.25 (5H, s), 4.28 (1H, d, J4.8 Hz), 3.91 (1H, d, J 4.8 Hz), 2.96 (3H, s), 1.26 (3H, s), and 0.76 (3H,