• Title/Summary/Keyword: 4-benzoquinone

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Ag Nanowires Prepared by a Modified Polyol Method with 1,4-Benzoquinone Additives

  • Kang, Miseon;Chung, Eunseon;Kim, Sang-Ho;Rhee, Seog Woo
    • Bulletin of the Korean Chemical Society
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    • v.35 no.11
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    • pp.3209-3212
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    • 2014
  • This paper describes a selective synthetic method of fabricating Ag nanowires by using a modified polyol process. To synthesize the Ag nanowire, an ethylene glycolic solution of silver nitrate and an ethylene glycolic solution of polyvinylpyrrolidone solution containing a small amount of organic oxidant, 1,4-benzoquinone, were slowly added to a hot ethylene glycol medium at $160^{\circ}C$ for 8 min using a syringe pump. The reaction mixtures were heated for an additional 45 min and cooled to room temperature. Finally, the silver nanomaterials were isolated from the mixture by centrifugation. The crystal structure of the nanomaterials was investigated by powder X-ray diffraction analyses, and their morphology was investigated by scanning electron microscopy. A small amount of organic oxidant, 1,4-benzoquinone, played a significant role in controlling the morphology during crystal growth. Consequently, Ag nanowires rather than Ag nanoparticles were selectively obtained.

Dehydrogenation of 9,10-Dialkyl-9,10-dihydroanthracene with 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (2,3-디클로로-5,6-디시아노-1,4-벤조퀴논을 利用한 9,10-디알킬-9,10-디히드로안트라센 化合物의 수소이탈 반응)

  • Wu-Lang Kim;Moo-Jin Jun
    • Journal of the Korean Chemical Society
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    • v.19 no.6
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    • pp.443-448
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    • 1975
  • A series of 9,10-dialkyl-9,10-dihydroanthracene has been dehydrogenated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in good yields. The yield decreased with the larger alkyl groups in this 9,10-dialkyl-9,10-DHA series(DHA=dihydroanthracene). It is conceivable that trans-9,10-diisopropyl-9,10-DHA was dehydrogenated more rapidly than the cis-isomer, and, bassed on this observation, a concerted mechanism was ruled out and an ionic mechanism is proposed.

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Microbiological Oxidation of Isophorone to 4-Hydroxyisophorone and Chemical Transformation of 4-Hydroxyisophorone to 2,3,5-Trimethyl-p-benzoquinone

  • Joe, Young-Ae;Goo, Yang-Mo;Lee, Youn-Young
    • Archives of Pharmacal Research
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    • v.12 no.2
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    • pp.73-78
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    • 1989
  • Oxidation of isophorone by various fungi was examined. Aspergillus niger oxidized isophorone to 4-hydroxyisophorone, 3-hydroxymethyl-5,5-dimethyl-2-cyclohexen-1-one and 5-hydroxymethyl-3,5-dimethyl-2-cyclohexen-1-one. 4-Oxoisophorone obtained by chromic acid oxidation of 4-hydroxyisophorone was transformed to 2,3,5-trimethyl-p-benzoquinone by acid treatment.

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MO Theoretical Studies on Stereoelectronic Control in the Addition Reaction of 1, 4-Benzoquinone-4-(O-methyloxime)$^*$

  • Ik-Choon Lee;Eun-Sook Han
    • Bulletin of the Korean Chemical Society
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    • v.4 no.1
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    • pp.41-44
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    • 1983
  • The chlorine addition and Diels-Alder cycloaddition of cyclopentadiene to 1, 4-benzoquinone-4-(O-methyloxime) have been studied MO theoretically. It has been shown that the reactions occur predominantly to the quinone ring double bond which is oriented anti to the nitrogen lone pair due to an n-${\sigma}^*$ interaction between the nitrogen lone pair, n, and the app. vicinal bond, causing the ${\pi}$ bond to be weakened and destabilized due to the less conjugation from reduced delocalization.

