• Bulletin of the Korean Chemical Society
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• v.3 no.3
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• pp.92-98
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• 1982

Solvolysis reactions of some substituted benzoyl chlorides were studied in ethanol-water, ethanol-trifluoroethanol and methanol-acetonitrile mixtures. Results showed that the reaction proceeds via an $S_N2$ process in which bond formation is more advanced than bond cleavage. Comparison of the two models for predicting transition state variation indicated superior nature of the quantum mechanical model relative to the potential energy surface model.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.420-422
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• 1990

Various substituted benzal chlorides are converted into alkyl phenylacetates ($ArCH_2COOR$) under CO atmosphere on reaction with a catalytic amount of Fe(CO)$_5$, a base, and an alcohol. The optimum conditions are found as atmospheric pressure of CO, 40$^{\circ}C$, potassium hydroxide as base, and medium of alcohol.

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.425-428
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• 1986

A new heterocuprate containing 2-pyridyloxy ligand, lithium 2-pyridyloxy-n-butylcuprate, has shown improved thermal stability and it reacts with acid chlorides to afford the corresponding ketones in high yields. Similarly, it can be effectively utilized in conjugate addition reactions of $\alpha,\beta$-unsaturated ketones. Of synthetic significance is that the complete utilization of n-butyl group in lithium 2-pyridyloxy-n-butylcuprate has been observed.

• Journal of the Korean Chemical Society
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• v.48 no.4
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• pp.385-393
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• 2004

2-Ethoxycarbonyl-3-methylquinoxaline 1,4-dioxide (8) was synthesized from benzofuroxan and ethyl acetoacetate. The reaction of compound 8 with hydrazine hydrate or selenium dioxide gave 2-hydrazinocarbonyl-3-methylquinoxaline 1,4-dioxide (9) or 2-ethoxycarbonyl-3-formylquinoxaline 1,4-dioxide (10), respectively. The reaction of compound 9 with alkanoyl chlorides, benzoyl chlorides, heteroacyl chlorides, and benzenesulfonyl chlorides afforded 3-methyl-2-(substituted hydrazinocarbonyl)quinoxaline 1,4-dioxides (11-14), respectively. The reaction of compound 9 with sodium azide gave 2-azidocarbonyl-3-methylquinoxaline 1,4-dioxide (15), and then its refluxing in dioxane/alcohols resulted in the Curtius rearrangement to give N-(3-methyl-1,4-dioxoquinoxalin-2-yl)-alkyl carbamates (16). The reaction of compound 15 with substituted anilines afforded 2-(3-substituted phenylureido)-3-methylquinoxaline 1,4-dioxides (17). The reaction of compound 10 with benzoic hydrazide or substituted anilines provided quinoxaline 1,4-di-oxides (18, 19), respectively. The herbicidal and fungicidal activities of the synthesized compounds were investigated.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.672-680
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• 2015

As a global regulatory gene in Streptomyces, afsR can activate the biosynthesis of many secondary metabolites. The effect of afsR on the biosynthesis of a phenazine metabolite, lomofungin, was studied in Streptomyces lomondensis S015. There was a 2.5-fold increase of lomofungin production in the afsR-overexpressing strain of S. lomondensis S015 N1 compared with the wild-type strain. Meanwhile, the transcription levels of afsR and two important genes involved in the biosynthesis of lomofungin (i.e., phzC and phzE) were significantly upregulated in S. lomondensis S015 N1. The optimization of metal chlorides was investigated to further increase the production of lomofungin in the afsR-overexpressing strain. The addition of different metal chlorides to S. lomondensis S015 N1 cultivations showed that CaCl₂, FeCl₂, and MnCl₂ led to an increase in lomofungin biosynthesis. The optimum concentrations of these metal chlorides were obtained using response surface methodology. CaCl₂ (0.04 mM), FeCl₂ (0.33 mM), and MnCl₂ (0.38 mM) gave a maximum lomofungin production titer of 318.0 ± 10.7 mg/l, which was a 4.1-fold increase compared with that of S. lomondensis S015 N1 without the addition of a metal chloride. This work demonstrates that the biosynthesis of phenazine metabolites can be induced by afsR. The results also indicate that metal chlorides addition might be a simple and useful strategy for improving the production of other phenazine metabolites in Streptomyces.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.769-776
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• 2010

