• Title/Summary/Keyword: Regioselective

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Regioselective synthesis of .alpha.-L-fucosyl-containing benzyl disaccharides by use of .alpha.-L-fucosidases of aspergillus niger

  • Chung, Yong-Za;Kwak, Hong-Keun;Sung, Yung-Ki
    • Archives of Pharmacal Research
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    • v.19 no.4
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    • pp.307-311
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    • 1996
  • The activity of fucosidase shows different value depending on disease, eg) fucosidosis and I cell disease are characterized by the absence or deficiences of .alpha.-fucosidase, and sera of ovarian cancer patients exhibited a statistically significant deficiency of .alpha.-L-fucosidase activity (Zielke et al., 1972; Kress et al., 1980; Barlow et al., 1981). For the purpose of diagnosis of these disease easily, the manual of test can be developed by preparing kits of hydrophobic-binding substrate of fucosidase that bind C18-column.

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Functionalization of Isoflavones with Enzymes

  • Lee, Jae-Hwan;Doo, Eun-Hee;Kwon, Dae-Yong;Park, Jin-Byung
    • Food Science and Biotechnology
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    • v.17 no.2
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    • pp.228-233
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    • 2008
  • Considerable progress has been made in functionalization of the soy isoflavones through enzymatic modification of daidzin, genistin, and glycitin. After hydrolysis of $\beta$-glucosides into their corresponding aglycones, these compounds were structurally modified via biotransformations such as regioselective hydroxylation, enantioselective reduction, regioselective methylation, and polymerization. These reactions often resulted in an increase of the biological activities (e.g., anti oxidative activity, antiproliferative activity) and/or improvement of the physico-chemcial properties (e.g., water solubility, bioavailability). This review briefly summarizes on-going research activities on the biofunctionalization of the soy isoflavones.

Regioselective 1,3-Dipolar Cycloaddition and 1,2-Addition between Benzaldoxime NH-nitrone and Perfluoro-2-methyl-2-pentene

  • Lee, Chan-Woo;Park, Joo-Yuen;Kim, Hyun-Uk;Chi, Ki-Whan
    • Bulletin of the Korean Chemical Society
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    • v.31 no.5
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    • pp.1172-1176
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    • 2010
  • Regioselective perfluorinated [3+2] cycloadducts and 1,2-adducts have been prepared by 1,3-dipolar cycloaddition between benzaldoxime NH-nitrone and perfluorinated alkene, perfluoro-2-methyl-2-pentene. Although the cycloaddition reaction is carried out at room temperature, the corresponding perfluorinated compounds are effectively produced in a high yield. In particular, the methoxy-substituted adducts (4 and 7a) show the self-assembled structure by intermolecular interactions. These derivatives were characterized by IR, $^1H$ and $^{19}F$ NMR, and the absolute structure of perfluorinated adducts was confirmed by X-ray crystallography.

Highly Chemo- and Regioselective Reaction of Hydroxybenzenes in Acidic Ionic Liquid

  • Guo, Hui;Zhuang, Yu Wei;Cao, Jian;Zhang, Guo Bao
    • Bulletin of the Korean Chemical Society
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    • v.34 no.9
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    • pp.2594-2596
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    • 2013
  • Highly chemo- and regioselective reaction of hydroxybenzenes with ${\alpha},{\beta}$-unsaturated compounds in acidic ionic liquid l-butyl-3-methylimidazolium hydrogen sulphate ([BMIM]HSO4) was reported for the first time. A series of oxa-Michael adducts and Friedel-Crafts alkylated products were synthesized with good yields. The acidic ionic liquid could be easily recycled for at least 5 times with only minor loss in activity.

Thirty Six Years of Research on the Selective Reduction and Hydroboration

  • Cha, Jin-Soon
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.1808-1846
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    • 2011
  • From 1975 to 2011, for thirty six years, the author and his collaborators have developed a variety of reducing and hydroborating agents, and applied them to organic synthesis, which involves the 1,2-reduction of ${\alpha}$,${\beta}$-unsaturated carbonyl compounds, stereoselective reduction of cycloalkanones, regioselective ring-opening of epoxides, partial reduction of carboxylic acid derivatives to aldehydes, regioselective addition to carbon-carbon multiple bonds, etc. by utilizing metal hydrides and the newly-devised the Meerwein-Ponndorf-Verley (MPV) type reagents. Such developments provide a new synthetic methodology making possible valuable selective reductions and hydroborations, not practical previously.

Design and Synthesis of (${\pm}$) -3-Deoxygericudranin A as an Antitumour Agent (항암제로서의 (${\pm}$) -3-데옥시제리쿠드라닌 A의 설계 및 합성)

  • Choi, Yoon-Jung;Shim, Pil-Jong;Kim, Hee-Doo
    • YAKHAK HOEJI
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    • v.41 no.1
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    • pp.14-17
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    • 1997
  • (${\pm}$)-3-Deoxygericudranin A was designed and synthesized for the development of novel antitumour agent and for the elucidation of the effect of 3-hydroxyl group in gericudranin A on antitumour activity. 2,4.6-Trihydroxyacetophenone was converted to 3-deoxygericudranin A in 5 steps via sequential protection, aldol condensation, Michael tvpe-cyclization, regioselective, C-benzylation and deprotection.

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InCl3-Catalyzed Regioselective Ring-Opening Reactions of Epoxides to β-Hydroxy Ethers

  • Kim, Byeong-Hyo;Piao, Fengyu;Lee, Eun-Joo;Kim, Ji-Sook;Jun, Young-Moo;Lee, Byung-Min
    • Bulletin of the Korean Chemical Society
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    • v.25 no.6
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    • pp.881-888
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    • 2004
  • By applying a catalytic amount of indium trichloride, regioselective ring-opening of epoxides to ${\beta}$-hydroxy ethers was established. While the alcoholysis of styrene oxides produed $S_N1$-type product, the alcoholysis of ${\alpha}$-heteroatom-substituted epoxides predominantly produced $S_N2$-type product.

An efficient Procedure for the Regioselective Synthesis of 10-Methoxy-11-Hydroxyaporphine from (R,S)-10,11-Dihydroxyaporphine

  • Kim, Jack C.
    • Archives of Pharmacal Research
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    • v.17 no.3
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    • pp.204-206
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    • 1994
  • A regioselective perparation of 10-methoxy-11-hydroxyaporphine ("Apocodeine, 1b") form (R, S)-10, 11-dihydroxyaporphine(apomorphine, 1a) is described. The isopropylidene ketal ring of 10, 11-(isopropylidenyldioxy) aporphine (2) obtained by the isopropylidenation of apomorphine, was regioselectively opened by the ten equivalent of timethylaluminum to give 100-hydroxy-11-t-butyloxyaporphine (3). The free 10-hydroxyl position of 3 was methylated with methyl p-toluenesulfonate/NaH, and afforded 10-methoxy-11-t-butyloxyaporphine (4) in high yield. Selective debutylation gave the desired 10-methoxy-11-hydroxyaporphine("apocodeine", 1b) in good yield.

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