• 제목/요약/키워드: B. Chemical Synthesis

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Synthesis and Characterization of Dense $Ti_{0.5}Zr_{0.5}B_2$ Solid Solutions by Electrically-Stimulated Combustion

  • Lee, H. B.;Kim, S. J.;Y. H. Han;J. E. Garay;Zuhair A. Munir
    • The Korean Journal of Ceramics
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    • 제6권2호
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    • pp.172-176
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    • 2000

  • Solid solutions of Ti$_{0.5}$Zr$_{0.5}$B$_2$were successfully synthesized and densified simultaneously from elemental reactants by the use of a field-activated, pressure-assisted synthesis method. The method involves the application of an electric current and mechanical pressure across reactant compacts to achieve combustion synthesis. Dense solid solutions with relative densities of up to 99% were produced and characterized by XRD, SEM, and EPMA methods. With a maximum measured temperature of 145$0^{\circ}C$ under a load of 86 MPa for 30 min, the desired dense solid solution wad synthesized.

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Concise Synthesis of (±)-Rhinacanthin A, Dehydro α-Lapachone, and β-Lapachone, and Pyranonaphthoquinone Derivatives

  • Wang, Xue;Chen, Ye;Lee, Yong-Rok
    • Bulletin of the Korean Chemical Society
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    • 제32권1호
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    • pp.153-156
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    • 2011

  • A concise synthesis of (${\pm}$)-rhinacanthin A is achieved in two steps by epoxidation of dehydro-$\alpha$-lapachone, followed by chemo- and regioselective reduction. Dehydro-$\alpha$-lapachone was also synthesized in two steps starting from 4-methoxy-1-naphthol by ethylenediamine diaetate (EDDA)-catalyzed benzopyran formation and a CAN-mediated oxidation reaction. $\beta$-Lapachone was synthesized in three steps from 4-methoxy-1-naphthol by benzopyran formation, catalytic hydrogenation, and Jones oxidation. As additional reactions, synthesis of pyranonaphthoquinone derivatives with the pyranokunthone B skeleton has been achieved in a single step from readily available 2-hydroxy-6-methoxy-1,4-naphthoquinone and 2-hydroxy-7-methoxy-1,4-naphthoquinone.

  • https://doi.org/10.5012/bkcs.2011.32.1.153 인용 PDF KSCI