Lignin–feruloyl ester cross-links in grasses. Part 2. Model compound syntheses
作者:John Ralph、Richard F. Helm、Stéphane Quideau
DOI:10.1039/p19920002971
日期:——
single geometrical isomer was produced. Synthesis of both isomers of derived compounds and detailed NMR analysis indicated that this was the expected Z-isomer. A model for β-5 coupled products, 3-[3-carboxy-2-(4-hydroxy-3-methoxyphenyl)-7-methoxy-2,3-dihydrobenzofuran-5-yl]acrylic acid bis(methyl 5-deoxy-α-L-arabinofuranosid-5-yl) ester, was obtained as a cis/trans mixture in 55% yield by radical coupling
Velde, Vincent Vande; Lavie, David; Gottlieb, Hugo E., Journal of the Chemical Society. Perkin transactions I, 1984, # 6, p. 1159 - 1164
作者:Velde, Vincent Vande、Lavie, David、Gottlieb, Hugo E.、Perold, Guido W.、Scheinmann, Feodor
DOI:——
日期:——
Synthesis of 4,8-bis(4-hydroxy-3-methoxyphenyl )-3,7-dioxabicyclo[3.3.0]octan-2-ones and determination of their relative configuration via long-range proton couplings
作者:St�phane Quideau、John Ralph
DOI:10.1039/p19930000653
日期:——
A short synthesis of the furofuranoid lignan, 4-cis,8-cis-bis(4-hydroxy-3-methoxyphenyl)-3,7-dioxabicyclo[3.3.0]octan-2-one (MEL), was accomplished via a simple regioselective hydride reduction of the dilactone parent [4-cis,8-cis-bis(4-hydroxy-3-methoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane-2,6-dione], followed by deoxygenation of the lactone-lactol intermediate via silane hydride transfer. The 4-trans-8-cis(iso-MEL) and the 4-cis-8-trans(epi-MEL) isomers, and a fourth related compound, featuring a 3-fused 5-membered ring skeleton were additionally formed. All four compounds were fully characterized by use of 1D and 2D NMR techniques. Examination of the long-range coupled proton network by delayed COSY experiments allowed determination of the relative configuration of these 4,8-diaryl-3,7-dioxabicyclo[3.3.0]octan-2-one structures. The pathways followed by these long-range proton couplings and implications of the long-range and vicinal couplings with respect to favoured conformations are discussed.
Stevens, David R.; Till, Clive P.; Whiting, Donald A., Journal of the Chemical Society. Perkin transactions I, 1992, # 2, p. 185 - 190
作者:Stevens, David R.、Till, Clive P.、Whiting, Donald A.