Concrete structures immersed in seawater are exposed to uniform chloride concentration. However, seashore concrete structures are subjected to various airborne chlorides concentration depending on areas, distance from seashore, orientation of structures and wind direction etc. Therefore, structures which is not coming into direct contact with seawater are greatly affected by salt attack and those cases have been reported. This study intends to investigate salt attack by airborne chlorides in terms of the distance from the seashore based on the measurements conducted at 73 spots and 27 areas during 3 years in the Eastern, Western and Southern coasts of South Korea. Results revealed large regional variations of the salinity in coastal regions along with significant seasonal effects caused by seasonal winds. Moreover, the salinity is seen to diminish as the distance from the seashore increases at a rate corresponding to the function $y=ax^{-b}$. These results will be helpful to do the durability design and management of seashore structures.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.527-534
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• 1999

Solvolyses of para-substituted cinnamoyl chlorides in aqueous binary mixtures of acetone, ethanol, methanol were investigated at 25.0$^{\circ}C$. These data were interpreted using the Grunwald-Winstein relationship, Hammett equation, and quantum mechanical model. Grunwald-Winstein plots of the first-order rate constants for para-substituted cinnamoyl chlorides with $Y_{CI}$ showed marked dispersions into three separate curves for the three aqueous mixtures with a large m vaIue for aqueous alcohol solvents. This study has shown that the potential energy surface and quanturm mechanical model predict transition state variation correctly for $S_N1$ like $S_N2$ reaction mechanism of para-substituted cinnamoyl chlorides.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.573-576
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• 2008

When the concrete structures are in contact with seawater, concentration of chloride for estimating chloride diffusion coefficient can be defined as the chloride concentration of sea water. However, in case the concrete structures, constructed in the seashore, aren't directly in contact with seawater, it is difficult to establish the interface concentration of chloride. In addition, marine concrete structures are greatly affected by salt attack such as rebar corrosion, among the cause of salt attack, airborne chlorides is primary factor. Therefore, in this study, salt attack environment by airborne chlorides was investigated in terms of a seasonal distribution at 72 spots, 27 areas in the East, West, South coast for 3 years from July '03 to June '06. Results indicated that in the East and South coast, the amount of the airborne chlorides is comparatively higher in summer, in the West coast, higher in winter according to the seasonal wind.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.325-333
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• 1998

Under the seawater environment, the reinforced concrete structure is deteriorated due to physical and chemical attacks. The main deterioration mechanism is the chloride corrosion of reinforcing steel. The corrosion inhibitors have been used to protect the rebars from corrosion which are susceptible to chlorides in concrete. However, there is not clear conclusion about corrosion inhibitors yet. In this study, it is made the accelerated experiment with 3 kinds of corrosion inhibitors for various chloride ingresses. It is estimated corrosion inhibitors that inhibitors by Half-Cell Potential, corrosion area ratio and weight loss ratio. It is concluded that inhibitors are not effective to corrosion inhibition for excessive chloride ingress. However, the effect of inhibition is directly proportional ot contents of corrosion inhibitors in some chloride ingress.

• Journal of the Korean Applied Science and Technology
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• v.7 no.2
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• pp.11-18
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• 1990

N-alkyl carboxy pyridinium chlorides such as N-lauryl carboxy-pyridinium chloride, N-myristyl carboxy pyridinium chloride, N-cetyl carboxy pyridinium chloride and N-stearyl carboxy pyridinium chloride were synthesized by the reaction of nicotinic acid and isonicotinic acid with long chain alkyl chlorides, and N-alkyl pyrinium carboxylates such as N-lauryl pyridinium carboxylate, N-myristyl pyridinium carboxylate. N-cetyl pyridinium carboxylate and N-stearyl pyridinium carboxylate were prepared from N-alkyl carboxy pyridinium chlorides. These reaction products could be separated by both column chromatogrphy, and paper chromatography, and there dissociation constants of N-alkyl pyridinium carboxylates were found to pKa $1.0{\times}10^{13}{\sim}6,31{\times}10^{14}$.