- Heterocyclic Iodoniums for the Assembly of Oxygen-Bridged Polycyclic Heteroarenes with Water as the Oxygen Source
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A diverse set of novel heterocyclic iodoniums was synthesized for the first time. The reactions of these unique iodoniums with environmentally benign water as the oxygen source provided structurally complex oxygen-incorporated heteropolycycles that are essential motifs in natural products and biologically active compounds. The transformation only required low-cost copper acetate. Further derivatization of the obtained polycycles expanded the structural diversity, which is important in the building of chemical libraries for drug discovery.
- Zhu, Daqian,Wu, Zhouming,Luo, Bingling,Du, Yongliang,Liu, Panpan,Chen, Yunyun,Hu, Yumin,Huang, Peng,Wen, Shijun
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p. 4815 - 4818
(2018/08/24)
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- Hypervalent iodine compound containing heterocyclic ring as well as preparation method and application thereof
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The invention discloses a hypervalent iodine compound containing a heterocyclic ring as well as a preparation method and application thereof. A structure of the compound is shown as a formula (I): theformula (I) is shown in the description, wherein R is selected from hydrogen, halogen, alkyl, alkoxy, halogenated alkyl, halogenated alkoxy, nitryl, cyano, hydroxyl or -COOR'; R' is alkyl or halogenated alkyl; and Het is substituted or non-substituted 1,4-benzopyranone, substituted or non-substituted quinolone, substituted or non-substituted isoquinoline, substituted or non-substituted thiobenzopyranone, substituted or non-substituted coumarin and substituted or non-substituted oxepin. The compound disclosed by the invention is novel in structure and is the hypervalent iodine compound containing the heterocyclic ring; the hypervalent iodine compound is stable in structure and simple in preparation method; and meanwhile, the hypervalent iodine compound has a very good inhibition effect onML-1 and MOLM-13 cells and has an extremely great application prospect on prevention and/or treatment effect on leukemia.
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- Iodine-mediated direct synthesis of 3-iodoflavones
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Molecular iodine has been used for the regioselective, one pot, direct synthesis of 3-iodoflavones from 2′-allyloxy chalcones, 2′-hydroxy chalcones and flavones. Allyl deprotection, cyclization dehydrogenation and α-iodination of 2′-allyloxychalcones has been achieved in a single step to offer 3-iodoflavones.
- Patil, Avinash M.,Kamble, Dayanand A.,Lokhande, Pradeep D.
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supporting information
p. 1299 - 1307
(2018/04/05)
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- Photo-induced tandem cyclization of 3-iodoflavones with electron rich five-membered heteroarenes
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Vinyl radicals were generated from 3-iodoflavones under a mercury lamp and tandem cyclization reactions occurred with five-membered heteroarenes entailing two consecutive C-C bond formations to synthesize benzo[e]chromeno[2,3-g]indol-13(1H)-one derivatives. The tandem cyclization reactions worked in acetonitrile without any additives such as transition metals, ligands and oxidants, giving rise to a broad variety of novel polycyclic xanthone frameworks in good yield under mild and environmentally friendly reaction conditions.
- Yang, Qian,Wang, Rui,Han, Jie,Li, Chenchen,Wang, Tao,Liang, Yong,Zhang, Zunting
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p. 43206 - 43211
(2017/09/15)
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- New gas-phase domino processes leading to benzopyranones and benzofurans
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A new domino approach to flavones by gas phase pyrolysis of β,γ-dioxophosphonium ylides containing a 2-methoxyphenyl group is frustrated by unexpected and novel decarbonylation of the intermediate flavon-3-yl radical leading to 2-phenylbenzofuran. Alternative approaches based on dioxolane protection of one carbonyl, or selective elimination in β,β′-dioxo or β-oxo-β′-thioxo ylides were not successful, but pyrolysis of a β-oxo-β′-phenylimino ylide did give the required domino reaction leading to a protected benzopyranone in moderate yield.
- Aitken, R. Alan,Chang, Da
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p. 164 - 184
(2017/03/11)
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- Cobalt-Catalyzed Annulation of Salicylaldehydes and Alkynes to Form Chromones and 4-Chromanones
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A unique cobalt(I)-diphosphine catalytic system has been identified for the coupling of salicylaldehyde (SA) and an internal alkyne affording a dehydrogenative annulation product (chromone) or a reductive annulation product (4-chromanone) depending on the alkyne substituents. Distinct from related rhodium(I)- and rhodium(III)-catalyzed reactions of SA and alkynes, these annulation reactions feature aldehyde C-H oxidative addition of SA and subsequent hydrometalation of the C=O bond of another SA molecule as common key steps. The reductive annulation to 4-chromanones also involves the action of Zn as a stoichiometric reductant. In addition to these mechanistic features, the CoI catalysis described herein is complementary to the RhI- and RhIII-catalyzed reactions of SA and internal alkynes, particularly in the context of chromone synthesis.
- Yang, Junfeng,Yoshikai, Naohiko
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p. 2870 - 2874
(2016/02/27)
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- Synthesis of 2-substituted 3-iodo-4H-chromen-4-ones
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3-Iodochromones containing phenyl and furyl fragments at position 2 were synthesized by heterocyclization of β-ketoenamines.
