• Journal of the Korean Chemical Society
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• v.13 no.3
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• pp.221-228
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• 1969

The nucleophilic addition rate constants of n-amyl-, n-hexyl-, n-octyl-and n-decyl mercaptide ion to 3,4-methylenedioxy-${\beta}$-nitrostyrene were determined and found to be 2.82 ${\times}10^8$ $M^{-2} .sec^{-1}$, 1.00 ${\times}10^8$ $M^{-2}.sec^{-1}$, 2.23 ${\times}10^8$ $M^{-2} .sec^{-1}$ and 1.77 ${\times}10^8$ $M^{-2}.sec^{-1}$ respectively. At low pH, for n-amyl-, n-hexyl-, n-octyl-and n-decyl mercaptan the values determined are 2.82 ${\times}10^{-2}$ $M^{-1} . sec^{-1}$, 1.95 ${\times}10^{-2}$ $M^{-1} . sec^{-1}$, 7.08 ${\times}10^{-2}$ $M^{-1} . sec^{-1}$ and 5.63 ${\times}10^{-2}$ $M^{-1} . sec^{-1}$ respectively. The rate equations which can fully explain the addition mechanism over wide pH range were also be obtained.

• Journal of the Korean Applied Science and Technology
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• v.8 no.1
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• pp.21-26
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• 1991

The rate constants for the addition reaction of thiourea to nitrone derivatives were determind at various pH and reaction rate equation which could be applied over a wide pH were obtained. The substituent effects and general base catalysis for the addition of thiourea to nitrone derivatives were observed. On the basis of these findings, a plausible reaction mechanism for the nucleophilic addition of thiourea to nitrone was proposed.

• Bulletin of the Korean Chemical Society
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• v.20 no.6
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• pp.712-714
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• 1999

The rate constants for the nucleophilic addition of potassium cyanide to α,N-diphenylnitrone and its derivatives (p-OCH3, p-CH3, p-Cl, and p-NO2) were determined by ultraviolet spectrophotometer at 25℃, and the rate equations which can be applied over a wide pH range were obtained. On the basis of pH-rate profile, adduct analysis, general base catalysis and substituent effect, a plausible mechanism of this addition reaction was proposed: At high pH, the cyanide ion to carbon-nitrogen double bond was rate controlling, however, in acidic media, the reaction proceeded by the addition of hydrogen cyanide molecule to carbon-nitrogen double bond after protonation at oxygen of a,N-diphenylnitrone. In the range of neutral pH, these two reactions occured competitively.

• Archives of Pharmacal Research
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• v.17 no.1
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• pp.39-41
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• 1994

Various N,N'-disubstituted ureas 5 were easily prepared from the corresponding primary amide 1 by tratment with N-Bromophthalimide $(NBP)-AgOAc-RNH$_{2}$ 4 in dry N,N-dimrthylformamide (DMF). This reaction envolved the intemediate formation of isocyanate 3 from amide 1 via Hofmann rearrangement by treatment with AgOAc and NBP and nucleophilic addition of amine 4 to this isocyante 3. This method is simple enough to be applied to the synthesis of various N,N'-disubstututed ureas scale conviently.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.685-688
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• 2007

• Nuclear Engineering and Technology
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• v.7 no.4
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• pp.311-316
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• 1975

Kinetic studies on the halide exchange reactions of substituted benzoyl chlorides have been carried out. The experimental result has been explained reasonably in terms of HSAB principle and EH-Theory, and addition elimination mechanism has been proposed for this type of reaction.

• Bulletin of the Korean Chemical Society
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• v.7 no.1
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• pp.23-25
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• 1986

Reaction of ${\alpha}-cyano-{\beta}-phenylacrylic$ acid derivatives (Ⅰ) with thioglycolic acid in the molar ratio of 1:2 in saturated sodium bicarbonate solution yielded 3-(4'-oxo-2'-thiazolin-2'-yl)-2-phenyl-4-oxotetrahydrothiophene derivatives (V). Thioglycolic acid was found to be added not only to carbon-carbon double bond but also to carbon-nitrogen triple bond and those adducts were cyclized to V.

