• Title/Summary/Keyword: Photoreactions

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Studies on the Photoreactions of Coumarins and Furocoumarins (쿠마린과 푸로쿠마린의 광화학반응에 관한 연구)

  • Shim Sang Chul;Im Kyung Ran
    • Journal of the Korean Chemical Society
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    • v.20 no.3
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    • pp.236-239
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    • 1976

  • The mechanism of skin-sensitizing photoreactions of coumarins and furocoumarins are studied by spectroscopic, triplet quenching, and fluorescence techniques. The excited singlet mechanism is suggested for xanthotoxin-thymine/or DNA photoreactions from the results of triplet quenching studies utilizing ${\beta}$-carotene as a quencher.

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An Intramolecular Photosubstitution Reaction of N-(2,4-Dibromonaphthyl)- arenecarboxamide: Synthesis of 2-Arylnaphthoxazole

  • Bae, In-Soo;Kim, Yoo-Shin;Park, Yong-Tae
    • Bulletin of the Korean Chemical Society
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    • v.24 no.7
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    • pp.916-920
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    • 2003

  • Photoreactions of N-(2,4-dibromonaphthyl)arenecarboxamides in basic medium result in the intramolecular substituted products, 2-aryl-8-bromonaphthoxazoles in moderate yields and further photoreactions of the products afford the reduced products, 2-arylnaphthoxazoles. These reactions are straightforward for syntheses of naphthoxazole derivatives. Since the intramolecular photosubstitution of the bromoarenecarboxamide by the oxygen of its amide group is more effective than the photoreduction of the substituted product, 2-aryl-8- bromonaphthoxazole in basic medium, the intramolecular substituted product, 2-aryl-8-bromonaphthoxazole can be isolated. A charge-transfered excited singlet state of an imidol form of the 2-bromoarenecarboxamide is involved in the photosubstitution, whereas an excited triplet state of the 2-aryl-8-bromonaphthoxzole is closely involved in the photoreduction.

  • https://doi.org/10.5012/bkcs.2003.24.7.916 인용 PDF KSCI

Photoreactivity of $ReH_5$(Cyttp) (Cyttp=Php$(CH_2CH_2CH_2PCy_2)_2)$ with CO, $CO_2\;and\;PMe_3$

  • Lee, Myung-Young;Shin, Dae-Ho;Kim, You-Hyuk
    • Bulletin of the Korean Chemical Society
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    • v.15 no.7
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    • pp.571-576
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    • 1994

  • The photoreactions of $ReH_5(Cyttp)\;(1)\;(Cyttp=PhP(CH_2CH_2CH_2PCy_2)_2)\;with\;CO,\;CO_2\;and\;PMe_3 has been investigated to find the differences in reactivities from those of trismonophosphine analog. Irradiation of 1 under CO, $CO_2$ and excess $PMe_3$ in benzene results in the formation of the complexes, $ReH(CO)_2(Cyttp)\;(2),\;ReH_2({\eta}^2-HCO_2)(Cyttp)\;(3)\;and\;$ReH_3(PMe_3)(Cyttp)$ (4), respectively. The resulting products suggest that photoreactions of $ReH_5(Cyttp)$ proceed by photoextrusion of $H_2$ giving a phototransient species "$ReH_3$(Cyttp)" which can be trapped by CO, $CO_2\;and\;PMe_3$. The structures of 2, 3 and 4 are inferred based on $^1H,\;^{31}P$ NMR and I. R spectroscopy.

  • https://doi.org/10.5012/bkcs.1994.15.7.571 인용 PDF

Photoreactions of (2-Alkoxymethylphenyl)pentamethyldisilanes

  • Park, Seung-Ki
    • Bulletin of the Korean Chemical Society
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    • v.27 no.9
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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.

  • https://doi.org/10.5012/bkcs.2006.27.9.1305 인용 PDF KSCI