• Natural Product Sciences
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• v.9 no.4
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• pp.213-219
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• 2003

Five aromatic compounds, of which two are new glucosides, and six flavonols were isolated and identified for the first time from the flower heads and aerial shoots of Helichrysum conglobatum (Asteraceae). Their structures were established on the basis of chemical and spectroscopic methods including UV, MS, 1D- and 2D-NMR. Some fractions and isolates were screened for anti-microbial activities. This is the first report of the isolation of the chemical constituents of this species.

• Journal of the Korean Chemical Society
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• v.47 no.2
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• pp.133-136
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• 2003

A series of oxazolone derivatives (4a-n) have been synthesized as a potential antibacterial agent. Titled compounds have been prepared by the condensation of aryloxy acetyl-amino-acetic acid with aldehyde in presence of ethanol, acetic anhydride and sodium acetate. The structures of the new compounds were established on the basis of $^1H$ NMR and IR spectral data.

• The Korean Journal of Food And Nutrition
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• v.28 no.4
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• pp.533-543
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• 2015

This study investigated the chemical composition of Artemisia princeps var. orientalis (Pampan) Hara (ssuk in Korea) essential oil and the quantitative changes of major terpene compounds according to the time of harvest. The essential oils obtained by hydrodistillation extraction from the aerial parts of ssuk were analyzed by GC and GC-MS. The essential oil composition of ssuk was characterized by higher contents of mono- and sesqui- terpene compounds. Ninety-nine volatile flavor compounds were identified in the essential oil from ssuk harvested in 2010, with camphor (11.9%), ${\beta}-caryophyllene$ (9.11%), dehydrocarveol (8.51%), and borneol (7.72%) being the most abundant compounds. Eighty-three compounds were identified in the essential oil from the plant harvested in 2011, with borneol (12.36%), caryophyllene oxide (12.29%), ${\beta}-caryophyllene$ (10.24%), camphor (9.13%), and thujone (8.4%) being the most abundant compounds. Eighty-four compounds were identified in the essential oil from the plant harvested in 2012, with ${\beta}-caryophyllene$ (20.25%), caryophyllene oxide (14.63%), and thujone (11.55%) being the major compounds. Eighty-nine compounds were identified in the essential oil from the plant harvested in 2013, with thujone (23.11%), alloaromadendrene oxide (12.3%), and ${\beta}-caryophyllene$ (11.48%) being the most abundant compounds. Thujone and aromadendrene oxide contents increased significantly from 2010 to 2013, while camphor and dehydrocarveol contents decreased significantly during those 4 years. The quantitative changes in these 4 compounds according to the time of harvest can served as a quality index for ssuk essential oil. The ecological responses to recent climate changes may be reflected in the chemical components of natural plant essential oils.

• Archives of Pharmacal Research
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• v.3 no.2
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• pp.87-88
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• 1980

The goal of this research is to provide information that will lead to the development of new non-phototoxic antimalarial compounds. The goal was approached by first learning the chemical mechanism of phototoxicity of six representative compounds 1a-f: a[(diethyl-, -dihexyl-, and -dioctyl- aminomethyl)]-2-(3', 4' -dichlorophenyl)-6-methoxy-4-quinolinemethanol (1a, 1b, and 1c) and .alpha. [(diethyl-, -dibutyl-, and -dihexyl-aminomethyl)]-2-(-4'-methoxyphenyl-6-methoxy-7-chloro-4-quinolinemethan ol (1d, 1e, and 1f). The photochemical reaction of these compounds was investigated in 2-propanol. Similar photochemical fragmentation reactions accurred in all compounds.

