• Title/Summary/Keyword: [2+2+2] Cycloaddition

Search Result 148, Processing Time 0.018 seconds

New Synthesis of Perhydrotriazolotriazoles Catalyzed by TiCl4 under Ambient Conditions

  • Safari, J.;Gandomi-Ravandi, S.;Ghotbinejad, M.
    • Journal of the Korean Chemical Society
    • /
    • v.56 no.1
    • /
    • pp.78-81
    • /
    • 2012
  • Aromatic 2,3-diazabuta-1,3-dienes in glacial acetic acid with isothiocyanate in the presence of catalyst $TiCl_4$ at room temperature produced via criss-cross cycloaddition reactions the corresponding perhydro[1,2,4]triazolo[1,2-a][1,2,4] triazole-1,5-dithiones in relatively high yields and short reaction time.

Studies on Tropolones (Ⅲ) Structures and Reaction Mechanisms of the Adducts of Dichloroketene and Cyclopentadienes (Tropolone 類에 關한 硏究 (III) Dichloroketene과 Cyclopentadiene 類의 添加物의 構造와 그 反應機構)

  • Jae Hu Shim
    • Journal of the Korean Chemical Society
    • /
    • v.13 no.1
    • /
    • pp.89-95
    • /
    • 1969
  • The structural investigations on the adducts, formed from dichloroketene with cyclopentadiene, methyl and ethylcyclopentadiene, have been carried out by means of infrared and nuclear magnetic resonance spectroscopy and also by their chemical behaviors. It was confirmed by this study that the adducts were formed by 1, 2-cycloaddition reaction and had the fundamental structure of bicyclo [3. 2. 0]-7,7-dichloro-2-heptene-6-one. These results were well agreed with the hypothesis that a diradical intermediate was formed as the first step in 1, 2-cycloaddition. The reaction mechanism for the process in which tropolones were formed from these adducts was also discussed.

  • PDF

Ab Initio Study of Mechanism of Forming Germanic Bis-Heterocyclic Compound between Dimethyl-Germylene Carbene (Me2Ge=C:) and Acetone

  • Lu, Xiuhui;Che, Xin;Lian, Zhenxia;Li, Yongqing
    • Bulletin of the Korean Chemical Society
    • /
    • v.32 no.1
    • /
    • pp.89-94
    • /
    • 2011
  • The mechanism of the cycloaddition reaction of forming germanic bis-heterocyclic compound between singlet dimethylgermylene carbene and acetone has been investigated with CCSD(T)//B3LYP/6-$31G^*$ method. From the potential energy profile, it can be predicted that, this reaction has one dominant channel. The presented rule of this dominant channel is that the two reactants firstly form a four-membered ring carbene (RC4) through the [2+2] cycloaddition reaction. Due to $sp^2$ hybridization of carbene C atom in RC4, RC4 further combines with acetone to form a reactant complexe (RC5). Due to the further $sp^3$ hybridization of carbene C atom in RC4, RC5 isomerizes to a germanic bisheterocyclic compound (P6) via the transition state (TS5).

Microwave Assisted Reaction of Condensed Thiophenes With Electron Poor Olefins

  • Al-zaydi, Khadijah M.;Elnagdi , Mohamed H.
    • Journal of the Korean Chemical Society
    • /
    • v.47 no.6
    • /
    • pp.591-596
    • /
    • 2003
  • Aminothienopyridazines 1a, b and aminothienocoumarin 2 condensed with DMFDMA to yield amidines 3a, b and 4. These compounds reacted with N-phenylmaleimide to yield 9 and 10. On the other hand reacting 3a, b, 4, 18, 19 and 20 with maleic anhydride afforded only the formylated derivatives 5a, b, 6, 21, 22 and 23 respectively. The reaction of 3a, b with diethyl fumarate afforded 11, formed most likely via hydrolysis of the amidine 14 during working up the reaction mixture. Irradiation of N-phenylmaleimide in microwave oven afforded [2+2] and [2+2+2] cycloaddition product.

Nanocrystalline Copper Oxide(II)-Catalyzed Alkyne-Azide Cycloadditions

  • Song, Young-Jin;Yoo, Chung-Yul;Hong, Jong-Tai;Kim, Seung-Joo;Son, Seung-Uk;Jang, Hye-Young
    • Bulletin of the Korean Chemical Society
    • /
    • v.29 no.8
    • /
    • pp.1561-1564
    • /
    • 2008
  • Although the use of Cu(II) salts as catalysts without reductants is limited in the cycloaddition of acetylenes with azides, the catalytic system employing average 10 nm CuO(II) nanoparticles in the absence of reductants shows good catalytic activity to form 1,4-disubstituted 1,2,3-triazoles even in wet THF as well as water. It is also noticeable that CuO(II) nanoparticle catalysts can be recycled with consistent activity. A range of alkynes and azides were subject to the optimized CuO(II) nanoparticle-catalyzed cycloaddition reaction conditions to afford the desired products in good yields.