68509-46-6Relevant academic research and scientific papers
The epimerization of sesamin and asarinin
Li, Chia-Ying,Chow, Tahsin J.,Wu, Tian-Shung
, p. 1622 - 1624 (2005)
Sesamin (1) and asarinin (2) are two C-7′ epimeric lignans. Molecular modeling by semiempirical methods indicated that 1 is more stable than 2 by about 2.5 kcal/mol. However, epimerization under acidic conditions led to a 44.8/55.2 equilibrium ratio of 1 and 2. Single-crystal X-ray diffraction analyses indicated that 1 was monoclinic with a = 10.0435(19) A, b = 6.9151(8) A, c = 11.8460(13) A, and 2 was triclinic with a= 5.595(5) A, b = 9.5910(18) A, c = 15.620(4) A. The unexpected equilibrium ratio of 1 and 2 indicated that structural changes are dependent on the conditions of the extraction processes.
Synthesis of Lignans Based on a Borate-mediated One-pot Sequential Suzuki-Miyaura Coupling of Cyclic Boranes
Sato, Ko,Tanaka, Hiroshi
supporting information, p. 9422 - 9428 (2021/05/26)
Lignans are a group of polyphenolic phytochemicals that possess a large spectrum of chemical structures and biological activities. Here the syntheses of lignans – anwulignan, burseran, dehydroxycubebin, ruburisandrin B, and sesamin – are achieved based on a borate-mediated one-pot sequential Suzuki-Miyaura coupling of cis- and trans-fused bicyclic boranes, which were prepared by diastereoselective cyclic hydroboration of exo-cyclic diene with cyclopentyl- and thexylboranes, respectively. A one-pot sequential Suzuki-Miyaura coupling of each cyclic borate with various aryl bromides initiated by activation of the cyclic borane with the carbon nucleophile provided 2,3-dibenzylbutane derivatives with different aromatic substituents. Finally, the syntheses of naturally occurring lignans were accomplished in several steps from the products of Suzuki-Miyaura coupling.
Enantioselective total synthesis of furofuran lignans via Pd-catalyzed asymmetric allylic cycloadditon of vinylethylene carbonates with 2-nitroacrylates
Zhao, Can,Khan, Ijaz,Zhang, Yong Jian
, p. 12431 - 12434 (2020/10/30)
Herein, a practical and efficient approach to tetrahydrofurans with three-stereocenters has been developed through Pd-catalyzed asymmetric allylic cycloaddition of vinylethylene carbonates (VECs) with 2-nitroacrylates under mild conditions. By using this asymmetric catalytic reaction as a key step, several furofuran lignans with stereodivergency have been effectively synthesized through 5- or 6-step sequences from readily available starting materials.
Chromatography-free “two-pots” asymmetric total synthesis of (+)-sesamin and (+)-aschantin
Hajra, Saumen,Garai, Sujay,Sen, Biswajit
, (2020/09/02)
A gram-scale chromatography-free asymmetric total synthesis of both homo- and heterobiaryl furofuran lignans containing at least one methylenedioxy phenyl unit such as (+)-sesamin and (+)-aschantin is accomplished in “two-pots” from easily accessible enantiopure lactone involving four steps in high overall yields. Steps- and pot economy are the key advantages of the protocol. Additionally, the bromo-functionality of the intermediates is useful for late stage functionalization.
Electochemical asymmetric dimerization of cinnamic acid derivatives and application to the enantioselective syntheses of furofuran lignans
Mori, Naoki,Furuta, Akiko,Watanabe, Hidenori
, p. 8393 - 8399 (2016/12/06)
A new electrochemical method for the asymmetric oxidative dimerization of cinnamic acid derivatives has been developed. This method enabled the enantioselective syntheses of furofuran lignans, yangambin, sesamin and eudesmin.
Metal Triflates for the Production of Aromatics from Lignin
Deuss, Peter J.,Lahive, Ciaran W.,Lancefield, Christopher S.,Westwood, Nicholas J.,Kamer, Paul C. J.,Barta, Katalin,de Vries, Johannes G.