• Journal of the Korean Chemical Society
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• v.47 no.2
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• pp.89-95
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• 2003

We present improved correlations between theoretical and experimental determination of heat of formation of some aliphatic nitro compounds. The method is based on a previously given theoretical procedure, which is ameliorate through the introduction of suitable bond parameters. The comparison with available experimental data and previous theoretical estimation show a quite satisfactory improvement. Some possible further extensions are pointed out.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.484-488
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• 2006

The solid-phase synthesis of new series of 1,6,8-trisubstituted tetrahydro-2H-pyrazino[1,2-a]pyrimidine-4,7-diones as bicyclic $\beta$-turn mimetics is described. Their NF-kB inhibition activities were tested and the effect of substituents on bicyclic ring was investigated. Among the prepared compounds, the fluorobenzyl and methoxybenzyl group substituted compounds 26 and 27 at C-1 and C-8 position showed more inhibitory activities than the others. Tested at a concentration of 10 uM, these two compounds showed a 60% inhibition against the target NF kB 549.

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.221-226
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• 2013

A series of some novel 2-[5-(substituted phenyl)-[1,3,4]oxadiazol-2-yl]-benzoxazoles were synthesized by using benzoxazole-2-carboxylic acid on reaction with thionyl chloride in presence of ethanol solvent at room temperature gave benzoxazole-2-carbonyl chloride, which is turned into benzoxazole-2-carboxylic acid hydrazide on reaction with hydrazine hydrate in ethanol solvent under reflux. The subsequent treatment of benzoxazole-2-carboxylic acid hydrazide with an appropriate aromatic carboxylic acid in presence of polyphosparic acid under reflux afforded the title compounds. The chemical structures of the newly synthesized compounds were elucidated by their IR, $^1H$ NMR and Mass spectral data analysis. Further the compounds are used to find out their ability towards anti microbial and nematicidal activity.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.47-51
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• 2019

The three different polymer compounds were manufactured with the three different fire retardant (silane coated magnesium dihydroxide) contents, 180, 200, 220 phr, for making cable sheath for ship industry. In the research, ethylene-vinylacetate, polyethylene as matrix polymers and ethylene-vinylacetate grafted maleic anhydride as coupling agent were selected for compounding with fire retardant, closslinking agent, plasticizer, and other additives. In the evaluation. ΔT, Mooney viscosity, and tensile strength increased with the content of fire retardant. But it was found that too much fire retardant damaged aging resistance and cold resistance of the polymer compound.

• Bulletin of the Korean Chemical Society
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• v.17 no.11
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• pp.1023-1031
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• 1996

A new synthetic route for the lanthanum β-diketonate compounds via in-situ formed lanthanum alkyl complexes was developed in the process for the development of suitable MOCVD (metal-organic chemical vapor deposition) precursors of PLT, one of the promising material for the ferroelectric film. A series of lanthanum β-diketonate compounds were successfully synthesized by this method. This new method is found to have some merits; versatile method for almost every β-diketone, β-hydroxyketone, and β-hydroxyaldehyde, short reaction time, easy purification for high purity, moderate to high yield, and easy access to anhydrous compounds. In some cases, anhydrous oligomeric products fail to show the higher volatility. On the other hand, some lanthanum β-diketonates with aromatic groups such as La(1,3-biphenyl-l,3-propandione)3 are found to have favorable properties for a precursor of lanthanum oxide, one of major components of PLT, such as low melting point, and much higher decomposition temperature. A plausible pyrolysis mechanism is proposed by the TGA, where consecutive dissociation of R, CO, CH, C, and O fragments occurs.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.534-539
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• 2010

The adsorptive removal of organic sulfur compounds including tert-butylmercaptane(TBM), tetrahydrothiophene(THT) and dimethylsulfide(DMS) in methane was investigated over NaY and copper-exchanged NaY(CuNaY) zeolites at 303 K and atmospheric pressure. In the ternary adsorption system, the preferential adsorption of THT over other sulfur compounds on NaY and the concurrent adsorption of all sulfur compounds on CuNaY were achieved, which could be explained by the breakthrough curve, the temperature-programmed desorption, and the apparent activation energy for desorption. The sulfur uptake capacity of CuNaY(2.90~3.20 mmol/g) was much higher than that of NaY(0.70~0.90 mmol/g). A comparative study indicated that the $Cu^{1+}$ sites and acidity of CuNaY were probably responsible for the strong interaction with sulfur atom and high sulfur uptake abilities.