• Journal of the Korean Magnetic Resonance Society
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• v.22 no.4
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• pp.115-118
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• 2018

Dipyrromethane 2 functionalized with 3-chloropropyl group on the meso carbon undergoes an unusual intramolecular electrophilic aromatic substitution reaction in the presence of $NaN_3$ instead of a simple nucleophilic substitution reaction. As a result, a new chiral dipyrromethane 1 was synthesized. In this reaction, the ${\beta}$-carbon of the pyrrole ring functions as a nucleophile while the carbon next to the chlorine atom acts as an electrophile. Interestingly, this reaction progresses even in the absence of an acid catalyst. Compound 1 was fully characterized by $^1H-^1H$ and $^1H-^{13}C$ COSY NMR spectroscopic analyses and the high resolution EI mass spectrometry.

• Bulletin of the Korean Chemical Society
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• v.3 no.4
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• pp.157-162
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• 1982

9-Methylenethioxanthene(6) was synthesized and for the first time good mp and spectral data were taken. Reaction of (6) with thioxanthylium ion (1) in acetonitrile led to a carbenium addition adduct (8) which then was either attacked by a variety of nucleophiles subsequently added or underwent deprotonation reaction to give an olefin (13). From these reactions, was obtained bis-9,9'-thioxanthenylmethane (2). These results indicate clearly that (2) can be formed via (8) by accepting hydride. Isolation of (2) and (6) from the reaction of (1) with 9-methylthioxanthylium ion (18) also supports the involvement of (8) in the reaction of (1) with dimethylmercury. However, addition of thioxanthene radical (4) to (6) has not been ruled out.

• Elastomers and Composites
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• v.28 no.3
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• pp.191-197
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• 1993

The graft copolymerization of methyl methacrylate(MMA) onto natural rubber latex(NRL) initiated by t-butyl hydroperoxide(t-BHPO) was investigated in aquous medium. The grafting percentage, grafting efficiency and total conversion were observed in various reaction conditions such as monomer, initiator and emulsifier concentration, reaction temperature, reaction time and agitation speed. The optimum conditions for the graft copolymerization onto natural rubber latex were as follows ; At given monomer concentration of $3{\times}10^{-2}mole/l$, the maximum grafting percentage was appeared in the case of grading in initiator concentration of $4{\times}10^{-2}mo1e/l$ and emulsifier concentration of 0.2wt.% at $40^{\circ}C$ for 5hrs.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.500-503
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• 1989

Synthetic studies have been carried out for the addition or substitution of phosphorus nucleophiles to the cation $[(exo-6-R-{\eta}^ {5_-}2-MeO-C_6H_5)Mn(CO)_2NO]PF_6,$ 2. $PPh_3$ reacts with 2 to yield the CO displaced product and $MePPh_2$ attacks the dienyl ring of 2 to yield the phosphonium adduct or the metal to give the CO displaced depending upon the reaction temperatures. Nucleophilic addition of HPPh2 to the dienyl ring of 2 gives a neutral substituted product. $P(OMe)_3$ reacts with 2 to yield a mixture of ring adduct and CO displaced product at room temperature. $At - 20^{\circ}C,\;P(OMe)_3$ attacks the dienyl ring of 2 to give a posphonium adduct, which underwent Arbuzov reaction. This reaction affords a new route to the phosphonate complexes.

• Archives of Pharmacal Research
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• v.22 no.3
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• pp.255-261
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• 1999

The effect of biphenyl dimethyl dicarboxylate (PMC) on the cellular and nonspecific immunosuppressions by ketoconazole (KCZ) was investigated in ICR mice. PMC at a dose of 6 mg/kg was administered orally to mice daily for 14 consecutive days. KCZ was suspended in RPMI 1640 medium and orally administered at 160 mg/kg/day 2 hrs after the administration of PMC. Immune responses of the delayed-type hypersensitively (DTH) reaction to sheep red blood cells (SRBC), phagocytic activity and natural killer (NK) cell activity were evaluated. DTH reaction to SRBC was enhanced to normal level by the combination of PMC and KCZ, as compared with treatment of KCZ alone. In the combination of PMC and KCZ, as compared with treatment of KCZ alone, there were also significant increases in activities of natural killer (NK) cells and phagocytes along with circulating leukocytes. These findings indicate that PMC shows a significant restoration from the immunotoixc status induced by KCZ.

• Archives of Pharmacal Research
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• v.12 no.4
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• pp.259-262
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• 1989

The reaction of the sodium salts of 4-methoxy and 4, 7-dimethoxy 6-hydroxy benzofuran-5-carboxylic acid with ethyl chloroformate yields the corresponding dicarbethoxy derivatives. The N-substituted amides were obtained by treating the latter compounds with amines. The corresponding hydrazides were synthesized by the reaction of hydrazine hydrate on the dicarbethoxy derivatives which spontaneously cyclized to 5-substituted-2, 3- dihydro-1, 3, 4, -oxadiazol-2-one. Also the reaction with phenyl hydrazine has been studied. The dicarbethoxy derivatives and N-substituted amides were tested against Gram positive and Gram negative bacteria in vitro. Most of the compounds posses moderate or slight activity against Gram positive bacteria.

• Korean Journal of Crystallography
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• v.16 no.2
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• pp.66-74
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• 2005

Marine natural products with various bioactivities are featured with similar structure to the common secondary metabolites and generally modified by halogenides, such as chloride, bromide, and iodide ions. Vanadium haloperoxidase is a key enzyme for the production of marine natural products and a metalloenzyme which requires a cofactor of vanadate. This review will cover isolation of vanadium haloperoxidase and the protein structures, as well as reaction mechanism of the metalloenzyme. Finally, reactivity of vanadium haloperoxidase and the biosynthesis of the secondary metabolites of indole, terpenoids, and acetogenins will be described.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2968-2972
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• 2013

A highly efficient and environmentally benign protocol has been developed for the first time to produce a wide range of biologically active 5-hydroxyindole derivatives using montmorillonite KSF clay as a reusable solid acid catalyst. The use of recyclable clay makes this procedure quite simple, more convenient and cost-effective.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3848-3851
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• 2010

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.888-888
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• 2009

A simulation study on SCR (Steam Carbon dioxide Reforming) process in gas-to-liquid (natural gas to Fischer-Tropsch synthetic fuel) process was carried out in order to find optimum reaction conditions for GTL (gas-to-liquid) process reaction. Optimum SCR operating conditions for synthesis gas to FT (Fischer-Tropsch) process were determined by changing reaction variables such as feed temperature and pressure. During the simulation, overall synthesis process was assumed to proceed under steady-state conditions. It was also assumed that physical properties of reaction medium were governed by RKS (Redlich-Kwong-Soave) equation. SCR process was considered as reaction models for synthesis gas in GTL proess. The effect of temperature and pressure on SCR process $H_2$/CO ratio and the effect of reaction pressure on SCR reaction were mainly examined. Simulation results were also compared to experimental results to confirm the reliability of simulation model. Simulation results were reasonably well matched with experimental results.