• YAKHAK HOEJI
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• v.41 no.1
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• pp.7-13
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• 1997

A regiospecific total synthesis on the precursor(18b) of rhodomycinones is described. The anion of 3-carbomethoxy-1(3H)-isobenzofuranone(13) was respectively condensed wi th naphthalenone (12) and butenoate(8) derivatives which were, prepared by two different synthetic routes to afford 9-ethyl-6,7-dihydroxy 7,8,9,10-tetrahydronaphthacene-5,12 dione(18b) after oxidation and reduction.

• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1385-1391
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• 2004

A general route for the synthesis of optically active unhindered aliphatic alcohols, where the steric demands between two alkyl groups adjacent to the carbinol are similar, with high enantiomeric purity has been developed by sulfoxifation of chiral ${\beta}$-hydroxy sulfides, followed by alkylation and desulfurization.

• Bulletin of the Korean Chemical Society
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• v.20 no.5
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• pp.551-555
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• 1999

11-Deoxydaunomycinone 15 and 10-fluoroanthracyclinone derivatives 9, 10 were obtained. Naphthalenone 4 prepared from 2-(2,4-pentadienyl)-1,3-dioxane 2 with methyl vinyl ketone and hydrolysis with HClO4 was condensed with phthalidesulfone 5 through Michael type reaction, and was converted to 7 by epoxidation. Epoxide 7 was transformed to trione 12 using reduction-oxidation or hydrofluorination process, and then to 15 by introducing several functional groups. Compound 8 obtained in the course of the reaction of epoxide 7 and HF/ Pyr was used for the synthesis of compounds 9, 10.

• YAKHAK HOEJI
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• v.41 no.4
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• pp.480-483
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• 1997

The efficient synthesis of p-(acetylamino)phenylacetic acid(7), a antirheumatic agent, is reported. Methyl phenylacetate(3) was prepared from Friedel- Crafts reaction of benzene with methyl ${\alpha}$-chloro-${\alpha}$-(methylthio)acetate(1) followed by reductive desulfurization with zinc dust in acetic acid. Compound(7) was obtained from 3 by a sequence of nitration, reduction, N-acylation, and hydrolysis.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.240-248
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• 1973

Reduction of penta-O-acetyl-myo-inosose-2 by catalytic hydrogenation and with sodium-amalgam was carried out in alcohol solution of pH $3{\sim}4$. The former reduction product was axial-alcohol, and the latter equatorial-alcohol. On reduction of penta-O-acetyl-DL-epi-inosose-2 with sodium borohydride and sodium-amalgam in the previous condition, ax.-alcohol and eq.-alcrhol have been obtained. The synthesis of various inositol-p-hydroxybezoate are described. The esters have been characterized by paper chromatography and saponification, and their antimicrobial activities on some microbes were tested for the application of food industry. As the result, it was found that the antimicrobiol activity of epi-inositol ester was superior to its analogues.

• Korean Journal of Materials Research
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• v.23 no.11
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• pp.631-637
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• 2013

Synthesis of sub-micron $2SnO{\cdot}(H_2O)$ powders by chemical reduction process was performed at room temperature as function of viscosity of methanol solution and molecular weight of PVP (polyvinylpyrrolidone). Tin(II) 2-ethylhexanoate and sodium borohydride were used as the tin precursor and the reducing agent, respectively. Simultaneous calcination and sintering processes were additionally performed by heating the $2SnO{\cdot}(H_2O)$ powders. In the synthesis of the $2SnO{\cdot}(H_2O)$ powders, it was possible to control the powder size using different combinations of the methanol solution viscosity and the PVP molecular weight. The molecular weight of PVP particularly influenced the size of the synthesized $2SnO{\cdot}(H_2O)$ powders. A holding time of 1 hr in air at $500^{\circ}C$ sufficiently transformed the $2SnO{\cdot}(H_2O)$ into $SnO_2$ phase; however, most of the PVP (molecular weight: 1,300,000) surface-capped powders decomposed and was removed after heating for 1 h at $700^{\circ}C$. Hence, heating for 1 h at $500^{\circ}C$ made a porous $SnO_2$ film containing residual PVP, whereas dense $SnO_2$ films with no significant amount of PVP formed after heating for 1 h at $700^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.56 no.5
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• pp.497-505
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• 2019

