• Title/Summary/Keyword: coupling reaction

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Synthesis of Pyrazinopsoralen : A Pyrazine Ring Fused Monofunctional Psoralen Derivative

  • 유동진;전영희;김동원;한규석;심상철
    • Bulletin of the Korean Chemical Society
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    • v.16 no.12
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    • pp.1212-1218
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    • 1995
  • An efficient synthesis of 6,8-dioxa-1,4-diazacyclopenta[b]phenanthren-5-one (Pyrazinopsoralen) (4) has been carried out by the Suzuki coupling reaction as a key step starting from 5-bromo-6-methoxybenzofuran (6) and methyl 2-iodo-3-pyrazinecarboxylate (8).

Oxidative Coupling of Methane by Metal Oxide Catalysts (금속 산화물 촉매를 이용한 메탄의 Oxidative Coupling 반응)

  • Kim, Hyung-Jin;Pyun, Moo-Sil;Park, Hong-Soo;Hahm, Hyun-Sik
    • Applied Chemistry for Engineering
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    • v.4 no.4
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    • pp.807-813
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    • 1993
  • Oxidative coupling of methane(OCM), one of the methods of direct methane conversion, was performed. Metal oxide catalysts used were Li/MgO and Pb/MgO. To investigate the reactivity of the catalysts with temperature, the reaction was carried out at 600, 700 and $800^{\circ}C$; and to investigate the effect of the feed ratio of the reactants($CH_4:O_2$) on reactivity, conversion, and selectivity the reaction was performed at $700^{\circ}C$ with the feed ratio of 2:1 and 1:1. The results indicate that 7wt% Li/MgO catalyst is a good catalyst for OCM reaction with 20% conversion and 65% selectivity at $700^{\circ}C$ with the feed ratio of 2:1. As feed ratio was 1:1, methane conversion was increased to 30% while $C_2$ selectivity decreased to 45% at $700^{\circ}C$ with 7wt% Li/MgO catalyst. The Pb/MgO catalyst showed less selectivity(25%) than Li/MgO did.

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Platinum-Catalyzed Reductive Aldol and Michael Reactions

  • Lee, Ha-Rim;Jang, Min-Soo;Song, Young-Jin;Jang, Hye-Young
    • Bulletin of the Korean Chemical Society
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    • v.30 no.2
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    • pp.327-333
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    • 2009
  • For the Pt-catalyzed nucleophilic addition of enones, Pt complexes were employed in the presence of various phosphine ligands and $H_2\;(or\;Et_3SiH),$ affording inter- and intra-molecular coupling products in good to modest yield. Depending on reaction protocols, different phosphine ligands were required to optimize the conditions. In the aldol reaction, the Pt catalyst involving $P(2,4,6-(OMe)_3C_6H_2)3\;or\;P(p-OMeC_6H_4)_3$ was chosen. Michael reaction proceeds in good yields in the presence of $P(p-CF_3C_6H_4)_3$. Regarding the activity of the reductants, $H_2$ exhibited superior activity to $Et_3SiH$, resulting in a shorter reaction time and higher yield in the aldol and Michael reaction. In light of the deuterium labeling studies, the catalytic cycle including the hydrometalation of the enones by the platinum hydride species was proposed.