• 제목/요약/키워드: [2+2] Cycloaddition

검색결과 148건 처리시간 0.028초

Synthesis and Cycloaddition Reaction of C-(2-naphthoyl)-N-arylmethanohydrazonoylpyridinium Bromides

  • Hassaneen, Hamdi M.;Shawali, Ahmad S.;Elwan, Nehal M.;Abounada, Nada M.;Algharib, Mohammed S.
    • Archives of Pharmacal Research
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    • 제15권4호
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    • pp.292-297
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    • 1992
  • Coupling of naphthacylpyridinium bromide 2 [1-(2-naphthyl) ethanone-2-pyridinium bromide] with N-nitrosoacetarylamides afforded C-(2-naphthoyl)-N-arylmethanohydrazonoylpyridinium bromides 3A-C. Treatment of 3A-C with base afforded the corresponding tetrazines 6A-C. Cycloaddition of nitrilimines 5A-C to N-arylmaleimides, acrylonitrile, ethyl acrylate, acrylamide, fumaronitrile, $\alpha$-cyanocinnamonitriles, ethyl $\alpha$-cyano-p-nitrocinnamates and $\alpha$-cyano-p-nitrocinnamamide afforded the corresponding cycloadducts 7-14, respectively. The cycloadducts 11-14 undergo a facile thermal elimination of hydrogen cyanide to give the corresponding pyrazoles 18-21 respectively.

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New Synthesis of Perhydrotriazolotriazoles Catalyzed by TiCl4 under Ambient Conditions

  • Safari, J.;Gandomi-Ravandi, S.;Ghotbinejad, M.
    • 대한화학회지
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    • 제56권1호
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    • pp.78-81
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    • 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.

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

  • 심재후
    • 대한화학회지
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    • 제13권1호
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    • pp.89-95
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    • 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.

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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
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    • 제32권1호
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    • pp.89-94
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    • 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.
    • 대한화학회지
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    • 제47권6호
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    • pp.591-596
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    • 2003
  • 아미노싸이에노피리다진(1a, b)과 아미노싸이에노쿠마린(2)은 DMFDMA와 축합반응을 하여 아미딘(3a, b)을 형성한다. 이 화합물들을 N-페닐말레이마이드와 반응시키면 화합물 9와 10이 얻어진다. 반면에 3a, b, 4, 18, 19, 20을 말레산 무수물과 반응시키면 포밀 유도체인 5a, b, 6, 21, 22, 23 들이 얻어진다. 아미딘 화합물 3a, b 를 다이에틸 퓨마레이트와 반응시키면 가수분해산물인 아미딘 14를 거쳐 11이 얻어진다. N-페닐말레이마이드를 마이크로웨이브 오븐에서 반응시키면 [2+2]와 [2+2+2] 고리첨가반응 산물이 얻어진다.