137790-18-2Relevant academic research and scientific papers
Total Synthesis of the Antiviral Natural Product Houttuynoid B
Kerl, Thomas,Berger, Florian,Schmalz, Hans-Günther
supporting information, p. 2935 - 2938 (2016/03/25)
The first total synthesis of houttuynoid B, a powerful antiviral flavonoid glycoside from the Chinese plant Houttuynia cordata, is described. In a key step, a Baker-Venkataraman rearrangement employing an already glycosylated substrate was used to efficiently set up the fully functionalized carbon skeleton. The required benzofuran building block was prepared through a domino Sonogashira coupling/5-endo-dig cyclization and converted into a stable 1-hydroxybenzotriazole-derived active ester prior to linking with a galactosylated hydroxyacetophenone unit. The elaborated synthesis requires only nine steps (11 % overall yield) along the longest linear sequence and paves the way for the preparation of structurally related compounds for further biological evaluation.
Facile synthesis of norwogonin, isoscutellarein, and herbacetin
Yuan, Hu,Ye, Ji,Chen, Hao,Zhao, Zeng,Luo, Xukai,Zhang, Weidong,Sun, Qingyan
supporting information, p. 3389 - 3391 (2016/07/11)
An expeditious synthesis of norwogonin, isoscutellarein, and herbacetin, has been accomplished by a strategy featuring a borylation of sterically hindered aryl iodide and a one-pot oxidation to generate the C-3 and C-8 OH groups. The total synthesis gives excellent yields and conventional flash column chromatography is not needed for purification.
Lewis acid-triggered selective zincation of chromones, quinolones, and thiochromones: Application to the preparation of natural flavones and isoflavones
Klier, Lydia,Bresser, Tomke,Nigst, Tobias A.,Karaghiosoff, Konstantin,Knochel, Paul
, p. 13584 - 13587 (2012/10/08)
A Lewis acid-triggered zincation allows the regioselective metalation of various chromones and quinolones. In the absence of MgCl2, a C(3) zincation is observed, whereas in the presence of MgCl2 or a related Lewis acid, C(2) zincation occurs. Applications to a natural flavone, isoflavone, and quinolone are shown.
Synthesis, and cyclization to aurones and flavones, of alkoxy-substituted aryl, arylalkynyl ketones
Kerr, Penelope J.,Pyke, Simon M.,Ward, A. David
, p. 350 - 358 (2008/09/19)
Acylation of 1,3,5-tribenzyloxybenzene with alkoxy-substituted phenylpropioloyl chlorides provides the corresponding aryl alkoxylarylalkynyl ketones in which one of the benzyl groups has been removed. Cyclization of these phenolic ketones using basic reagents (potassium carbonate in acetone is best) provides the corresponding aurone system. When the phenolic group of the alkynyl ketones is protected as the t-butyldimethylsilyl ether followed by cyclization, using 18-crown-6 and potassium fluoride, mixtures of the corresponding aurones and flavones are produced. A by-product from the formation of the ketones is the corresponding β-chlorochalcone, which can also be cyclized to an aurone product using basic conditions. Similarly, the t-butyldimethylsilyl ethers of the HCl adducts can also be cyclized to a mixture of the corresponding aurones and flavones. CSIRO 2008.
Isotopic labelling of quercetin 3-glucoside
Caldwell, Stuart T.,Petersson, Hanna M.,Farrugia, Louis J.,Mullen, William,Crozier, Alan,Hartley, Richard C.
, p. 7257 - 7265 (2007/10/03)
The potentially important dietary antioxidant, quercetin 3-O-β-d-glucoside, has been 13C-labelled at C-2 of the flavonoid unit by synthesis in 15% yield over five steps from [13C]carbon dioxide. The route is appropriate for radiochemical synthesis. Formation of the protected 3-glucosylated flavonol appears to result from [1,7]-sigmatropic rearrangement with migration of a benzyl group followed by cyclisation. A free 5-OH results even when a phosphazene superbase is used.
