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    Home > Biochemistry News > Biotechnology News > The Tang Yefeng team designed and synthesized a group of molecules from the Xanthanolide family.

    The Tang Yefeng team designed and synthesized a group of molecules from the Xanthanolide family.

    • Last Update: 2020-08-19
    • Source: Internet
    • Author: User
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    Xanthanolide is a class of poly-semiterinests isolated from the chrysanthemum herons.
    so far, there are hundreds of Xanthanolides that have been identified, most of which have 5/7 double-ringed skeletons.
    Depending on the C-8-bit stereochemistry, Xanthanolide can be further divided into two categories: the 5/7 trans structure and the 5/7 shun structure, xanitin (1) and 8-epi-xanitin (2) shown in Figure 1, respectively.
    1 and 2 are the two most important substances in the Xanthanolide family because they can be derived into other, more complex and novel structures.
    for example, 2 after a series of double-bond isomers, 6-to-electron ringing, and intermolecular DA reactions can be converted into the most complex monomer structure of Xanthipungolide (3).
    in addition to monomer Xanthanolide, there are a variety of dipolymers in nature, called Pungiolide.
    most Pungiolide can be synthesized by 2 biosynthetics.
    Figure 1. Xanthanolide monomers and dipolymers and their biosynthetic sources: In addition to structural diversity, Xanthanolide has a wide range of biological activities, such as anti-cancer, antiviral, antibacterial, antimalarial and anti-inflammatory, which provides valuable resources for the development of new drugs.
    there has been a lot of research on the chemical synthesis and structural-active relationship sonofhood of these compounds, however, only a few double-ringed Xanthanolides have been fully explored.
    other molecules with more complex structures, such as 3-10, have not yet been fully synthesized.
    Professor Yefeng Tang from Tsinghua University's School of Pharmacy has long been dedicated to the full synthesis of complex natural products, including multiple compounds from the Xanthanolide family.
    recently, the Tang Yefeng Task Force published an online paper on Ange.Chem.Int.Ed., reporting on the synthesis of a series of Xanthanolide members, including 2-10.
    authors also include Professor Lihong Hu of Nanjing University of Traditional Chinese Medicine and members of his team.
    can be seen from Figure 1 that compound 2 is the common precursor of target molecule 3-10, so the primary goal of the study is to develop a synthetic route of 2.
    although the full synthesis of 2 has been reported early, but the synthesis route is long, low efficiency, making it difficult to use.
    , the author tries to develop a simpler and more practical compound 2 synthesis method, reverse synthesis analysis shown in Figure 2.
    2 can be obtained by 13 of the polydecomposition and cross-re-decomposition of the elene-off ring, while 13 can be obtained by 14 functional ization, and 14 can be obtained by the acrylonitrile 15 and the hand beta-acetaldehyde 16 of the acrylonitrile and endolated series reaction.
    Figure 2.8-epi-xantin's inverse synthesis analysis Source: Angew.Chem.Int.Ed. The synthetic route of the (-8-epi-xantin(2) is shown in Figure 3.
    the author to acetate (17) as the starting material, through the three-step e-type isomer 15, through the addition of ethyl acetylene, acetylation and boronation, at the same time, the handaldehyde compound 16 by the catalyzed asymmetry 1,4-conjugate plus preparation. After
    obtained 15 and 16, the authors conditioned the key acrylonitrile boronation and endolated series reactions (Figure 4).
    results show that the yield of products 14 and 22 is relatively good (entry 10) under the action of the hand phosphoric acid (CPA) catalyst cat.E.
    next, 14 is deTIPS protection base and oxidation elimination, and the target compound 2 is obtained.
    so far, the author obtained (-8-epi-xanthanitin(2) with a maximum single-line step of 7 steps and a total yield of 15%.
    Figure 3. -8-epi-xanthanitin-selective synthesis Source: Ange.Chem.Int.Ed.Figure 4.Instagram/Intered-intered series reaction condition screening Source: Angew.Chem.Int.Ed.) After successfully realizing the amplifyable synthesis of -8-epi-xanthanthin(2), the author proceeds to synthesize 3-10.
    inspired by the early work, the author synthesized Xanthipungolide (3, Figure 5) with a total yield of 40% of the total yield, through the reaction of C2-C3 double-bond isomerization, 6-x electron cycling and single-line oxygen-excitation.
    in addition, the authors found in the study that 2 reactions at high temperatures (180 degrees C) in ethanol for 4.5 hours were obtained from the single product PungiolideD (8), while the reaction was 2 hours at 110 degrees C in toluene/ethanol (5:1), mainly Prepungiolide (12) and some raw materials (Figure 6).
    12 will have a differential isomerization in the process of silicone column tomography, converted to 24, and then heated it can also be converted to 8.
    Figure 5.xanthipungolide Bionic Full Synthesis Source: Ange.Chem.Int.Ed.A. Figure 6.PungiolideD Bionic Full Synthesis Source: Angew.Chem.Int.Ed. Finally, author obtained other Pungiolide through post-modification (Figure 7).
    8 under the action of Stryker reagent (Ph3P) CuH 6, C2,C3 double-bond edp, get PungiolideM (9);
    12 oxidized by DABCO and O2, and then added to Me2S, you can get Pungiolide A (4) and its C-11 differential isomers (25), as well as the dual-bond migration product Pungiolide E (5), with yields of 18%, 36% and 26%, respectively.
    and selective cyclic oxidation 4 and 5 can be obtained by Pungiolide B (6) and Pungiolide L (7) respectively.
    Figure 7. Pungiolide's collective synthesis source: Angew.Chem.Int.Ed. Summary: The Tang Yefeng team designed and synthesized a group of molecules from the Xanthanolide family. Highlights of the
    synthesis work are: (1) simple synthesis of ethyl boronandation and intraestation series reaction simply by CPA, -8-epi-xantin; (2) The first pungiogiode synthesis through a series of double-bondiasis, 6-ion electron cyclology and intermolecular DA reaction bionic synthesis Xanthipungolide; (3) the first diversification of Pungiode through head-to-tail-connected DA reactions.
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