• Title/Summary/Keyword: cycloaddition

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Facile Formation of Unexpected [m,6,n]-tricyclic Spiranes via Intramolecular [3+2] Cyclization of Platinum-bound Pyrylium with Alkenes

  • Oh, Chang-Ho;Tak, Sang-Yong;Lee, Ji-Ho;Piao, Lanhua
    • Bulletin of the Korean Chemical Society
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    • v.32 no.spc8
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    • pp.2978-2980
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    • 2011
  • Enynals bearing an olefinic pendant were successfully cyclized via Huisgen-type [3+2] cycloaddition to the tetracyclic Pt-carbene complexes which would undergo insertion into a C-H bond of the ${\beta}$-position to afford the fused cyclopropane intermediates. Their tandem rearrangement afforded diverse types of spiranes depending on the tethered alkenes of the enynals.

Azide/Alkyne Resins for Quick Preparation of 1,4-Disubstituted 1,2,3-Triazoles

  • Sirion, Uthaiwan;Lee, Jae-Hak;Bae, Yu-Jin;Kim, Hee-Jun;Lee, Byoung-Se;Chi, Dae-Yoon
    • Bulletin of the Korean Chemical Society
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    • v.31 no.7
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    • pp.1843-1847
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    • 2010
  • An efficient method for the preparation of 1,4-disubstituted 1,2,3-triazole compounds is described using polymeric quaternary ammonium salts having azide or alkyne functionality to remove unreacted excess starting molecules (azide/alkyne). Copper metal could easily be removed by simple filtration with a short $Na_2SO_4$/silica cartridge, affording highly regioselective products in high yield and excellent purity without the need for work-up, extraction and chromatographic purification.

Antimalarial Activity of C-10 Substituted Triazolyl Artemisinin

  • Park, Gab-Man;Park, Hyun;Oh, Sangtae;Lee, Seokjoon
    • Parasites, Hosts and Diseases
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    • v.55 no.6
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    • pp.661-665
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    • 2017
  • We synthesized C-10 substituted triazolyl artemisinins by the Huisgen cycloaddition reaction between dihydroartemisinins (2) and variously substituted 1, 2, 3-triazoles (8a-8h). The antimalarial activities of 32 novel artemisinin derivatives were screened against a chloroquine-resistant parasite. Among them, triazolyl artemisinins with electron-withdrawing groups showed stronger antimalarial activities than those shown by the derivatives having electron-donating groups. In particularly, m-chlorotriazolyl artemisinin (9d-12d) showed antimalarial activity equivalent to that of artemisinin and could be a strong drug candidate.

Photochemistry of 1-(o-substituted -phenyl)-2-pentamethyldishilanyl Ethynes

  • Shim, Sang-Chul;Park, Seung-Ki
    • Journal of Photoscience
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    • v.6 no.1
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    • pp.13-19
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    • 1999
  • Irradiation of 1-(o-allyloxyphenyl)-2-pentamethyldisilanylenthyne 2a in methanol yields two 1 : 1 photoaddition products 3 and 4 via silacyclopropene intermediate. Photolysis of 2a with acetone in deaerated methylene chloride yields site specific and regioselective 1 : 1 adducts 6 ad 7 via silacyclopropene and 1-sila-1, 2-propdiene intermediate, respectively. Photolysis of 2a and 1-(o-(3', 3'-dimethyl-2'-propenylox)phenyl)-2-pen-tamethyldisilanylethyone 2b in benzene provides novel stereoselevtive intramolecular cyclization products 10 and 11, respectively. Irradiation of 1-(o-acetoxyphenyl)-2-pentamethyldisilanyl ethyne 2c in benzene yields the photo-Fries rearrangement products 18 and 19 and a photoproduct 17 via silacyclopropene intermediate. Photolysis of 1-(o-methoxycarbonlymethoxyphenyl)-2-pentamethyl disilanylenthyne 2d in benzene provides a novel intramolecular cycloaddition product 25 and 1-(o-methoxycarbonylemthoxiyphenyl)-2-trimethylsilylethyne 26 via silacyclopropene intermediate.