• Bulletin of the Korean Chemical Society
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• v.7 no.1
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• pp.25-29
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• 1986

The reaction of cysteine with cinnamaldehyde have been studied kinetically and thermodynamically. It was found that the reaction proceeds in two steps; formation of the monoadduct by a Michael type addition followed by the nucleophilic attack of the second cysteine to the carbonyl carbon of the monoadduct to afford the thiazolidine derivative. A reaction profile for the reaction of cysteine with cinnamaldehyde was constructed based on the thermodynamic parameters analyzed for the forward and the reverse reactions. It was assumed that the second step of this reaction accompanies an intermediate, a Schiff base.

• Environmental Mutagens and Carcinogens
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• v.17 no.2
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• pp.97-108
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• 1997

The drugs or xenobiotics introduced to the body, are detoxified through the process of biotransformation in the body. In this process, most of the insoluble compounds become more polar, soluble and easily excretable. But, parts of introduced materials are metabolized to highly reactive electrophilic carcinogens through activation pathways. These metabolites are toxic and can react with DNA, RNA and proteins which are nucleophilic compounds. The objective of this study is to illustrate the aleactivation pathways of two highly reactive epoxide compounds, vinyl carbamate epoxide (VCO) and 2'-(4-nitrophenoxy)oxirane (NPO). They are the ultimate electrophilic carcinogens of ethyl carbamate(urethane) and 4-nitrophenyl vinyl ether, respectively. In this research, we studied the inhibition of the mutagenic activities of VCO or NPO by nuchieophiles [glutahione(GSH) and N-acetylcysteine(NAC)], detoxifying enzymes[epoxide hydrolase and glutathione-S-transferase(GST)] and intracellular organelles (microsomes and cytosol). In addition we also tested the suppression of DNA adducts formation by GSH and NAC. The results are summerized as follow. 1. The microsomes and cytosol which contain epoxide hydrolase and GST, respectively, decreased the mutagenicity of VCO (74% and 95%, respecfivel), and NPO (35% and 93%, respectively). The nucleophilic GSH and NAC decreased the mutagenicity by 86% (VCO) and 80% (NPO), 76% (VCO) and 40% (NPO), respectively. 2. The purified epoxide hydrolase decreased the mutagenicity of two epoxides in a dose-dependent manner, and GSH also decreased the mutagenicity in the presence of GST. 3. Formation of two DNA adducts, 7-(2'-oxoethyi)guanine (OEG) and N2,3-ethenoguanine(EG), were compared in the presence of calf thymus DNA and epoxide (VCO or NPO) in vitro system. The amounts of DNA adducts were decreased in the presence of GSH (25% and 29% in VCO, 32% and 29% in NPO), and NAC (14% and 16% in VCO, 21% and 11% in NPO), respectively. From these results, it is concluded that the ultimate carcinogenic metabolites, VCO and NPO, can be made in the body, but much of them may be inactivated and detoxified by the nucleophilic GSH, NAC and detoxifying enzymes (epoxide hydrolase and GST). Therefore, by these mechanism, the formation of DNA adducts and mutagenic activities of these two epoxides may be lowered in vivo.

• Bulletin of the Korean Chemical Society
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• v.9 no.3
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• pp.115-117
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• 1988

The addition of L-cysteine without blocking amino and carboxyl groups to${\beta},{\beta}$-dinitrostyrene derivatives(11a-e) were investigated. ${\beta},{\beta}$ -Dinitrostyrene derivatives(11a-e) easily undergo addition reactions with L-cysteine to from s-(2,2-dinitro-1-phenylethyl)-L-cysteine(12a), s-[2,2-dinitro-1-(p-methyl)phenylethyl]-L-cysteine (12b), s-[2,2-dinitro-1-(p-methoxy)phenylethyl]-L-cystein e(12c), s-[2,2-dinitro-1-(p-chloro)phenylethyl]-L-cysteine (12d) and s-[2,2-dinitro-1-(p-nitro)phenylethyl]-L-cysteine( 12a), respectively. The structure of adducts were confirmed by means of spectral data, molecular weight measurement and elemental analysis.