• Title, Summary, Keyword: Synthesis

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Efficient Synthesis of An Epoxy Alcohol, A key Intermediate for$LTA_4$ Synthesis

  • Hokoon Park;Yong Sup Lee;Sang Chul Shim
    • Bulletin of the Korean Chemical Society
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    • v.13 no.5
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    • pp.551-553
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    • 1992
  • An efficient and very short synthesis of epoxy alcohol 5, a key intermediate for leukotriene synthesis, was described. The key reaction involves the regioselective benzylidene acetal formation from methyl 5,6,7-trihydroxyheptanoate 1.

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Synthesis of Melandrin (Melandrin의 합성)

  • 문정술;이강노;임중기;우원식
    • YAKHAK HOEJI
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    • v.35 no.4
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    • pp.332-334
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    • 1991
  • The synthesis of melandrin has been accomplished in good yield by the reaction of 5-tosyloxyanthranilic acid ethyl ester with p-acetoxybenzoyl chloride, followed by removal of protecting groups with methanolic ammonia.

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New Tactics for Stereospecificity in Metallocene-based Olefin Polymerization

  • Kim, Seong-Kyun;Park, Sung-Jin;Kim, Hwa-Kyu;Yoon, Seung-Woong;Lee, Jun-Seong;Park, Myung-Hwan;Do, Young-Kyu
    • Proceedings of the Polymer Society of Korea Conference
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    • pp.221-221
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    • 2006
  • The stereochemical control in polypropylenes and styrene-ethylene copolymers based on homogeneous single-site polymerization catalysts has received great attention since the stereocpecificity is one of the key factors in tailoring the polymer properties. Thus, we have developed new tactics for isospecificity in propylene polymerization with the unbridged metallocenebased systems and syndiospecific styrene-styrene sequence in styrene-ethylene copolymerization with the group 4 metallocene system. Brief details of the synthesis, structures and the polymerization behavior of a set of new metallocene catalysts will be presented.

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Solid-phase Synthesis of 7-Aryl-benzo[b][1,4]oxazin-3(4H)-one Derivatives on a BOMBA Resin Utilizing the Smiles Rearrangement

  • Lee, Ji-Min;Yu, Eun-Ae;Park, Joo-Yeon;Ryu, In-Ae;Shin, Dong-Soo;Gong, Young-Dae
    • Bulletin of the Korean Chemical Society
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    • v.30 no.6
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    • pp.1325-1330
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    • 2009
  • A general method has been developed for the solid phase synthesis of drug-like 7-aryl-benzo[b][1,4]oxazin-3(4H)- one derivatives 6. The method relies on a novel, microwave irradiation promoted cyclization reaction of the BOMBA resin bound, N-substituted-$\alpha$-(2-chloro-4-bromophenoxy)acetamide 3 that takes place via a Smiles rearrangement. The 7-bromobenzo[1,4]oxazine 4, produced in this process is converted to 7-aryloxazin analogs 5 by utilizing Suzuki coupling with various substituted arylboronic acids. Finally, the target 7-aryl-benzo[b][1,4]oxazin-3(4H)-ones 6 are liberated from the resin by treatment with 5% TFA. The progress of the reactions involved in this preparative route can be monitored by using ATR-FTIR spectroscopy on a single bead. The target compounds, obtained by using this five-step sequence, are produced in high yields and purities.

SYNTHESIS OF NANO-SIZED IRON FOR REDUCTIVE DECHLORINATION. 2. Effects of Synthesis Conditions on Iron Reactivities

  • Song, Ho-Cheol;Carraway, Elizabeth R.;Kim, Young-Hun
    • Environmental Engineering Research
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    • v.10 no.4
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    • pp.174-180
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    • 2005
  • Nano-sized iron was synthesized using borohydride reduction of $Fe^{3+}$ in aqueous solution. A wide range of synthesis conditions including varying concentrations of reagents, reagent feeding rate, and solution pH was applied in an aqueous system under anaerobic condition. The reactivity of nano-sized iron from each synthesis was evaluated by reacting the iron with TCE in batch systems. Evidence obtained from this study suggest the reactivity of iron is strongly dependent on the synthesis solution pH. The iron reactivity increased as solution pH decreased. More rapid TCE reduction was observed for iron samples synthesized from higher initial $Fe^{3+}$ concentration, which resulted in lower solution pH during the synthesis reaction. Faster feeding of $BH_4^-$ solution to the $Fe^{3+}$ solution resulted in lower synthesis solution pH and the resultant iron samples gave higher TCE reduction rate. Lowering the pH of the solution after completion of the synthesis reaction significantly increased reactivity of iron. It is presumed that the increase in the reactivity of iron synthesized at lower pH is due to less precipitation of iron (hydr)oxides or less surface passivation of iron.