Lanthanum-based transition metal cations containing perovskites have emerged as potential catalysts for the intermediate-temperature (600-800℃) oxygen reduction reaction (ORR). Here, we report a facile acetylacetone-assisted combustion route for the synthesis of nanostructured La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF6428) cathodes for intermediate-temperature solid-oxide fuel cells (IT-SOFCs). The as-prepared powder was analyzed by thermogravimetry analysis-differential scanning calorimetry. The powder calcined at 800℃ was characterized by X-ray diffraction, scanning electrode microscopy, energy dispersive X-ray spectroscopy, and Brunauer-Emmett-Teller surface area measurements. It was found that the porosity of the air electrode significantly increased by utilizing the nanostructured LSCF6428 instead of commercial powder. The performance of a single cell fabricated with the nanostructured LSCF6428 cathode increased by 112%, from 0.4 to 0.85 W cm^-2, at 700℃. Electrochemical impedance spectroscopy showed a considerable reduction in the area-specific resistance and activation energy from 133.5 to 61.5 kJ/mol, resulting in enhanced electrocatalytic activity toward ORR and overall cell performance.

• Journal of Powder Materials
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• v.11 no.3
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• pp.253-258
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• 2004

We report a carbothermal reduction process for massive synthesis of monolithic W$_{18}$O$_{49}$ phase from tungsten oxide in the presence of carbon source. Carbon black powder was used as a carbon source and added to WO$_3$ by 40 weight percent. Bundles of W$_{18}$O$_{49}$ rods were formed over the temperature range of 80$0^{\circ}C$$^{\circ}C$ to 90$0^{\circ}C$. Pure W$_{18}$O$_{49}$ bundles could be separated from the mixture of W$_{18}$O$_{49}$ and residual carbon black powder. Field emission character of W$_{18}$O$_{49}$ phase was determined using the extracted W$_{18}$O$_{49}$ rods. Flat lamp fabricated from the W$_{18}$O$_{49}$ rods showed the turn-on field of 9.3 V/${\mu}m$.

• Journal of the Korean institute of surface engineering
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• v.56 no.6
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• pp.386-392
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• 2023

In this work, we describe the reduction kinetics of gold nanoparticles synthesized by plasma discharge in aqueous solutions with varied voltages and precursor (HAuCl₄) concentrations. The reduction rate of [AuCl₄]^- was determined by introducing NaBr to the gold colloidal solution synthesized by plasma discharge, serving as a catalyst in the reduction process. We observed that [AuCl₄]^- was completely reduced when its characteristic absorption peak at 380 nm disappeared, indicating the absence of [AuCl₄]^- for ligand exchange with NaBr. The reduction rate notably increased with the rise in discharge voltage, attributable to the intensified plasma generated by ionization and excitation, which in turn accelerated the reduction kinetics. Regarding precursor concentration, a lower concentration was found to retard the reduction reaction, significantly influencing the reduction kinetics due to the presence of active H⁺ and H radicals. Therefore, the production of strong plasma with high plasma density was observed to enhance the reduction kinetics, as evidenced by optical emission spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1808-1846
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• 2011

From 1975 to 2011, for thirty six years, the author and his collaborators have developed a variety of reducing and hydroborating agents, and applied them to organic synthesis, which involves the 1,2-reduction of ${\alpha}$,${\beta}$-unsaturated carbonyl compounds, stereoselective reduction of cycloalkanones, regioselective ring-opening of epoxides, partial reduction of carboxylic acid derivatives to aldehydes, regioselective addition to carbon-carbon multiple bonds, etc. by utilizing metal hydrides and the newly-devised the Meerwein-Ponndorf-Verley (MPV) type reagents. Such developments provide a new synthetic methodology making possible valuable selective reductions and hydroborations, not practical previously.