• The Korean Journal of Pesticide Science
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• v.8 no.3
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• pp.168-174
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• 2004

In a course of the process for a lead optimization of 2-imino-l,3-thiazolines 1 which show a selective in vivo antifungal activity against rice blast, new compounds 2 in which C-5 was substituted by methyl group of the lead compound were synthesized and tested for the biological activity. Bromination of $\beta$-keto ester 7 followed by the reaction with thiourea and hydrolysis gave 2-imino-5-methyl-l,3-thiazoline carboxylic acid 3. Coupling reactions of 3 with aniline derivatives afforded 17 kinds of the corresponding 2-imino-5-methyl-l,3-thiazoline carboxanilides 2. Their in vivo antifungal activity against rice blast was weaker than that of 1, indicating that the in vivo antifungal activity of 2-imino-l,3-thiazolines was affected by the substituent at C-5. These results would be an important data for the molecular design in the lead optimization process of this series.

• Journal of Environmental Health Sciences
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• v.40 no.3
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• pp.215-224
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• 2014

Objective: This study was carried out in order to determine the depositional characteristics of pine needles, pine bark, and soil used as a passive air sampler (PAS) for atmospheric polybrominated diphenyl ethers (PBDEs). Methods: All three media were sampled from the same site. The PBDE concentrations were analyzed by HRGC/HRMS, and the lipid contents were measured using the gravimetric method by n-hexane extraction. Results: The total PBDE concentration was the highest in soil (22,274.57 pg/g dry), followed by pine bark (20,266.39 pg/g dry), and then pine needles (7,380.22 pg/g dry). Pine needles contained the highest lipid contents (21.31 mg/g dry), whereas soil (10.01 mg/g dry), and pine bark (4.85 mg/g dry) contained less. There were poor correlations between lipid content and total PBDE concentrations in the media ($R^2$=0.8216, p=0.2814). Congeners BDE 47, 99, 183, 196, 197, 206, 207 and 209 showed peak concentrations. Among these, BDE 206, 207, and 209 are highly brominated PBDEs that exist as particulates in ambient air. They accounted for 81.2% [69.2 (pine needles) - 89.0% (tree bark)] of the concentration and therefore are noted as the main congener of the total PBDEs. Conclusions: It can therefore be concluded that for reducing error by improper sampling, the same species of media should be recommended for use as a PAS for atmospheric PBDEs due to the differences in depositional characteristics.

• Journal of the Korean Chemical Society
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• v.41 no.2
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• pp.88-97
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• 1997

The silyltriflates$(Ph_{3-n}SiH(OTf)_n)$have been produced by the reaction of triphenylsilane and triflic acid$(CF_3SO_3H)$at low temperature. These highly reactive compounds are a valuable reagent for the synthesis of numerous new functional substituted silane derivatives. The reaction of silyltriflates with alkenyl- and alkynylmagnesium bromide as well as organolithium compounds gave new silanes$Ph_2SiHR(R=\;C(CPh,\;CH=CH_2,\;CH_2CH=CH_2,\; (CH_2)_2CH=CH_2,\;(CH_2)_3CH=CH_2)$in high yields. The hydrosilation of prepared alkenyl- and alkynylsilanesPh_2SiHR$in the presence of a platinum catalyst(Pt/C) at high temperature$(200{\circ}C)$gave carbosilane polymers$((Ph_2SiCH=CPh)_n$and$(Ph_2Si(CH_2)m)n;\;m=2∼4, n{\ge}10)$along with five- and six-membered silaalkane ring compounds derived from intramolecular hydrosilation reactions. All of the prepared compounds are confirmed by NMR, UV, IR and mass spectroscopy as well as elemental analysis.

• Journal of the Korean Chemical Society
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• v.23 no.1
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• pp.37-41
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• 1979

The kinetics of the reaction of benzyl m-nitrobenzenesulfonate with m-and p-substituted N,N-dimethylanilines in acetone have been investigated by an electric conductivity method. The effects of substituents on the reactivity of N,N-dimethylaniline and the existence of linear free energy relationship were discussed. The rate constants k were in the range 2.55∼487 $10^{-4}l{\cdot}mol^{-l}{\cdot}sec^{-1} (35^{\circ}C)$ and increased with the electron donating ability of substituents. In the present reaction, the Hammett plot was correlated with ${\sigma}$ substituent constant, especially using the new ${\sigma}$ value of 0.35 in p-MeO and it's ${\rho}$ value was found to be -1.37. r value for the reaction was very large than the value obtained in the reaction of benzyl bromide. $Br{\"{o}}nsted$ linear relationship was shown between rate constant and basicites except for p-MeO resulted from solvent effect. From the Bronsted plot, this reaction was suggested that the cleavage of the C${\cdot}{\cdot}{\cdot}$O bond in the $S_N2$ transition state proceed the bond formation.

• Korean Journal of Food Science and Technology
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• v.11 no.2
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• pp.77-80
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• 1979

Effects of interfering substances on the determination of L-ascorbic acid (AsA) in green tea and it's extracts by 2,4-dinitrophenylhydrazine (DNP) method was studied. and the removal of these interfering substances was also investigated. Under the condition prescribed for DNP method, AsA content of green tea are effected by some sugar, reductones, dicarbonyl compounds, organic acids, amino acids and others. All interfering substances except amino acids were eliminated by the chloroform extraction after adding o-phenylendiamine to sample solution. and remaining amino acids were eliminated almost completely by the treatment with ion exchange resin$(Amberlite{\;}IR-120H^{+})$. After removing the interfering substances by the above mentioned procedure, total AsA in green tea was determined by DNP method. The values obtained by this method were in good agreement with those by thin layer chromatography (TLC) method. and the method was more rapid and simple than TLC method.

