• Title/Summary/Keyword: isomeric

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Friedel-Crafts Type alkylation of 1,2,3,4,5,6,7,8,-Octahydroanthracene with Vinylchlorosilanes:Synthesis of Mono,Bis[2-(chlorosilyl)ethyl]-1,2,3,4,5,6,7,8,-Octahydroanthracenes

  • Gong, Seong-Deok;Lee, Chang-Yeob;Yoo, Bok-Ryul;Lee, Myong-Euy;Jung, Il-Nam
    • Bulletin of the Korean Chemical Society
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    • v.23 no.9
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    • pp.1213-1221
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    • 2002
  • Friedel-Crafts alkylation reaction of an isomeric mixture of 1,2,3,4,5,6,7,8- (2) and 1,2,3,4,5,6,7,8-octahydrophenanthrene (2') with excess vinylchlorosilanes such as vinyl(methyl)dichlorosilane (1a) and vinyltrichlorosilane (1b) in the presence of aluminum chloride catalyst at 80 $^{\circ}C$ gives only one dialkylated products, 9,10-bis[2-(chlorosilyl)ethyl]-1,2,3,4,5,6,7,8-octahydroanthrenes [(Cl2XSiCH2CH2)2C14H16: X = Me (4a), Cl (4b)] in good yields, but 9,10-bis[2-(chlorosilyl)ethyl]-1,2,3,4,5,6,7,8-octahydrophenanthrenes are not obtained. However, monoalkylation of 2 with 1 affords a mixture of both isomeric compounds, 9-[2-(chlorosilyl)ethyl]-1,2,3,4,5,6,7,8-octahydroanthracenes 3 and -phenanthrenes 3'. The yield of product 3' is always higher than that of 3. When a mixture of 3 and 3' is alkylated again with 1, only product 4 without phenanthrene type compounds is obtained, indicating that the isomerizations between 2 and 2', or 3 and 3'occur under the alkylation condition. The alkylation with dimethylvinylchlorosilane or trimethylvinylsilane did not proceed. The structure of 4a is determined by X-ray single crystal diffraction analysis.

Study on the Isomeric Ratio by Thermal Neutron Activation

  • Bak, Hae-Ill
    • Nuclear Engineering and Technology
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    • v.6 no.2
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    • pp.89-96
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    • 1974
  • The cross-section ratios of the nuclear isomeric pairs $^{80}$ B $r^{m, g}$, sup 81/S $e^{m, g}$, $^{104}$ R $h^{m, g}$, $^{116}$ I $n^{m, g}$ and $^{134}$ C $s^{m, g}$ through the radiative thermal neutron capture process have been studied. The experimental values of these ratios obtained by the activation method have been compared with the calculated ones deduced from the modified Huizenga-Vandenbosch method. Agreement between these values within 30% could be attained by controlling the spin cut-off parameter and gamma-ray multiplicity.

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Isomeric Folate-Conjugated Polymeric Micelles Bind to Folate Receptors and Display Anticancer Effects

  • Dong, Qing;Xie, Zuo-Xu;Xie, Cao;Lu, Wei-Yue;Zhang, Qian;Li, Xue;Liu, Min
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.17
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    • pp.7363-7369
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    • 2014
  • The present study aimed to prepare and evaluate polymeric micelles conjugated with folic acid through ${\alpha}$- or ${\gamma}$-carboxyl groups for antitumor efficacy. The isomeric block copolymers, ${\alpha}$- and ${\gamma}$-folate-polyethyleneglycol-distearoyl phosphatidylethanolamine (${\alpha}$- and ${\gamma}$-Fol-PEG-DSPE), were produced by solid phase peptide synthesis. Three types of doxorubicin (DOX)-loaded polymeric micelles (MPEG-DSPE-DOX and ${\alpha}$- / ${\gamma}$-Fol-PEG-DSPEDOX micelles) were prepared via the film formation method. Compared with MPEG-DSPE-DOX micelles, the ${\alpha}$- / ${\gamma}$-Fol-PEG-DSPE-DOX micelles presented a higher cellular uptake behavior in the live cell study. Cell viability percentages were 81.8%, 57.3%, 56.6% at 2 hours for MPEG-DSPE-DOX, ${\alpha}$- and ${\gamma}$-Fol-PEG-DSPE-DOX micelles, respectively (p<0.05). Using the KB xenograft tumor model, both ${\alpha}$- and ${\gamma}$-folate-conjugated micelles were found to have better antitumor effects with lower toxicity in comparison with MPEG-DSPE-DOX micelles. No difference in in vivo antitumor efficacy was found between ${\alpha}$- and ${\gamma}$-Fol-PEG-DSPE-DOX micelles. The folate-conjugated micelles might be a potentially useful strategy for tumor targeting of therapeutic agents, whether grafting with folic acid through ${\alpha}$- or ${\gamma}$-carboxyl groups.

A Study of the cis - trans Rotational Isomeric Relaxation in Methyl Acetate (광회절 초음파 공명법에 의한 methyl acetate의 회전이성 완화의 연구)

  • Bae Jong-Rim
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.171-174
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    • 1999
  • Methyl acetate의 초음파 흡수측정을 0.2-10MHz의 주파수 범위, 은도 5-30에 걸쳐 광회절 초음파 공명법을 사용하여 행하였다. 그 결과, cis와 trans에 의한 완화는 단일 완화현상을 보였고 그 스책트럼으로 부터 완화 주파수와 완화강도를 결정하였다. 완화 주파수의 온도 의존성으로부터 활성화 에너지(${\Delta}H^{#}$)=6.6 kcal/mol을, 완화강도의 온도 의존성에서 엔탈피차(${\Delta}H$)=3.4 kcal/mol을 각각 구하였다.

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Cyclo-depolymerization of Poly (ethylene Terephthalate-co-ethylene Isophthalate)s (폴리에틸렌테레프탈레이트-코-에틸렌이소프탈레이트의 고리해중합)

  • Yoo, Dong-Il;Lee, Eung-Eui;Shin, Youn-Sook
    • Textile Coloration and Finishing
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    • v.10 no.1
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    • pp.20-24
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    • 1998
  • Oligomeric extracts of poly(ethylene terephthalate-co-ethylene isophthalate)s [(PET/EI] are analyzed by high performance liquid chromatography(HPLC) and nuclear magnetic resonance spectroscopy (NMR). Existence of separated peaks for small cyclics of trimer and tetramer gives the existence of structural isomeric forms. NMR confirms that cyclization of PET/EI occurs more easily at the site of isophthaloyl unit.

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