13c Nmr Spectral Analysis Of Lignans From Araucaria Angustifolia

Pinoresinol dimethyl ether, secoisolariciresinol, lariciresinol, isolariciresinol and isolariciresinol-4′-methyl ether were isolated from the knots of dead trees of Araucaria angustifolia. The 13C NMR spectra of these compounds, their methyl and acetyl derivatives, and the corresponding one of matairesinol, have been recorded and the signals assigned. On the basis of these assignments, the structure of the new monomethyl ether of isolariciresinol has been established. © 1978.173499502IEEE Technical Committee on Distributed Processing (TCDP)de, Ferreira, (1975) Phytochemistry, 14, p. 2299Weinges, Spänig, (1967) Oxidative Coupling of Phenols, , The nomenclature and the numbering used in this paper are the ones reported by, W.I. Taylor, A.R. Battersby, Marcel Dekker, New YorkKlyne, Buckingham, (1974) Atlas of Stereochemistry, Absolute Configurations of Organic Molecules, p. 185. , Chapman & Hall, LondonPelter, Ward, Venkata, Sastry, (1976) Tetrahedron, 32, p. 2873Anjaneyulu, Madhusudhana, Kameswara, Ramachandra, Pelter, Ward, (1977) Tetrahedron, 33, p. 133Wenkert, Gottlieb, Gottlieb, Pereira, Formiga, (1976) Phytochemistry, 15, p. 1574. , and references cited thereinKelley, Harruff, Carmack, (1976) J. Org. Chem., 41, p. 449Castelão, Jr., Gottlieb, de, Mesquita, Gottlieb, Wenkert, (1977) Phytochemistry, 16, p. 735Imamura, Marsaioli, Barata, Ruveda, (1977) Phytochemistry, 16, p. 1842Stothers, (1972) Carbon-13 NMR Spectroscopy, , Academic Press, New YorkLevy, Nelson, (1972) Carbon-13 Nuclear Magnetic Resonance for Organic Chemists, , Wiley-Interscience, New YorkBuchanan, Stothers, Wu, 13C Nuclear magnetic resonance studies. XII. Conformational effects on13C shieldings in alicyclic oxygenated compounds (1969) Canadian Journal of Chemistry, 47, p. 3113The deshielding effects observed on C-9′ and C-9 by acetylation, although small (C-9′, Δδ = 66.4-66.2 = 0.2 ppm, C-9, Δδ = 63.4-6.26 = 0.8 ppm) are in agreement with the reported values for trans-4-t-butylcyclohexylmethanol acetate and trans-4-t-butylcyclohexylmethanol (carbinyl carbon Δδ = 69.3-68.9 = 0.4 ppm) [9]We thank Professor H. Erdtman (Royal Institute of Technology, Stockholm) and Professor R. C. Cambie (University of Auckland) for generous gift of lariciresinol and matairesinol respectivelyPelter, Ward, Gray, The carbon-13 nuclear magnetic resonance spectra of flavonoids and related compounds (1976) Journal of the Chemical Society, Perkin Transactions 1, p. 2475Acetylation of 6c to 6d, the same as 6e to 6f, shields C-4′ (Δδ = 6.2 ppm) and C-4 (Δδ = 0.7 ppm), but this effect is lower in the latter. Differences in shielding effects on acetylation were also observed in the transformation of 4a to 4b, (Δδ for C-4 = 5.2 ppm, Δδ for C-4′ = 3.7 ppm)Shapiro, (1977) Tetrahedron, 33, p. 1091Carbon-1′ of p-benzylphenol suffers a shielding effect (Δδ = 0.7 ppm) on acetylationThe PMR spectrum of 6f is in agreement with the proposed structure since it shows a clear doublet at δ 7 (J = 8 Hz), produced by the deshielding effect of acetylation on the ortho positions, in comparison with the corresponding ones of 6eErdtman, Tsuno, The Chemistry of the Order Cupressales. 56. Heartwood Constituents of Fitzroya cupressoides (Monlina) Johnston. (1969) Acta Chemica Scandinavica, 23, p. 2021Popoff, Theander, (1977) Acta Chem. Scand., 31 B, p. 32