• Membrane Journal
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• v.27 no.6
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• pp.528-535
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• 2017

In this study, halogen element was introduced into polyphenylene oxide polymer using bromination reaction, and then halogen element was replaced with imidazolium. Imidazolium corporated polyphenylene oxide polymer was synthesized and the synthesis was confirmed by various instrumental characterization. In addition, gas permeation properties of $O_2$, $N_2$, $CO_2$ were studied with different imidazolium contents. As the content of imidazolium increased, the ion exchange capacity increased and the mechanical strength decreased. The gas permeance showed a tendency to decrease slightly with increaing imidazolium contents. Whereas, it was confirmed that the tendency of $CO_2/N_2$ ideal selectivity increased as the imidazolium contents increased.

• Journal of Pharmaceutical Investigation
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• v.34 no.6
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• pp.513-519
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• 2004

A sensitive method for quantification of pinaverium bromide in human plasma was established using liquid chromatography-electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS). Glimepiride was used as internal standard. Pinaverium bromide and internal standard in plasma sample were extracted using tert-butylmethylether(TBME). A centrifuged upper layer was then evaporated and reconstituted with mobile phase of acetonitrile-5 mM ammonium formate (80/20, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS with multiple reaction monitoring (MRM) mode, pinaverium and glimepirde were detected without severe interference from human plasma matrix. Pinaverium produced a protonated precursor ion $([M+H]^+)$ at m/z 510.3 and a corresponding product ion at m/z 228.9. Internal standard produced a protonated precursor ion $([M+H]^+)$ at m/z 491.5 and a corresponding product ion at m/z 352.0. Detection of pinaverium bromide in human plasma was accurate and precise, with limit of quantitation at 0.5 ng/ml. The method has been successfully applied to bioavailability study of pinaverium bromide tablet in Korean healthy male volunteers. Pharmacokinetic parameters such as $AUC_t,\;C_{max},\;T_{max},\;K_{el}\;and\;t_{1/2}$ were calculated.

• Polymer(Korea)
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• v.24 no.3
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• pp.350-357
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• 2000

Curing behaviors of glass/epoxy prepreg for printed circuit boards (PCB) were studied by using dielectrometer and differential scanning calorimeter. This prepreg was showed the lowest ionic viscosity at about 115$^{\circ}C$, and then the ionic viscosity was gradully increased up to 15$0^{\circ}C$. This indicated that the curing reaction of this prepreg started at 115$^{\circ}C$ and the molecular weight was increased by the accelerated thermal cross-linking reaction. The loss factor and tan $\delta$ values were also measured and discussed. The dielectric behaviors of this prepreg system were also measured according to the cure cycle for PCB. This material was found to be thermally stable up to about 30$0^{\circ}C$ and then was showed an abrupt decomposition beyond this temperature.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.3
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• pp.212-218
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• 2001

This study was performed to estimate environmental and biological monitoring of workers exposed to methyl bromide through quarantine fumigation. Airborne methyl bromide and it's metabolites were analyzed by gas chromatography and ion chromatography, respectively. The results are as followings; airborne concentration of methyl bromide(TWA) was $2.08{\pm}1.56ppm$(N=8). Dispersion and setting/degas groups were $0.67{\pm}0.12ppm$(N=2) and $2.54{\pm}1.53ppm$(N=6), respectively. Bromide ion concentration in serum was $23.40{\pm}14.91mg/{\ell}$(N=10) in the exposed workers and $4.74{\pm}0.82mg/{\ell}$(N=21) in the non-exposed workers. Bromide ion concentration in urine was $35.56{\pm}26.89mg/{\ell}$(N=11) in exposed group and $6.62{\pm}2.31mg/{\ell}$(N=21) in non-exposed group. Good correlation was observed between concentration of serum and urine ($r^2$=0.890 p<0.01). No significant correlations of other determinants were observed. Calculated from a regressive curve, the biological half lifes of serum and urine were 10.7 and 5.9 days. In these results, biological monitoring of bromide ion of serum and urine provided useful information for evaluating exposure of workers to methyl bromide, so that an availability of bromide ion of biological samples was showed as biological monitoring indices for methyl bromide.

• Journal of Korea Society of Waste Management
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• v.35 no.8
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• pp.692-700
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• 2018

In this study, the results of PBDEs and HBCDs of the products and waste that contain BFRs such as domestic electronic products, automobiles and textile products were compared with international management standards, and their excess rates were calculated. Deca-BDE was detected among the PBDEs in TV rear cover plastics, car seats, automotive interior plastics, and automobile shredding residues of products and waste containing BFRs. The comparison with Basel Convention management standards (1,000 mg/kg) for PBDE-containing wastes (4 types in total) shows that the excess rate of all samples was less than 1.5%. The estimated excess rate compared to the EU and Basel convention management standards (1,000 mg/kg) for PBDEs (4 species + deca-BDE) and TV rear cover plastics was 37.5% (30 of 80 samples exceeded the standards). The estimated excess rate compared to the Basel convention management standards (1,000 mg/kg) for HBCD, building materials products and waste was 15.7% (17 of 108 samples exceeded the standards). In the case of PBDEs, it is necessary to remove only the rear cover of CRT TV among the electric and electronic products and treat it in the flame retardant treatment facility to improve the recycling collection system. In the case of HBCD, it is necessary to appropriately dispose of the recycled materials, heat insulation materials, TV plastics, and styrofoam in marine fishery among construction materials and restrict the use as recycled raw materials.