- Bioinspired Photoredox Benzylation of Quinones
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3-Benzylmenadiones were obtained in good yield by using a blue-light-induced photoredox process in the presence of Fe(III), oxygen, and γ-terpinene acting as a hydrogen-atom transfer agent. This methodology is compatible with a wide variety of diversely substituted 1,4-naphthoquinones as well as various cheap, readily available benzyl bromides with excellent functional group tolerance. The benzylation mechanism was investigated and supports a three-step radical cascade with the key involvement of the photogenerated superoxide anion radical.
- Donzel, Maxime,Elhabiri, Mourad,Davioud-Charvet, Elisabeth
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p. 10055 - 10066
(2021/07/31)
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- Iron-catalyzed regioselective alkylation of 1,4-quinones and coumarins with functionalized alkyl bromides
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A simple and efficient Fe-catalyzed regioselective alkylation of 1,4-quinones and coumarins, using functionalized alkyl bromides as alkylating reagents, has been developed. The reaction proceeds under mild conditions with the addition of alkyl bromides to a wide range of 1,4-quinone and coumarin derivatives with a broad substrate scope and wide functional group tolerance to provide the products in good yields. Further application of these strategies could be extended to important biologically active antimalarial lead drugs, such as plasmodione on a gram scale in a single step for medicinal purposes.
- Li, Dengke,Shen, Xianfu
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supporting information
p. 750 - 754
(2020/02/11)
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- Bismuth-catalyzed methylation and alkylation of quinone derivatives with tert-butyl peroxybenzoate as an oxidant
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A bismuth-catalyzed methylation of quinones in the presence of tert-butyl peroxybenzoate (TBPB) was developed via a radical reaction mechanism. Particularly, TBPB was used not only as an efficient oxidant, but also as a green methyl source in such transformation. Moreover, this method could also be efficiently extended to the alkylation of quinones. This reaction tolerated a series of functional groups and prepared a series of derivatives of vitamin K3 and benzoquinone. Notably, antimalarial parvaquone was synthesized by the reaction.
- Yang, Jian,Dong, Yu,He, Shuai,Shi, Zhi-Chuan,Wang, Yu,Wang, Ji-Yu
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- Metal-free oxidative cross-dehydrogenative coupling of quinones with benzylic C(sp3)-H bonds
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A metal-free cross-dehydrogenative coupling of quinones with toluene derivatives has been established. A series of quinones were subjected to reaction with toluene derivatives in the presence of di-tertbutyl peroxide (DTBP) for direct synthesis of benzylq
- Dong, Yu,Yang, Jian,He, Shuai,Shi, Zhi-Chuan,Wang, Yu,Zhang, Xiao-Mei,Wang, Ji-Yu
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p. 27588 - 27592
(2019/09/12)
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- Radical Benzylation of Quinones via C-H Abstraction
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Herein we report the development of radical benzylation reactions of quinones using Selectfluor and catalytic Ag(I) initiators. The reaction is believed to proceed via a C-H abstraction mechanism after Ag(I)-mediated reduction of Selectfluor. This reaction occurs under mild conditions and is effective for a variety of quinones and radical precursors bearing primary benzylic carbons. The use of preformed Ag(4-OMePy)2NO3 as a catalyst proved effective in improving the reaction efficiency by reducing unwanted degradation pathways available to Selectfluor.
- Galloway, Jordan D.,Mai, Duy N.,Baxter, Ryan D.
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p. 12131 - 12137
(2019/10/02)
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- Metal-, Photocatalyst-, and Light-Free, Late-Stage C-H Alkylation of Heteroarenes and 1,4-Quinones Using Carboxylic Acids
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Contrary to the accepted convention, this work shows that Minisci-type C-H alkylation does not require any metal, photocatalyst, light, or prefunctionalization of the readily available and inexpensive carboxylic acids to proceed well under mild conditions. These mild conditions can be utilized for late-stage alkylations of complex molecules, including pharmaceutical compounds and light-sensitive compounds which degrade under photocatalytic conditions.