, p. 2974 - 2981 (2016/11/02)
The depolymerization of lignin into valuable aromatic chemicals is one of the key goals towards establishing economically viable biorefineries. In this contribution we present a simple approach for converting lignin to aromatic monomers in high yields under mild reaction conditions. The methodology relies on the use of catalytic amounts of easy-to-handle metal triflates (M(OTf)x). Initially, we evaluated the reactivity of a broad range of metal triflates using simple lignin model compounds. More advanced lignin model compounds were also used to study the reactivity of different lignin linkages. The product aromatic monomers were either phenolic C2-acetals obtained by stabilization of the aldehyde cleavage products by reaction with ethylene glycol or methyl aromatics obtained by catalytic decarbonylation. Notably, when the method was ultimately tested on lignin, especially Fe(OTf)3 proved very effective and the phenolic C2-acetal products were obtained in an excellent, 19.3±3.2 wt % yield.
Stereocontrolled total syntheses of optically active furofuran lignans
Inai, Makoto,Ishikawa, Ryo,Yoshida, Naoto,Shirakawa, Nana,Akao, Yusuke,Kawabe, Yusuke,Asakawa, Tomohiro,Egi, Masahiro,Hamashima, Yoshitaka,Kan, Toshiyuki
, p. 3513 - 3521 (2015/11/17)
Plant products (+)-sesamin, (+)-sesaminol, (+)-methylpiperitol, (+)-aschantin, and (+)-5'-hydroxymethylpiperitol were synthesized in a highly stereocontrolled manner through l-proline-catalyzed bifunctional-urea-accelerated cross-aldol reaction, followed by biomimetic construction of the furofuran lignan skeleton through a quinomethide intermediate.
Total syntheses of (+)-sesamin and (+)-sesaminol
Ishikawa, Ryo,Yoshida, Naoto,Akao, Yusuke,Kawabe, Yusuke,Inai, Makoto,Asakawa, Tomohiro,Hamashima, Yoshitaka,Kan, Toshiyuki
, p. 1572 - 1574 (2015/02/19)
Total syntheses of (+)-sesamin (1a ) and (+)-sesaminol (1b), which are major components of sesame lignans derived from Sesamum indicum, were accomplished in a highly stereo-controlled manner. Key steps include an L-proline-catalyzed cross-a ldol reaction, which was accelerated with the aid of bifunctional urea 7, and the construction of a furofuran lignan skeleton through a quinomethide intermediate.
Stereospecific synthesis of endo-endo-3,7-dioxabicyclo[3.3.0]octane lignans using 1,6-bis(dipropylboryl)-2,4-hexadiene
Anfimov,Erdyakov,Gurskii,Bubnov
, p. 2336 - 2342 (2012/11/07)
A general methodology for the stereoselective synthesis of compounds of the 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane series was developed. The strategy includes allylboration of aromatic aldehydes with 1,6-bis(dialkylboryl)-2,4- hexadiene, ozonolysis of the thus obtained 1,4-diaryl-2,3-divinyl-1,4-diols, and subsequent intramolecular cyclization. This methodology was used for obtaining the naturally occurring lignans of the furofuran series, viz., diaeudesmin, diayangambin, epiasarinin, epieudesmin, epiyangambin, and asarinin.
METHOD AND APPARATUS FOR PRODUCING EPISESAMIN-RICH COMPOSITION
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Page/Page column 10; 11; 12-13, (2008/12/06)
To provide a process and an apparatus by means of which a composition that contains episesamin in a concentration greater than 50 wt% on the basis of the sum weight of sesamin and episesamin can be produced conveniently and at high yield. There are provided a process and an apparatus which comprise the step of applying epimerization to sesamin or a sesamin-containing composition so that at least part of the sesamin is converted to episesamin and the step of selectively crystallizing episesamin by recrystallization and by means of which a composition that contains episesamin in a concentration greater than 50 wt% can be produced conveniently and at high yield.
