• Journal of the Korean Chemical Society
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• v.43 no.2
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• pp.237-240
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• 1999

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.500-504
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• 2001

• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.274-276
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• 2001

• Applied Chemistry for Engineering
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• v.18 no.6
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• pp.562-567
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• 2007

The stereoselective synthesis of chiral terminal epoxide is of immense academic and industrial interest due to their use as versatile starting materials as well as chiral intermediates. In this study, new polymeric chiral Co(salen) complexes bearing tallium (III)chloride and iron (III)chloride (ferric chloride) have been synthesized and characterized. Their catalytic activity and selectivity have been demonstrated for the asymmetric ring opening of various terminal epoxides using water and phenol derivatives as nucleophiles. The easily prepared polymeric complexes exhibited very high enantioselectivity for the asymmetric ring opening of epoxides with $H_2O$ and phenol nucleophiles, providing enantiomerically enriched terminal epoxides (> 98% ee). The system described in this work is very efficient for the synthesis of chiral epoxide, 1,2-diol and ${\alpha}$-aryloxy alcohol intermediates.

• Journal of the Korean Chemical Society
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• v.38 no.6
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• pp.442-448
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• 1994

The rate constants of the nucleophilic reaction of ${\alpha}$-(n-butyl)-N-phenylnitrone and its derivatives have been determined by ultraviolet spectrophotometry at $25^{\circ}C$ and a rate equation which can be applied over a wide pH range was obtained. Final product of the addition reaction was $\alpha$-phenylthiobutylidene-aniline. Base on the rate equation, genernal base effect, substituent effect and final product, plausible mechanism of addition reaction have been proposed. Below pH 3.0 the reaction was inititated by the addition of thiophenol, and in the range of pH 3.0∼10.0, proceeded by the competitive addition of thiophenol and thiophenoxide anion. Above the pH 10.0, the reaction proceeded through the addition of a thiophenoxide anion.

• Korean Journal of Plant Tissue Culture
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• v.21 no.6
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• pp.333-339
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• 1994

Enzyme activities and phenolic compound were compared to investigate the physiological characteristics during shoot formation from diploid and haploid of Nicotiana tabacum w BY4. The Nakata medium with 1.0 mg/L IAA, 0.5 mg/L Kinetin and 3 g/L activie carbon was excellent to induce the haploid plants from the middle size anther within 30 days after culture. The MS medium with 0.5 mg/L 2,4-D was good for callus induction from leaf explants of diploid and haploid, and a lot of plane were regenerated from calli on the MS medium supplemented with 2.0 mg/L BAE Activities of peroxidase for both of diploid and haploid plane were the highest at 2.0mg/L BAP Activities of IAA oxidase and catalase of haploid Plants were high or than those of diploid plants. On the other hand, activity of peroxidase of haploid plants were lower than those of diploid plants.

• The Korean Journal of Pesticide Science
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• v.10 no.1
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• pp.66-68
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• 2006

New synthetic method of 2-mercaptobenzoxazoles and 2-mercaptobenzimidazoles was established using elemental sulfur, dichloromethane, inorganic base and catalysts in alcohol solvents. This reaction condition gave products in high yields.

• Journal of the Korean Chemical Society
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• v.34 no.3
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• pp.267-279
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• 1990

The adsorption mechanisms of phenols on XAD-2 and XAD-7 resins were studied by using the distribution coefficient(log Kd) measured in the optimum adsorption conditions. It was observed that the Langmuir adsorption isotherm, indicating a molecular size-dependent adsorption, was appropriate for characterizing the adsorption behaviors of phenols on XAD-2 and XAD-7 resins. The adsorption energies of phenols on XAD resins were calculated by Lennard-Jones potential equation. In the calculation of the adsorption energy, the molecular radii and dipole moments of the resins and phenols were calculated by their van der Waals volumes and Debye equation, respectively. The stacking factor (F) were determined from the radio of the equilibrium distance to the stacking distance of molecules. In order to explain the adsorption energy calculated from the stacking factor it was compared with the adsorption enthalpy for each of phenols which was experimentally determined by batch adsorption shake method. It was observed that the adsorption enthalpy of phenolate ions on the XAD resins was likely to be more seriously affected by dispersion interaction than by a dipole or a charge interaction.

• Korean journal of applied entomology
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• v.50 no.2
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• pp.107-113
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• 2011

Benzylideneacetone (BZA) is a compound derived from culture broth of an entomopathogenic bacterium, Xenorhabdus nematophila (Xn). Its immunosuppressive activity is caused by its inhibitory activity against eicosanoid biosynthesis. This BZA is being developed as an additive to enhance control efficacy of other commercial microbial insecticides. This study was focused on the enhancement of the immunosuppressive activity of BZA by generating its chemical derivatives toward decrease of its hydrophobicity. Two hydroxylated BZA and one sugar-conjugated BZA were chemically synthesized. All derivatives had the inhibitory activities of BZA against phospholipase $A_2$ ($PLA_2$) and phenoloxidase (PO) of the diamondback moth, Plutella xylostella, but BZA was the most potent. Mixtures of any BZA derivative with Bacillus thuringiensis (Bt) significantly increased pathogenicity of Bt. BZA also inhibited colony growth of four plant pathogenic fungi. However, BZA derivatives (especially the sugar-conjugated BZA) lost the antifungal activity. These results indicated that BZA and its derivatives inhibited catalytic activities of two immune-associated enzymes ($PLA_2$ and PO) of P. xylostella and enhanced Bt pathogenicity. We suggest its use to control plant pathogenic fungi.

• Journal of the Korean Chemical Society
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• v.34 no.2
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• pp.189-196
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• 1990

8-Acyl-2-hydroxyphenazine-5,10-dioxides and 8-acyl-2-aminophenazine-5,10-dioxides were synthesized by the reaction of hydroquinone and 4-aminophenol with 6-acylbenzofuroxans which had been obtained from acetanilide and n-acyl chlorides bearing butanoyl, hexanoyl and octanoyl groups. The antimicrobial activities of these phenazine dioxide derivatives were investigated in terms of minimum inhibitory concentration by the common twofold dilution technique. It was observed that the antimicrobial activity of the phenazine dioxide derivatives bearing octanoyl group was stronger than that of those bearing butanoyl and hexanoyl groups in gram positive microorgamisms, but it was observed that the antimicrobial activity and the number of the carbon atom of acyl groups did not have any relation in gram negative microorganisms. When the activity of xanthine oxidase which is the key enzyme in the generation of superoxide anion radical ($O_2^-$), was measured in the presence of phenazine dioxide derivatives, the inhibitory action of the enzyme activity of 8-acyl-2-hydroxyphenazine-5,10-dioxides was increased in accordance with the number of the carbon atom of acyl groups.