- Sutherland, Daniel R.,Veguillas, Marcos,Oates, Conor L.,Lee, Ai-Lan
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supporting information
p. 6863 - 6867
(2018/11/21)
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- Redox Polypharmacology as an Emerging Strategy to Combat Malarial Parasites
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3-Benzylmenadiones are potent antimalarial agents that are thought to act through their 3-benzoylmenadione metabolites as redox cyclers of two essential targets: the NADPH-dependent glutathione reductases (GRs) of Plasmodium-parasitized erythrocytes and m
- Sidorov, Pavel,Desta, Israel,Chessé, Matthieu,Horvath, Dragos,Marcou, Gilles,Varnek, Alexandre,Davioud-Charvet, Elisabeth,Elhabiri, Mourad
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supporting information
p. 1339 - 1351
(2016/07/22)
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- Copper-catalyzed regioselective cross-dehydrogenative coupling of coumarins with benzylic Csp3-H bonds
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A new copper-catalyzed regioselective cross-dehydrogenative coupling of coumarins with benzylic Csp3-H bonds has been developed. This reaction provides direct access to a wide range of 3-benzylcoumarins in moderate to good yields. The protocol was also extended successfully to other heterocyclic compounds, such as quinolinones.
- Zhou, Shi-Liu,Guo, Li-Na,Duan, Xin-Hua
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p. 8094 - 8100
(2015/02/02)
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- 1,4-NAPHTHOQUINONE DERIVATIVES AND THERAPEUTIC USE THEREOF
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Derivatives of formula (I) wherein A is selected from the following rings: and their preparation and their application as antimalarial agents.
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Page/Page column 33-34
(2009/10/22)
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- Synthesis and cytotoxicity of 9-substituted benzo[de]chromene-7,8-dione and 5-benzyl-9-substituted benzo[de]chromene-7,8-dione
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New Mansonone analogues of 9-substitued benzo[de]chromene-7,8-dione 5b-e and 5-benzyl-9-substitued benzo[de]chromene-7,8-dione 6a-e were prepared through a modified route. The first step involved a bulky base t-butylamine mediated regioselective deacetylation of 2-substituted-1,4-naphth-diyl diacetate, resulting in obtaining of monoacetate 4-acetate 2 in high yield. The mechanism of cyclization, debenzylation, and oxidation for the formation of 5a-e and 6a-e were discussed. The cytotoxicity of the prepared compounds 5 and 6 were comparable with naturally occurring Mansonone F. Copyright Taylor & Francis Group, LLC.
- Huang, Shi-Liang,Luo, Yi,Huang, Zhi-Shu,Wang, Xing-Yuan,Bu, Xian-Zhang,Liu, Pei-Qing,Ma, Lin,Xie, Bing-Fen,Liu, Zong-Chao,Li, Yue-Ming,Chan, Albert S. C.,Gu, Lian-Quan
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p. 2667 - 2684
(2007/10/03)
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- A new synthetic route to substituted quinones by radical-mediated coupling of organotellurium compounds with quinones
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Carbon-centered radicals generated from the corresponding organotellurium compounds react with a variety of quinones under photo-thermal conditions to give the monoaddition product in moderate to excellent yield. The reaction can be used for the synthesis of polyprenyl quinoid natural products and C-glycosides.
- Yamago, Shigeru,Hashidume, Masahiro,Yoshida, Jun-Ichi
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p. 6805 - 6813
(2007/10/03)
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- Radical-mediated synthesis of substituted quinones with organotellurium compounds
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Carbon-centered radicals generated from the corresponding organotellurium compounds react with a variety of quinones under photo-thermal conditions to give the monoaddition product in good to excellent yield. The reaction can be used for the synthesis of polyprenyl quinoid natural products.
- Yamago, Shigeru,Hashidume, Masahiro,Yoshida, Jun-Ichi
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p. 1234 - 1235
(2007/10/03)
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