- Myannik,Yarovenko,Krayushkin,Levchenko
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p. 543 - 545
(2015/01/08)
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- Synthesis and antifungal activities of natural and synthetic biflavonoids
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The synthesis of some natural and synthetic biflavonoids was performed in good overall yields starting from readily available materials via high yielding aldol and Ullmann condensations. Some of these compounds, especially bichalcones, display an interesting activity against fungi, higher than that of the corresponding monomers.
- Sagrera, Gabriel,Bertucci, Ana,Vazquez, Alvaro,Seoane, Gustavo
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supporting information; experimental part
p. 3060 - 3073
(2011/06/27)
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- Copper-free Sonogashira coupling of acid chlorides with terminal alkynes in the presence of a reusable palladium catalyst: An improved synthesis of 3-iodochromenones (= 3-iodo-4H-1-benzopyran-4-ones)
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Pd/C is used as an efficient catalyst for the copper-free Sonogashira coupling of acid chlorides and terminal alkynes to afford ynones in high yields (Tables 1 and 3). Cyclization of (2-methoxyaryl)-substituted ynones induced by I2/ammonium cer
- Likhar, Pravin R.,Subhas,Roy, Moumita,Roy, Sarabindu,Kantam, M. Lakshmi
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experimental part
p. 259 - 264
(2009/02/07)
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- Synthesis, characterization, and estrogen receptor binding affinity of flavone-, indole-, and furan-estradiol conjugates
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Different flavone-, indole-, and furan-17β-estradiol conjugates, linked via alkyl spacer chains extending from the 17α-position of the estradiol moiety, were synthesized by Pd-catalyzed cross-coupling reactions. Structures were assigned based on spectrosc
- Ahmed, Naseem,Dubuc, Celena,Rousseau, Jacques,Benard, Francois,van Lier, Johan E.
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p. 3212 - 3216
(2008/02/05)
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- Diversity-oriented synthesis of 3-iodochromones and heteroatom analogues via ICl-induced cyclization
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The ICl-induced cyclization of heteroatom-substituted alkynones provides a simple, highly efficient approach to various 3-iodochromones and analogues. This process is run under mild conditions, tolerates various functional groups, and generally provides chromones in good to excellent yields. Subsequent palladium-catalyzed transformations afford a rapid increase in molecular complexity and a convenient preparation of a wide range of functionally substituted chromones, furans, and polycyclic compounds. Iodothiochromenones and iodoquinolinones are also prepared by similar ICl-induced cyclizations.
- Zhou, Chengxiang,Dubrovsky, Anton V.,Larock, Richard C.
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p. 1626 - 1632
(2007/10/03)
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- Synthesis of fused polycyclic aromatics by palladium-catalyzed annulation of arynes using 2-halobiaryls
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The Pd-catalyzed annulation of arynes by 2-halobiaryls and related vinylic halides provides a very efficient, high yielding synthesis of polycyclic aromatic and heteroaromatic hydrocarbons. This process appears to involve the catalytic, stepwise coupling
- Liu, Zhijian,Zhang, Xiaoxia,Larock, Richard C.
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p. 15716 - 15717
(2007/10/03)
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- Synthesis of 3-iodo derivatives of flavones, thioflavones and thiochromones
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The title compounds, 2-aryl-3-iodo-4H-1-benzopyrans and 2-alkyl or 2-aryl-3-iodo-4H-1-benzothiopyrans, were prepared by reaction of the corresponding heterocyclic derivatives with the iodine-cerium(IV) ammonium nitrate system under mild conditions. The scope and proposed mechanism of the reaction were also demonstrated.
- Zhang,Li
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p. 565 - 567
(2007/10/02)
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- Lithiation in Flavones, Chromones, Coumarins, and Benzofuran Derivatives
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Flavones are lithiated at position 3 by lithium di-isopropylamide in tetrahydrofuran at -78 deg C and the products are stable at that temperature.Appropriate reagents replace the lithium by carboxy, ethoxycarbonyl, mercapto, methylthio, trimethylsilyl, hydroxy, and other groups, sometimes giving products not previously available.Benzofurans are preferentially lithiated at position 2 if this is free, and may not be attacked if it is blocked, but if there is an activating group (i.e., one able to co-ordinate with the lithium cation) at position 2, then lithiation occurs at position 3.In the benzofuran series ring-opening is easier and lithiation often leads directly to acetylenic phenols.Chromones can be lithiated at positions 2 and 3 depending upon the substitution pattern and whether the substituents are activating.Aurones are not easily deprotonated, and only the acetylenic phenol arising from ring opening was found in the one successful case.Coumarins tend to behave simply as esters and give amides with the lithiating reagent, but 4-methoxycoumarin is readily lithiated at position 3.It is suggested that 3-deprotonation in ethers occurs easily only when there is an ether link antiperiplanar to the proton removed, and that the lithiated species are really unstable intermediates in trans-eliminations leading to alkyne derivatives.
- Costa, Ana M. B. S. R. C. S.,Dean, Francis M.,Jones, Michael A.,Varma, Rajender S.
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p. 799 - 808
(2007/10/02)
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