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Two different reaction mechanisms of cinnamate side groups attached to the various polymer backbones

  • Hah, Hyun-Dae;Sung, Shi-Joon;Cho, Ki-Yun;Jeong, Yong-Cheol;Park, Jung-Ki
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.772-775
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    • 2006
  • Cinnamate polymers are well known photoreactive polymers due to [2+2] cycloaddition reaction of cinnamate side group. In this work, we have found that the cinnamate side groups could be also reacted by thermal energy, and this reaction is presumed to attribute to the radical reaction of carbon double bond in the cinnamate groups. Contrary to the photocycloaddition reaction of the cinnamate side groups, the thermal reaction of cinnamate side group was closely related to the flexibility of polymer backbone. The difference of the mechanism between the photocycloaddition reaction and thermal crosslinking reaction was confirmed by $^1H-NMR$$ and $^{13}C-NMR$ analysis of the model compound.

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Quantum Mechanical Studies of the Structures and Reactions of oxiranes (Oxiranes의 구조와 반응에 관한 양자역학적 연구)

  • Shi Choon Kim
    • Journal of the Korean Chemical Society
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    • v.30 no.2
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    • pp.248-258
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    • 1986
  • The electronic structures and geometries of model substituted oxiranes, and carbonyl ylides containing cyano, methoxy and thiomethoxy substituents were investigated by MNDO-SCF-MO method. Stabilization and geometries caused by substituents, the ease of formation of carbonyl ylides from oxiranes and the reactivities of the cycloaddition of substituted carbonyl ylides were investigated.

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Synthesis of Pyrazolylquinoxalines and Pyrazolylpyrrolo[1,2-a]-quinoxalines (Pyrazolylquinoxaline류 및 Pyrazolylpyrrolo[1,2-a]-quinoxaline류의 합성)

  • Kim, Ho Sik;Lee, Seong Uk;Jeong, Won Young;Han, Sung Wook;Kim, Dong Il;Yoshihisa Kurasawa
    • Journal of the Korean Chemical Society
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    • v.45 no.4
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    • pp.318-324
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    • 2001
  • The reaction of 6-chloro-2-hydrazinoquinoxaline(4) or 6-chloro-2-hydrazinoquinoxaline 4-oxide(7) with alkyl (ethoxymethylene)cyanoacetates gave pyrazolylquinoxalines(5, 8). The reaction of compounds 8 with dimethyl acetylenedicarboxylate resulted in the 1,3-dipolar cycloaddition reaction and then ring transformation to afford pyrazolylpyrrolo[1,2-a]quinoxalines(9).

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Synthesis of Isoxazolone Derivatives from (Chlorocarbonyl)phenyl Ketene with Benzhydroxamic Acids

  • Nejadshafiee, Vajihe;Saidi, Kazem;Abaszadeh, Mehdi
    • Bulletin of the Korean Chemical Society
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    • v.32 no.12
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    • pp.4176-4178
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    • 2011
  • The reaction of (chlorocarbonyl)phenyl ketene, with readily available benzhydroxamic acid derivatives, such as benzhydroxamic acid, 4-chlorobenzhydroxamic acid, 3-nitrobenzhydroxamic acid, 4-methylbenzhydroxamic acid, N-hydroxy-3-oxo-3-phenylpropionamide, N-hydroxy-2-phenylacetamide, affords isoxazolone derivatives in high yields in a one step procedure. The formation of the products proceeds by a mechanism, that involves replacement of chlorine of the ketene, by benzhydroxamic acids, followed by rapid ring closure of this intermediate to form isoxazolone derivatives.

Development of Click Chemistry in Polymerization and Applications of Click Polymer

  • Karim, Md. Anwarul
    • Rubber Technology
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    • v.13 no.1
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    • pp.1-9
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    • 2012
  • Click chemistry had enjoyed a wealthy decade after it was introduced by K.B.Sharpless and his co-worker on 2001. Since there is no optimized method for synthesis of click polymer, therefore, this paper introduced three click reaction methods such as catalyst, non-catalyst and azide-end capping for fluorene-based functional click polymers. The obtained polymers have reasonable molecular weight with narrow PDI. The polymers are thermally stable and almost emitted blue light emission. The synthesized fluorene-based functional click polymers were characterized to compare the effect of click reaction methods on polymer electro-optical properties as well as device performance on quasi-solid-state dye sensitized solar cells (DSSCs) applications. The DSSCs with configuration of $SnO_2:F/TiO_2/N719$ dye/quasi-solid-state electrolyte/Pt devices were fabricated using these click polymers as a solid-state electrolyte components. Among the devices, the catalyzed click polymer composed device exhibited a high power conversion efficiency of 4.62% under AM 1.5G illumination ($100mW/cm^2$).These click polymers are promising materials in device application and $Cu^I$-catalyst 1, 3-dipolar cycloaddition click reaction is an efficient synthetic methodology.

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