• Journal of the Korean Chemical Society
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• v.37 no.12
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• pp.1060-1067
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• 1993

A series of New N-[1-(benzotriazol-1-yl)-X-substituted benzyl]-Y-substituted aniline derivaties (S) have been synthesized. And the rate of hydrolysis was investigated kinetically in 25% (v/v) aqueous methanol at 25$^{\circ}C$. On the basis of rate equations, solvent effect $m {\ll} 1,\; n \leq 3\; and\; m {\ll} l$), salt effect, general base catalysis, substituent effect (${\rho}_{xy}$ > > 0), and hydrolysis products analysis, it may be concluded that the hydrolysis of N-[1-(benzotriazol-1-yl)benzyl]aniline proceeds the "A-$S_N2$" mechanism below pH 12.0, while above pH 13.0, the hydrolysis proceeds through a typical "$S_N2$" mechanism.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.29-36
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• 1999

A series of N-phenyl-O-phenylthionocarbamate derivatives were synthesized and determinated fungicidal activities in vitro against gray mold (Botrytis cinerea) and capsicum phytophthora blight (Phytophthora capsici) which showed resistance and sensitivity to benomyl and metalaxyl as systemic fungicides, respectively. The structure-activity relationship (SAR) was investigated by Free-Wilson analysis method and Hansch method. From the basis on the findings, the N-phenyl(X) groups had more contributions than O-phenyl(Y) groups did and ortho-substituents on the N-phenyl group showed high fungicidal activities. Especially, 4-cyano substituent, 2 as X-group showed 50% inhibition($pI_{50}=5.50$) of hyphae growth at 0.8ppm against resistance P. capsici (RPC) And hydroxyl substituents, 12 and 23 displayed the highest fungicidal activity against resistant B. cinerea (RBC), sensitive B. cinerea (SBC), and sensitive P. capsici (SPC). Antifungal activities of SPC were dependent upon molar refractivity (MR) constant and those of others relied on hydrophobic parameters (${\sigma}$ and logP). For increasing fungicidal activity against RPC and SBC, the optimum values of the sigma (${\sigma}$) and field(F) constants as electron withdrawing groups were 0.32 and 0.18, respectively.

• Journal of the Korean Chemical Society
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• v.25 no.6
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• pp.376-382
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• 1981

The rates and the activation parameters for the reaction of phenacyl bromide with substituted anilines in methanol and dimethylformamide were measured. The effects of substituted anilines were discussed. The rate of the reaction was increased with the electron donating power of substituent and showed larger value in DMF than in MeOH. The isokinetic relationship was shown between ${\delta}H^{\neq}$ and ${\delta}S^{\neq}$, isokinetic temperature was 539 and $400^{\circ}C$ in MeOH and DMF respectively, but p-nitro aniline was deviated from linearity in both solvents caused by solvent effects. The excellent linear relationship between log k and p$K_a$ of substituted anilines was observed by following equation. log k = 0.57p$K_a$-1.28 (r = 0.996) in MeOH at $45^{\circ}C$, log k = 0.65p$K_a$-0.88 (r = 0.970) in DMF at $45^{\circ}C$. From the Hammett plot, this reaction was a nucleophilic displacement of aniline to phenacyl bromide and the following equation was obtained at $45^{\circ}C$. log k/$k_0$ = -2.00${\sigma}$ + 0.06 (r = 0.985) in MeOH; log k/$k_0$ = -2.22${\sigma}$ + 0.08 (r = 0.995) in DMF. Large deviation of p-nitro aniline in DMF is resulted from solvent effects too. From above results, the substituent effect of this reaction can be described as $S_N2$ mechanism and bond formation more proceeds in DMF relative to MeOH.

• Journal of the Korean Chemical Society
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• v.40 no.2
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• pp.128-134
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• 1996

The kinetics of the hydrolysis of dihydro-1, 4-oxathiin derivatives were investigated by ultraviolet spectrophotometry in H2O at $25^{\circ}C.$ A rate equation which can be applied over a wide pH range was obtained. The substituent effects on the hydrolysis of dihydro-1, 4-oxathiin derivatives were studied and the rate of hydrolysis was shown to be accelerated by electron accepting groups. Final product of the hydrolysis was 2-(2-hydroxyethylthio)acetoacet-anilide enol form. On the basis of rate equations derived and judging from hydrolysis products obtained and from general base effect and substituent effects, plausible mechanism of the hydrolysis in various pH range have been proposed. Below pH 3.5, the hydrolysis was initiated by the protonation and followed by the addition of water to 2-carbon. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxide to 2-carbon. In the range of pH 4.0∼10.0, the addition of water to dihydro-1,4-oxathiin is rate controlling step.

• Korean journal of applied entomology
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• v.24 no.4 s.65
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• pp.231-238
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• 1986

Molecular orbital theoretical study on the stability of conformations and chemical reactivity of 0,0-diethylphenylphosphate derivatives were carried out by EHT and CNDO/2 molecular orbital calculation method. The results shown that the dipole moment(${\mu}$) and total energies of the ${\theta}=90^{\circ}$ conformer were ${\mu}=3.185D\;&\;E_t=-162.6479(au)$ and also that of the ${\theta}=0^{\circ}$ conformer were ${\mu}=5.596D\;&\;E_t=-162.4013(au)$, respectively. Therefore, the values of ${\mu}\;&\;E_t$ of the ${\theta}=90^{\circ}$ conformer were much smaller than that of the ${\theta}=0^{\circ}$ conformer. The form with angle of rotation ${\theta}=90^{\circ}$ of phenyl ring was shown to be most stable and this was interpreted in terms of electrostatic and steric effect. 0,0-diethylphenylphosphate derivatives are predicted to increase both charge and orbital controlled $SN_2$ reactivity of the electron withdrawing substituent reduces the HOMO & LUMO energy, while the electron withdrawing substituent due to increase in positive charge of phosphorus atom of phosphate molecule.