Immobilization of $\beta$-Galactosidase from E. coli K-12 CHS36 Using Tannin - Activated Cellulose Beads ($\beta$-Galactosidase의 Tannin 활성화 섬유소 입자에의 고정화)

  • Hong, Y.S.;Kwon, S.T.;Chun, M.J.;Sernetz, M.
    • Applied Biological Chemistry
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    • v.26 no.4
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    • pp.217-221
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    • 1983
  • $\beta$-Galactosidase($\beta$-D-galactoside galactohydrolase, E.C. 3. 2. 1. 23) from E. coli K-12 CSH 36 was immobilized on porous cellulose beads which were previously activated with tannin and p-benzoquinone. Their general properties and applicational possibities were investigated. The most effective, enzyme immobilization was obtained when tannin and p-benzoquinone, pH 11.0, were used together as activation reagents and a period of 6 hours of activation. The optimum pH of $\beta$-galactosidase was 5.5 for free enzyme and 6. 0 for the immobilized enzyme, the optimum temperatures for native and immobilized enzyme were both $50^{\circ}C$. Kms of native $\beta$-galactosidase and immobilized enzyme for ONPG(o-nitrophenyl galactopyranoside) were about $4.0{\times}10^(-4)M$ and $7.5{\times}10^(-4)M$, respectively. In the case of tannin : p-benzoquinone activated cellulose beads, the immobilized enzyme retained over 80% of the initial enzyme activity after 20 runs, which is very promising result far a possible industrial application.

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Production of 2-Methoxy-1,4-benzoquinone (2-MBQ) and 2,6-Dimethoxy-1,4-benzoquinone (2,6-DMBQ) from Wheat Germ Using Lactic Acid Bacteria and Yeast (젖산균 및 효모를 이용한 밀배아로부터 2-Methoxy-1,4-benzoquinone (2-MBQ) 및 2,6-Dimethoxy-1,4-benzoquinone(2,6-DMBQ)의 생산)

  • Yoo, Jong-Gil;Kim, Myoung-Dong
    • Food Engineering Progress
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    • v.14 no.4
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    • pp.292-298
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    • 2010
  • Wheat germ contains the glycosylated forms of 2-methoxy-p-benzoquinone (2-MBQ) and 2,6-dimethoxy-p-benzoquinone (2,6-DMBQ), both of which have antimicrobial and immunostimulatory effects. Conversion of glycosylated 2-MBQ and 2,6-DMBQ to their more functional unglycosylated forms requires enzymatic action of $\beta$-glucosidase. We investigated the applications of lactic acid bacteria and yeast that produce $\beta$-glucosidase as starters for production of unglycosylated 2-MBQ and 2,6-DMBQ from wheat germ. Lactobacillus zeae and Pichia pijperi were selected through $\beta$-glucosidase enzyme assays for 37 yeast strains and five strains of lactic acid bacteria. Lb. zeae was more efficient than P. pijperi at producing 2-MBQ and 2,6-DMBQ from wheat germ. After 48 hr of fermentation with a mixed culture of Lb. zeae and P. pijperi, the concentration of 2-MBQ was 0.46${\pm}$0.07 mg/g, indicating an approximately 1.6-fold higher concentration than that obtained by pure culture of Lb. zeae. However, the concentration of 2,6-DMBQ was not significantly enhanced by fermentation with a mixed culture of Lb. zeae and P. pijperi.

