Structure of an anti-plasmin inhibitor, eckol, isolated from the brown alga Ecklonia kurome OKAMURA and inhibitory activities of its derivatives on plasma plasmin inhibitors.
摘要:
Eckol (1)是从褐藻 Ecklonia kurome OKAMURA 中分离出来的一种具有二苯并-1,4-二恶英骨架的新型绿单宁,是一种强效、特异性和专一性的抗浆细胞蛋白抑制剂。根据光谱数据,特别是通过负核奥弗豪泽尔效应(NOE)阐明了其结构,并通过 X 射线分析最终确定其为 1-(3,5-二羟基苯氧基)-2,4,7,9-四羟基二苯并-1,4-二恶英。通过与重氮甲烷的甲基化反应以及过甲酸埃克醇(1b)的选择性去甲基化反应,制备了一些埃克醇的部分甲氧基化衍生物,以确定其对血浆中主要的血浆蛋白酶抑制剂--α2-巨球蛋白和α2-血浆蛋白酶抑制剂的抑制活性的结构要求。
Regioselective Reactions of Highly Substituted Arynes
作者:Pamela M. Tadross、Christopher D. Gilmore、Pradeep Bugga、Scott C. Virgil、Brian M. Stoltz
DOI:10.1021/ol1000796
日期:2010.3.19
The fully regioselective reactivity of four new highly substituted silyl aryl triflate aryne precursors in aryne acyl-alkylation, acyl-alkylation/condensation, and heteroannulation reactions is reported. The application of these more complex arynes provides access to diverse natural product scaffolds and obviates late-stage functionalization of aromatic rings.
A transition-metal-free three-phase four-component couplingreaction (3P-4CR) involving KCl, arynes, chloroalkanes and CO2 has been reported for the first time, enabling the incorporation of both chloro and CO2 into an aryne simultaneously. The reactions for the synthesis of different types of o-chloro benzoates can be selectively modulated by the chloroalkane utilized. The corresponding products can
Synthesis of bicyclic ethers by a palladium-catalyzed oxidative cyclization-redox relay-π-allyl-Pd cyclization cascade reaction
作者:Michaelyn C. Lux、Melissa L. Boby、Joshua L. Brooks、Derek S. Tan
DOI:10.1039/c9cc03775f
日期:——
are of interest in probe and drug discovery. A palladium-catalyzedcascade reaction has been developed to provide efficient access to these scaffolds from readily available linear diene–diol substrates. A Pd redox-relay process is used strategically to transmit reactivity between an initial oxypalladative cyclization and a subsequent π-allyl-Pd cyclization at remote sites. The reaction affords a variety
Yb(OTf)<sub>3</sub>-Catalyzed Reactions of 5-Alkylidene Meldrum's Acids with Phenols: One-Pot Assembly of 3,4-Dihydrocoumarins, 4-Chromanones, Coumarins, and Chromones
作者:Eric Fillion、Aaron M. Dumas、Bryan A. Kuropatwa、Neil R. Malhotra、Tamsyn C. Sitler
DOI:10.1021/jo052000t
日期:2006.1.1
Yb(OTf)3-catalyzed annulation reactions of phenols with 5-alkylidene Meldrum's acids enabled the synthesis of structurally diverse heterocycles in high isolated yields. A series of 4-substituted 3,4-dihydrocoumarins, 2,2-disubstituted 4-chromanones, coumarins, and 2-substituted chromones were readily and efficiently assembled, including the naturallyoccurringcoumarins citropten, scoparone, and ayapin
Asymmetric Synthesis of 4-Aryl-3,4-dihydrocoumarins by <i>N</i>-Heterocyclic Carbene Catalyzed Annulation of Phenols with Enals
作者:Guo-Tai Li、Zhi-Ke Li、Qing Gu、Shu-Li You
DOI:10.1021/acs.orglett.7b00088
日期:2017.3.17
enantioselective synthesis of 4-aryl-3,4-dihydrocoumarins was realized through direct annulation of phenols with enalscatalyzed by dihydroisoquinoline-type NHC (DHIQ-NHC), an N-heterocycliccarbene derived from l-phenylalanine. The catalytic reaction proceeds with a wide scope of electron-rich phenols and enals providing structurally diverse 4-aryl-3,4-dihydrocoumarins in good to excellent yields