Synthesis
(2E)-3-Cyclohexyl-2-propenoic acid was prepared from ethyl (E)-3-cyclohexyl-2-propenoate by a hydrolysis reaction. The procedure was as follows: ethyl (E)-3-cyclohexylpropenoate was hydrolyzed under standard conditions to give trans-3-cyclohexylacrylic acid in 78% yield. The product was colorless needle-like crystals with a melting point of 46-47 °C (hexane recrystallization). Analyzed by 1H NMR (CDCl3, 400 MHz), the chemical shifts δ: 1.09-1.38 (m, 5H, cyclohexyl-H), 1.63-1.85 (m, 5H, cyclohexyl-H), 2.18 (m, 1H, cyclohexyl-H), 5.78 (d, J = 16.0 Hz, 1H, =CH-CO2-), 7.01 (dd, J = 6.8 Hz, 16.0 Hz, 1H, cyclohexyl-CH=). 13C NMR (CDCl3, 100 MHz) analysis showed chemical shifts δ: 25.7 (t, cyclohexyl), 25.9 (t, cyclohexyl), 31.6 (t, cyclohexyl), 40.5 (d, cyclohexyl), 118.0 (d, =CH-CO2-), 157.1 (d, cyclohexyl-CH=), 171.3 (s, C=O). IR spectra (KBr) showed the characteristic absorption peak at 1686 cm-1. Mass spectrometry results: EI-MS m/z 154 (M+); FAB-MS m/z 154 (M+); HR FAB-MS m/z 154.0995 (M+, calculated value of C9H14O2 154.0994) . Elemental analysis results: calculated values for C9H14O2: C, 70.10; H, 9.15. measured values: C, 70.01; H, 9.18. All spectral data are in agreement with literature reports (Alhamadsheh et al., 2007).
References
[1] Journal of the American Chemical Society, 2007, vol. 129, # 7, p. 1910 - 1911
[2] Phytochemistry (Elsevier), 2012, vol. 84, p. 56 - 67,12