Fabrication of Poly(ethylene oxide)/Ag Nanoparticles/p-benzoquinone Composite Membrane Using AgNO3 Precursor for Olefin/Paraffin Separation (올레핀/파라핀 분리용 AgNO3 전구체를 활용한 poly(ethylene oxide)/Ag nanoparticles/p-benzoquinone 복합체 분리막 제조)

  • kim, Minsu;Kang, Sang Wook
    • Membrane Journal
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    • v.28 no.4
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    • pp.260-264
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    • 2018
  • Poly (ethylene oxide) (PEO)/Ag nanoparticles (AgNPs)(precursor : $AgBF_4$)/p-benzoquinone (p-BQ) composite membrane was prepared for olefin/paraffin separation. As a result, the performance of composite membrane was observed to be maintained at selectivity of 10 and permeance of 15 GPU up to 100 hours. The performance of the membrane was maintained for 100 hours was attributable to that Ag ions could be converted into stable Ag NPs by addition of p-BQ. Furthermore, the surface was partially polarized by the electron acceptor p-BQ, resulting in the formation of olefin carrier. In this study, since the cost of $AgBF_4$ used as a precursor of Ag NPs was relatively higher, $AgNO_3$ was utilized. As a result, it was confirmed that $AgNO_3$ couldn't show the stable formation of nanoparticle, resulting in the poor separation performance.

Mechanism of Action of Anticancer Drug Aziridinylbenzoquinones: Involvement of DT-diaphorase (DNA에 결합하는 항암제의 작용기전)

  • Lee, Chong-Soon-
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1994.11a
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    • pp.147-172
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    • 1994
  • Aziridinylbenzoquinones such as 3, 6-diaziridinyl-1, 4-benzoquinone (DZQ) and its 2, 5-methyl analog (MeDZQ) require bioreductive activation in order to elicit their anticancer activities. To determine the involvement of DTD in the activation of these drugs, we have used a ligation-mediated polymerase chain reaction to map the intracellular alkylation sites in a sing1e copy gene at the nucleotide level. We have performed this analysis in two human colon carcinoma cells, one proficient (HT-29) and one deficient (BE) in DT-diaphorase (DTD) activity. In the DTD proficient HT-29 cell line, DZQ and MeDZQ were found to alkylate both 5'-(A/T)G(C)-3' and 5'-(A/T)A-3' sequences. This is consistent with the nucleotide preferences observed when DZQ and MeDZQ are activated by purified DTD to reactive metabolites capable of alkylating DNA in vitro [Lee, C. -S., Hartley, J. A., Berardini, M. D., Butler, J., Siegel., D., Ross, D., & Gibson, N. W. (1992) Biochemistry, 31: 3019-3025]. Surprisingly in the DTD-deficient BE cell line a pattern of alkylation induced by DZQ and MeDZQ similar to that observed in the DTD-proficient HT-29 cells was observed. This suggests that reductive enzymes other than DTD can be involved in activating DZQ and MeDZQ to DNA reactive species in vivo.

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Molecular Switching Coordination Polymers. 4.4'-Chalcogenobispyridine Bridged Cobalt Benzoquinone Complexes

  • 조두환;정종화;여환진;손윤수;정옥상
    • Bulletin of the Korean Chemical Society
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    • v.16 no.6
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    • pp.504-507
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    • 1995
  • The reaction of Co2(CO)8 with 3,6-di-tert-butyl-1,2-benzoquinone in the presence of the respective 4,4'-chalcogenobispyridine results in the coordination polymers of [CoⅢ(4,4'-X(Py)2)(DBSQ)(DBCat)]n (X=S, Se, Te; Py=pyridine; DBSQ=3,6-di-tert-butylsemiquinone; DBCat=3,6-di-tert-butylcatechol). The title compounds undergo an intramolecular Cat → Co electron transfer, and thus change toward the [CoⅡ(4,4'-X(Py)2)(DBSQ)2]n at elevated temperature. The temperature-switching properties of the compounds directly depend upon the electronegativity of the chalcogen atom of the 4,4'-chalcogenobispyridine coligands. The spectroscopic data disclose that the properties of [CoⅢ(4,4'-S(Py)2)(DBSQ)(DBCat)]n and [CoⅢ(4,4'-Se(Py)2)(DBSQ)(DBCat)]n are similar each other in contrast to those of [CoⅢ(4,4'-Te(Py)2)(DBSQ)(DBCat)]n.