• Proceedings of the Korean Society of Applied Pharmacology
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• 2001.11a
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• pp.80-80
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• 2001

The roots of Scutellaria baicalensis Georgi have been used in the chinese medicine for the treatment of inflammation, fever and headache. Recent studies had shown that baicalin and baicalein showed a detoxifying effect and could inhibit peripheral capillary permeability, and Wogonin was found to inhibit the proliferation of tumor cells. Wogonin has been synthesized as shown in schem. Compound 2 was prepared from 2,6-dimethoxy-1,4-benzoquinone(1) followed by acylation to give compound 3. The base treatment of 3 gave cyclized product which was carried by deprotection of methyl group chemoselectively. Overall step included relatively simple ten steps.

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.416-421
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• 1986

The solvent coordination effect on the excited state processes of Mg(II)- and Zn(II)-phthalocyanines has been described. The triplet state of these compounds decays with mixed first and second order kinetics or mainly second order kinetics depending on the solvents used. The first order component of the rate constants decrease along with the series, dimethylsulfoxide (5-coordinated), 1-chloronaphthalene (4-coordinated) and piperidine (6-coordinated), while the second order rate constant is dependent on the diffusion rate constant of the solvents. The excited state quenching by methylviologen or p-benzoquinone is discussed. And ion recombination rate constant is given.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.814-822
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• 1993

To improve the solubility and adhesion strength of diamine-quinone polymers, urethane group was introduced into the polymer backbone. Urethane group containing polymeric diamines(UDA) were prepared firstly by the decarboxylation of the NCO group in NCO terminated prepolymer obtained from the reaction of MDI and 1.6-hexandiol. The reaction mole ratio of NCO/OH was changed from 1.2 to 2.1 to increase the molecular weight of diamine. From the addition reaction of UDA and p-benzoquinone in THF or DMSO solvent, five kinds of urethane group containing diamine/quinone polymers(PUAQ) were prepared according to the diamine used. IR, NMR, UV-visible spectroscopy and GPC were used to characterize the molecular structure and molecular weight of UDAs and PUAQs. Thermal analysis of polymer by DSC and TGA were carried out according to the molecular weight differency. Also solubility test of UDA and PUAQ with 10 different solvents were carried out to predict the coacting property of the polymers.

• BMB Reports
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• v.36 no.5
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• pp.442-449
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• 2003

NAD(P)H quinone oxidoreductase is a ubiquitous enzyme that is known to directly reduce quinone substrates to hydroquinones by a two-electron reaction. We report the identification of NADPH quinone oxidoreductase from Kluyveromyces marxianus (KmQOR), which reduces quinone substrates directly to hydroquinones. The KmQOR gene was sequenced, expressed in Escherichia coli, purified, and characterized. The open-reading frame of the KmQOR gene consists of 1143 nucleotides, encoding a 380 amino acid polypeptide. The nucleotide sequence of the KmQOR gene was assigned to EMBL under accession number AY040868. The $M_r$ that was determined by SDS-PAGE for the protein subunit was about 42 kDa, and the molecular mass of the native KmQOR was 84 kDa, as determined by column calibration, indicating that the native protein is a homodimer. The KmQOR protein efficiently reduced 1,4-benzoquinone, whereas no activities were found for menadiones and methoxyquinones. These observations, and the result of an extended sequence analysis of known NADPH quinone oxidoreductase, suggest that KmQOR possesses a different action mechanism.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.2
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• pp.41-45
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• 2013

Extractives of garlic (Allium scorodorpasum) and green pepper (Capsicum annuum L.) were used to prevent and exterminate rice weevils which contaminate stored rice. The extractives exhibited great efficacy against Sitophilus oryzae and Tribolium castaneum by annihilating all the weevils contained in a bottle. Furthermore, kraft paper coated by 5% extractives also displayed good effectiveness against the rice weevils. When rice weevils were stored with rice in a sack made of extractives-coated kraft paper, the number of living insects was sharply decreased according to elapsed time. In particular, 1,4-benzoquinone, which is very harmful to human, was detected from rice contaminated by Sitophilus oryzae and Tribolium castaneum through the analysis of GC/MS.