• Analytical Science and Technology
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• v.19 no.2
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• pp.131-141
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• 2006

Hydrobromic acid salt of a $N_2O_2$ tetradentate ligand, N,N'-bis(2-hydroxybenzyl)-ethylene-diamine ($H-BHE{\cdot}2HBr$) was synthesized. $Br-BHE{\cdot}2HBr$, $Cl-BHE{\cdot}2HBr$, $CH_3-BHE{\cdot}2HBr$ and $CH_3O-BHE{\cdot}2HBr$ having Br, Cl, $CH_3$ and $CH_3O$ substituents at 5-position of the phenol group of $H-BHE{\cdot}2HBr$ were also synthesized. $Nap-BHE{\cdot}2HBr$ having naphthalen-2-ol instead of the phenol group was also synthesized. The potentiometry study in aqueous solution revealed that the proton dissociations of the synthesized ligands occurred in four steps and the order of the calculated overall proton dissociation constants (${\log}{\beta}_p$) of each ligand was Br-BHE < Cl-BHE < H-BHE < Nap-BHE < $CH_3$-BHE < $CH_3O$-BHE. The order showed a similar trend to that of Hammett substituent constants(${\sigma}_P$). The order of the stability constants (${\log}K_{ML}$) was CO(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II). The order in their stability constants (${\log}K_{ML}$) of each transition metal complex agreed well with that of the overall proton dissociation constants (${\log}{\beta}_p$).

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.400-405
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• 1987

The two dissociation constants of three amino acid, glycine, alanine, and tryptophan were measured by the conductometric method in the temperature from 15 to 35$^{\circ}$C and pressure up to 2,500bar in aqueous solution. The both dissociation constants were increased as the temperature increased but the pressure effect were not same as the temperature effect. The first constants were increased as the pressure increased but second constants were decreased except tryptophan. The characteristic properties of these amino acids were discussed from the thermodynamic properties of the dissociation reaction. The substituted effects of the reaction were deduced from Hammett reaction and substituted constants which were calculated from the dissociation constants.

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.7-13
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• 2007

The oxazole plays an important role in the binding of lexitropsin to the guanine-cytosine base pair from minor groove of DNA. The geometry optimization is performed with DFT calculations for the two possible conformations of the protonated oxazole. The proton affinities are calculated at B3LYP level of theory with 6-31G* basis set for the optimized geometry. It is found that the proton affinites of the conformations in which the oxazole nitrogen is the protonation center are greater than that of the conformations in which the oxazole oxygen is the protonation center. This result is in good agreement with molecular electrostatic potential (MEP) contour map. The proton affinities are also studied for various substituted oxazoles with the electron-donating and -withdrawing groups to estimate substitutent effect on the proton affinity at the hydrogen bonding site of the oxazoles. it is shown that the electron-donating substituents increase the proton affinity of oxazole, while the electron-withdrawing substituents decrease it.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.3 s.116
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• pp.13-22
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• 2006

The analogs of cyclic hydroxamic acids containing N-OH group have been proposed to play effective laccase-mediators in kraft pulp bleaching with laccase/mediator system. The existing mediators (NHA, 1-HBT, VA), the best laccase-mediators reported so far, and selected several analogs of cyclic hydroxamic acids were evaluated as a laccase-mediator for kraft pulp bleaching. It was found that NHA was the most effective mediator for the Trychophyton sp. LKY-7 laccase (TrL) in kraft pulp bleaching with TrL/mediator system, increasing about 10% ISO of brightness and decreasing about 2.8 of kappa number after alkaline-peroxide bleaching. Of the cyclic hydroxamic acidstested, the NHP.1(N-hydroxypyridone analog) was shown to enable TrL to effectively degrade lignin in kraft pulp bleaching, demonstrating approximately similar effect with that of NHA. However, the effect of substituent patterns of cyclic hydroxamic acid analogs in kraft pulp bleaching was not observed. The inhibitions of NHA and NHP.1 on TrL were not exhibited in TrL/mediator system. As a new mediator for TrL, NHP.1 was considered to be able to use in kraft pulp bleaching with TrL/mediator system.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.433-437
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• 2007

Bis(dithiobenzil) metal complex, used as functional NIR absorbing dye and photostabilizer, was synthesized using bezoin and anisoin as intermediate compounds. And squarylium, a charge generation material, was synthesized to find its photostability effect. The structure of the product was determined by $^1H-NMR$ and FT-IR and the thermal property was analyzed by DSC and TGA. Optical property and photostability were determined by UV-Vis-NIR spectroscopy. High absorbance was obtained in the NIR range and maximum absorbing wavelength was shifted depending on the nature and position of substituent in the bis(dithiobenzil) metal complex. The photofading effect of squarylium decreased by the addition of bis(dithiobenzil) metal complex.