• 제목/요약/키워드: Photoreaction

검색결과 82건 처리시간 0.019초

Photoreaction of 1,4-Diphenyl-1,3-butadiyne and 1,4-Di-t-butyl-1,3-butadiyne with Some Olefins

  • Shim, Sang-Chul;Kim, Sung-Sik
    • Bulletin of the Korean Chemical Society
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    • 제6권3호
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    • pp.153-157
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    • 1985
  • A diacetylene compound, 1,4-diphenyl-1,3-butadiyne, was photolyzed with 2,3-dimethyl-2-butene, 1,4-cyclohexadiene, dimethyl fumarate, and methyl crotonate, as a model reaction of the phototoxic conjugated polyynes with DNA or RNA and [2 + 2] photocycloadducts were obtained except for 1,4-cyclohexadiene. In the photoreaction of 1,4-diphenyl-1,3-butadiyne with 2,3-dimethyl-2-butene, a [2 + 2 + 2] photoadduct was additionally obtained. The photolysis of 1,4-di-t-buyl-1,3-butadiyne with 2,3-dimethyl-2-butene also yielded a [2 + 2] photoadduct. Fluorescence was observed from all the photoadducts while the reactants did not show any fluorescence.

Photoreactions of (2-Alkoxymethylphenyl)pentamethyldisilanes

  • Park, Seung-Ki
    • Bulletin of the Korean Chemical Society
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    • 제27권9호
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    • pp.1305-1309
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    • 2006
  • Photolysis of (2-hydroxymethylphenyl)pentamethyldisilane 1 in methanol provides a novel intramolecular photoproduct 4 via silene intermediate 2 but the photoreaction of (2-acetoxymethyl- or allyloxymethylphenyl) pentamethyldisilanes 5 or 10 in methanol affords unexpected photoproducts 8 or 13, respectively, instead of expected intramolecular photoproducts.

Photoreaction of 1-(o-Allyloxyphenyl)-2-pentamethyldisilanylethyne with Methanol or Acetone

  • 심상철;박승기
    • Bulletin of the Korean Chemical Society
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    • 제19권6호
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    • pp.686-689
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    • 1998
  • Irradiation of 1-(o-allyloxyphenyl)-2-pentamethyldisilanylethyne (2) in methanol yields two 1 : 1 photoaddition products (3 and 4) via silacyclopropene intermediate. Photolysis of (2) with acetone in deaerated methylene chloride yields site specific and regioselective 1: 1 adducts (7 and 8) via silacyclopropene and 1-sila-1,2-propadiene intermediate, respectively.

Synthesis of 6,13-Bis(thymidinyl)-5,12-dioxocyclams and the Molecular Structure of the (R,S)-Isomer

  • 박재욱;Louis S. Hegedus;Melissa Hellman
    • Bulletin of the Korean Chemical Society
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    • 제20권8호
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    • pp.917-920
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    • 1999
  • The three stereoisomers of the 6,13-bis(thymidinyl)dioxocyclam 6 were synthesized through photoreaction of the chromium alkoxycarbene complex 2 and 1-(benzyloxycarbonyl)-4,4-dimethyl-D 2 -imidazoline. The molecular structure of (R,S)-6 was elucidated by X-ray crystallography.

[Cr(NH$_3$)$_5$CN]$^{2+}$이온의 광반응 경로에 대한 이론적 고찰 (Theoretical Studies on the Photoreaction Paths of the Monocyanopentaamminechromium(Ⅲ) Ion)

  • 정종재;최종하
    • 대한화학회지
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    • 제29권1호
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    • pp.38-44
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    • 1985
  • [Cr(NH$_3$)$_5$CN]$^{2+}$ 이온의 광반응에서 실험적으로 관측된 생성물의 비와 이론적인 분석에 의하여 경로를 추정하였다. 각중첩모형을 이용하여 선정된 반응 좌표에 따라 생기는 여러가지 중간체에 대하여 d-궤도 함수를 분석하고 4중항 상태의 에너지 준위도 결정하였다. 적도 방향의 NH$_3$ 리간드가 떨어지면 CN-리간드가 수평 자리에 배위하는 square pyramid 중간체가 되고 이것이 N-Cr-CN bending 과정에 의하여 재배열되어 CN-리간드가 적도 방향에 위치하는 trigonal bipyramid 중간체가 된다음 이어서 적도방향의 삼각면에 있는 한 모서리로 용매분자가 측면 공격을 하여 회합하는 것으로 가정하여 실험 결과와 부합되는 결과를 얻었다.

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Photocyclization Reactions of N-(Trimethylsilylmethoxyalkyl)Phthalimides. Efficient and Regioselective Route to Heterocycles

  • Yoon Ung Chan;Oh Ju Hee;Lee, Sang Jin;Kim, Dong Uk;Lee, Jong Gun;Kang Kyung-Tae;Mariano Patrick S.
    • Bulletin of the Korean Chemical Society
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    • 제13권2호
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    • pp.166-172
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    • 1992
  • Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethoxyalkyl)phthalimides(alkyl=E thyl, n-propyl, n-butyl, n-pentyl, and n-octyl). Photocyclizations occur in methanol in high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from oxygen in the $\alpha-silylmethoxy$ groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate $\alpha-silylmethoxy$ cation radicals and cyclization by radical coupling are proposed. In contrast, photoreaction of N-(trimethylsilylmethoxyethyl) phthalimide in acetone follows different reaction routes to produce two cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon $\alpha$ to silicon and oxygen atoms via triplet carbonyl hydrogen abstraction triplet carbonyl silyl group abstraction pathways. The normal singlet SET pathway dominates these triplet processes for photoreaction of this substance in methanol. The efficient and regioselective cyclization reactions observed for photolysis in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.