• Journal of the Korean Chemical Society
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• v.46 no.5
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• pp.479-485
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• 2002

• Applied Biological Chemistry
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• v.37 no.3
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• pp.210-215
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• 1994

${\underline{O}},{\underline{O}}-Diethyl-{\underline{S}}-phenyl\;phosphorothiolate-^{18}O$ and other related compounds were prepared and oxidized with m-chloroperbenzoic acid (MCPBA). Each reaction was followed by $^{31}P$ NMR and the products were analyzed by GC-MS. ${\underline{O}},{\underline{O}}-Diethyl-{\underline{S}}-phenyl\;phosphorothiolate-^{18}O$ was converted to diethyl methyl phosphate in methanol by MCPBA and it was confirmed to contain $^{18}O$, which proved that the originally proposed mechanism of Segall and Casida operates in the oxidative reaction.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.392-397
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• 2007

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.185-190
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• 2005

Solid phase synthesis of 16, which is a derivative of the first systemic fungicide, carboxin 1 was described. Reaction of 1,3-oxathiolane derivative with solid resin of 4-hydroxy-3-nitrobenzophenone 6 gave 9 in 82% yield. Oxidation of sulfur in the solid 1,3-oxathiolane 9 by MCPBA followed by a ring expansion reaction under the acid catalyst afforded the corresponding dihydro-1,4-oxathiin derivative 12. Treatment of the solid 1,3-oxathiolane 9 with p-methoxyaniline resulted in 1,3-oxathiolane 14, 1,3-oxathiolane sulfoxide 15, dihydro-1,4-oxathiin 16, and acetoacetanilide derivative 17 in 41%, 35%, 14%, 10% yields, respectively.

• Applied Biological Chemistry
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• v.39 no.3
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• pp.227-234
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• 1996

4-Methyl-2,6,7-trioxa-1-phosphabicyclo [2,2,2] octane 1-sulfide (BPS), 4-Methyl-2,6,7-trioxa-1-phosphabicyclo[2,2,2] octane 1-oxide (BPO) and related monocyclic methylphosphates were prepared and the oxidation of BPS with MCPBA in chlorofrom or methanol was carried out to investigate the formation of reactive intermediates and reaction mechanism. BPO was the only product in chloroform while in methanol isomeric monocyclic methylphosphates were formed through opening of bicylic structure with subsequent phosphorylation of methanol by reactive intermediate formed in reaction. Formation of little amount of BPO was also observed. The structure of phosphorylating intermediate was probed with various spectroscopic methods and monocyclic methyl sulfenyl ester was suggested as a possible structure.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.169-175
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• 1993

O-Ethyl S-methyl ethylphosphonothioate was studied for chemical and metabolic oxidation using $^{31}P-NMR$ analyses. The chemical shifts of O-ethyl ethylphosphonic acid (2) which is one of major metabolites were changed with the variation of oxidation systems. $^{31}P-NMR$ chemical shifts of 2 were observed at 40.15ppm from oxidaton by MCPBA, 30.98 ppm by MMPP, 29.31 ppm from in vitro rat liver microsomal oxidation, and 29.10 ppm from in vivo metabolism in houseflies. $^{31}P-NMR$ chemical shift of 2 in two different solvents such as deutero-chloroform and deuterium oxide were observed at 30.70 ppm and 40.15 ppm, respectively. And those of the metabolites were also observed at around 30 ppm under the conditions of pH 3, 5.6 and 14 and 47.91 ppm under pH 1 which is a strong acidic condition. It could be explained that the ionized form of 2 should have greater shielding effect on phosphorus atom and hence shows upfield chemical shift in polar solvents and alkaline conditions. On the other hand, a protonated form under organic solvents and the strong acidic condition should have less shielding effect than its ionized form, shifting the peak downfield.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.10-15
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• 1998

The bimolecular inhibition rate constants of carbofuran and N-dimethylphosphinothioyl carbofuran(PSC) to acetylcholinesterase(AChE) were $7.7{\times}10^{5}\;M^{-1}{\cdot}min^{-1}$ and $1.2{\times}10^{3}\;M^{-1}{\cdot}min^{-1}$, respectively. These results showed that PSC required a bioactivation process for its toxic action because it didn't inhibit the target enzyme effectively. The potency of PSC as an inhibitor of AChE increased when PSC and AChE were incubated with microsomes fortified with NADPH compared with microsome alone. Piperonyl butoxide(PBO) addition to these coupled systems greatly reduced the inhibition of the target enzyme by blocking the bioactivation process. In vivo inhibition study of mouse brain AChE, $I_{50}$ value for AChE was 28 mg/kg for PSC and the value increased to 57 mg/kg when PBO was pretreated. This result showed that cytochrome $P_{450}$ would also play a role in the bioactivation process of PSC in vivo. And conversioin of carbofuran from PSC was 55 % in a chemical oxidation system using meta-chloroperoxybenzoic acid. The oxidative activation of PSC to carbofuran was shown to be essential for showing its toxicological action and cytochrome $P_{450}$ was identified as an important enzyme which participated in this process.