(aromatic residue), 1696 cm–1 (C=O), 3425 (OH), 1635 (-C=C-H). 1H NMR (acetone-d6, δ, ppm, J/Hz): 0.89 (3H, t, J = 6.9,
terminal methyl), 1.27 (br.s, (CH2)n), 1.69 (2H, m, CH2-2″), 3.93 (3H, s, OMe-3′), 4.17 (2H, t, J = 6.7, CH2-1″), 4.82 (1H, br.s,
OH-3′ exchangeable with D2O), 6.23 (1H, d, J = 16, H-1), 6.86 (1H, d, J = 8.0, H-5′), 6.94 (1H, d, J = 2.0, H-2′), 7.13 (1H, dd,
+
J = 8.0 and 2.0, H-6′) and 7.58 (1H, d, J = 16, H-2). EI MS m/z (rel. int.): 390 [M] (100), 194 (85), 177 (65), 57 (55).
Hexacosanyl-3-hydroxy-4-methoxy-trans-cinnamate (Hexacosanylisoferulate) 2. Colorless flakes mp 79–81°C
22
+
(petroleum ether–benzene), [α]D 0°C (c 0.71). EI MS m/z (rel. int.): 502 C36H62O4 M (100), 194 (85), 177 (65), 57 (55).
UV (λmax, MeOH): 331, 296 and 238 nm. IR (νmax, KBr, cm–1): 1610, 1520 cm–1 (aromatic residue), 1695 cm–1 (C=O), 3350
(OH). 1H NMR (acetone-d6, δ, ppm, J/Hz): 0.88 (3H, t, J = 6.9, terminal methyl), 1.23 (br.s, (CH2)n), 1.68 (2H, m, CH2-2″),
3.89 (3H, s, OMe-4′), 4.15 (2H, t, J = 6.7, CH2-1″), 6.22 (1H, d, J = 16, H-1), 6.84 (1H, d, J = 8.2, H-5′), 6.86 (1H, d, J = 2.0,
H-2′), 7.13 (1H, dd, J = 8.2 and 2.0, H-6′), 7.59 (1H, d, J = 16, H-1) and 8.12 (1H, br.s, OH-3′ exchangeable with D2O). 13
C
NMR (acetone-d6, δ ppm): 14.0 (C-26″), 22.4–31.9 (C-2″ to C-25″), 55.9 (4′-OMe), 64.5 (C-1″), 109.7 (C-1), 115.0 (C-5′),
+
115.7 (C-2′), 123.2 (C-6′), 127.4 (C-1′), 144.8 (C-3′, C-4′, C-2), 169.1 (C=O). EI MS m/z (rel. int.): 502 [M] (100), 194 (85),
177 (65), 57 (55).
Acid Hydrolysis. 21 mg of 2 was refluxed with a solution of 0.2 M KOH in MeOH (12 mL) on a steam bath for 4 hrs
under N2. The reaction mixture was diluted with H2O (12 mL) and extracted with Et2O three times. The combined extracts were
dried over anhydrous Na2SO4 and evaporated to give 11 mg residue, which was subjected to prep. TLC using petroleum
ether–CH2Cl2 (8:2) as eluent to give hexacosanyl alcohol 4 (7 mg) as colorless plates, mp. 74–76°C. The compound was
identified from GC-MS analysis. The aqueous fraction was acidified with dil. H2SO4 and extracted with EtOAc three times.
The combined extracts were dried over anhydrous Na2SO4 and evaporated to give 9 mg residue, which was subjected to prep.
TLC using (CHCl3–MeOH, 9:1, Rf 0.28) as eluent to give isoferulic acid 3 (4 mg), which was identified by 1H NMR spectra
and comparison with authentic sample, mixed melting point, and co-TLC.
Synthesis of Hexacosanyl-3-hydroxy-4-methoxy-trans-cinnamate (Hexacosanylisoferulate) 2. 3-Hydroxy-4-
methoxy-trans-cinnamic acid (39 mg) and hexacosanyl alcohol (61 mg) were dissolved in dry benzene (50 mL) and one drop
of conc. H2SO4. A Dean Stark apparatus was used to remove the water formed during the reaction. The benzene was evaporated
under reduced pressure and the ester formed was purified on TLC using benzene–petroleum ether (9:1) to give 2, which was
elucidated.
ACKNOWLEDGMENT
Theauthor is verygrateful tothe International Foundation for Science (IFS) for partialfinancialsupport under research
grant No. F/3334-1 and to Dr. F. Ghia for identifying and collecting the plant material.
REFERENCES
1.
R. E. Schultes and R. F. Raffauf, The Healing Forest Medicinal and Toxic plants of Northwest Amazonia,
Dioscorides Press, Portland, Oregon, 1990, p. 229.
2.
3.
4.
5.
6.
H. Achenbach, M. Stocker, and M. A. Constenla, Z. Naturforsch., 41c, 164 (1986).
M. Mizuno, T. Tanaka, N. Matsuura, M. Iinuma, and C. Cheih, Phytochemistry, 29, 2738 (1989).
J. Wandji, A. E. Nkengfack, and Z. T. Fomum, J. Nat. Prod., 53, 1425 (1990).
K. Ezaki, M. Satake, T. Kusumi, and H. Kakisawa, Tetrahedron Lett., 32, 2793 (1991).
H. R. El-Seedi, Nat. Prod. Res., 19, 197 (2005).
7.
8.
H. R. El-Seedi, P. A. G. M. De Smet, O. Beck, G. Possnert, and J. G. Bruhn, J. Ethnopharmacol., 101, 238 (2005).
B. Das and A. Kashinatham, Indian J. Chem., 36B, 1077 (1997).
9.
I. A. Pearl and D. L. Beyer, J. Org. Chem., 216 (1951).
10.
11.
12.
13.
14.
Z. T. Fomum, J. F. Ayafor, J. Wandji, W. G. Fomban, and A. E. Nkengfack, Phytochemistry, 25, 757 (1986).
A. M. Balde, M. Claeys, L. A. Pieters, V. Wray, and A. J. Vlietinck, Phytochemistry, 30, 1024 (1991).
P. Malgaard and H. Ravn, Phytochemistry, 27, 2411 (1988).
S. Gibbons, K. T. Mathew, and A. I. Gray, Phytochemistry, 51, 465 (1999).
Z. Jiron, Approaching Optimal Conditions for Running Liquid Adsorption Column Chromatography Using Simple
Computational Models. Licentiate Thesis, Department of Chemistry, Organic Chemistry, Royal Institute of
Technology: Stockholm, 1996.
258