• Journal of Photoscience
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• v.12 no.2
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• pp.109-111
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• 2005

It was found that 1,4-diketones such as 1,4-diphenyl-l,4-butanediones containing N,N-dimethylaminophenyl (pDPB) and N,N-dimethylaminonaphthyl (nDPB) at C2 are converted into 3-(4-dimethylaminoaryl)-1-phenylpropan-lones (pPPA and nPPA) by treatment with $Ca(OH)_2$ in methanol, which was easily oxidized to enone, i.e., 3-(4-dimethylaminophenyl)-l-phenylpropenones (pPPE and nPPE), when treated with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) in dichloromethane.

• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.95-99
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• 1990

The dioxygen transfer reaction from $N^5$-ethyl-4a-hydroperoxy-3-methyllumiflavin anion (4a-FlEtOO-) has been extended to isomeric aminophenol systems (1a-4a). O-aminophenol (o-AP, 1a & 2a) and p-aminophenol(p-AP, 3a & 4a) were turned out to be good substrates, whereas m-aminophenol(m-AP, 5a) was not. This is due to the charge location which is not on the carbon bearing the amino group. o-AO's react with 4a-FlEtOO- to give isophenoxazine derivatives (6 & 7) and with p-AP's to produce p-benzoquinone derivatives (8 & 9). The partition coefficients $(k_2/k_3)$ of 1a & 2a were $4.84{\times}10^{-4}\;&\;1.66{\times}10^{-5}M$, respectively and those of methylated aminophenolates, 2a & 4a were 4-10 times greater than nonmethylated substrates, 1a & 3a.

• Textile Coloration and Finishing
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• v.26 no.4
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• pp.277-282
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• 2014

Two tert-butyl substituted phthalocyanines(Pcs), in metal-free and metallated forms, were synthesized and the fluorescence responses toward various nitro derivatives, including picric acid(PA), 2,4-dinitrotoluene(DNT), 1,4-dinitrobenzene(DNB), 4-nitrotoluene(NT), nitrobenzene(NB), 1,4-benzoquinone(BQ), and nitromethane(NM) were investigated. Among the various nitro derivatives, current Pc derivatives exhibited efficient and exclusive fluorescence quenching in the presence of picric acid, which was readily observed by a naked eye. Quenching efficiency was estimated by the Stern-Volmer relationship, in which quenching constant, KSV, was calculated to be in the range of $10^4M^{-1}$. It was also found out that the aggregational behaviors of these Pcs are heavily dependent on the nature of solvent systems, subsequently affecting the quenching efficiency.

• Analytical Science and Technology
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• v.8 no.3
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• pp.249-258
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• 1995

The polymers, polyazine, polyazomethine ( I ) and polyazomethine ( II ) were prepared by the condensation of p-benzoquinone with hydrazine hydrate, p-phenylenediamine and diaminomaleonitrile in DMSO, respectively. The IR spectra of these polymers showed a characteristic peak of schiff base (-C=N-) at about $1600cm^{-1}$. These polymers dissolved in concentrated sulfuric acid showed UV/VIS absorption near 300nm indicatiog the presence of iminium ion(>$C\limits^{\small\oplus}=NH-$). Another UV/VIS absorption band in the region of 350~415nm was shown presumably due to the charge transfer transition in the molecule. The electrical conductivities of polyazine, polyazomethine ( I ) and ( II ) were measured. The self-electrical conductivity of these was found to be about $10^{-14}{\sim}10^{-11}{\Omega}^{-1}cm^{-1}$ and these polymers doped with $I_2$ showed the maximum conductivity of about $10^{-2}{\Omega}^{-1}cm^{-1}$.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.335-342
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• 1991

The effect of pressure and temperature on the stabilities of the charge transfer complexes of 1,3,5-trinitrobenzene, tetrachloro-p-benzoquinone and tetracyanoethylene with hexamethylbenzene in carbon tetrachloride has been investigated by spectrophotometric measurements. The equilibrium constants for the formation of the complexes were obtained at various temperature and pressure, and thermodynamic parameters for the formation of the charge transfer complexes are calculated from these values. The relative stabilities of charge transfer complexes with hexamethylbenzene increase in the order; 1,3,5-trinitrobenzene < tetrachloro-p-benzoquinone < tetracyanoethylene. This may be regarded as an order of relative acidity of these compounds in complexation with hexamethylbenzene and is explained in terms of the negative inductive effect of the ${\pi}$ acceptors. The red-shift at higher pressure, the blue-shift at higher temperature and the relation between pressure and oscillator strength are discussed on the basis of thermodynamic functions.