• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1697-1702
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• 2011

A facile, green, efficient and environment-friendly protocol for the synthesis of 14-aryl- or alkyl-14Hdibenzo[a,j]xanthene, 1,8-dioxooctahydroxanthene and 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one have been developed by one-pot condensation of various aldehydes with (i) ${\beta}$-naphthol (ii) cyclic 1,3-dicarbonyl compounds and (iii) ${\beta}$-naphthol and cyclic 1,3-dicarbonyl compounds, in the presence of 1,3,5-trichloro-2,4,6-triazinetrion (trichloroisocyanuric acid, TCCA) as catalyst under solvent-free conditions. The present approach offers the advantages of clean reaction, simple methodology, short reaction time, easy purification, and economic availability of the catalyst.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.339-343
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• 2010

A series of $Ce_1Mg_xZr_{1-x}O_2$ (CMZO) mixed metal oxide with different molar ratio were prepared by simple co-precipitation method. The prepared materials were tested for their catalytic activity performance using Knoevenagel condensation of various aromatic aldehydes with barbituric acid under solvent-free condition in microwave. The best catalytic activity was obtained with CMZO (1:0.6:0.4). The synthesized materials were characterized by using XRD, FT-IR, SEM-EDS techniques.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2819-2821
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• 2013

• Journal of the Korean Chemical Society
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• v.61 no.4
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• pp.151-156
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• 2017

A simple, green and chemo-selective method for the N-benzyloxycarbonylation of amines, ${\beta}$-amino alcohols, ${\alpha}$-amino esters and sulfonamides has been developed under microwave irradiation. Good to excellent yields of the N-benzyloxycarbamates compounds were obtained in short times without any side products.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.546-548
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• 2001

Neat chlorosulfonic acid reacts with silica gel to give silica sulfuric acid in which sulfuric acid is immobilized on the surface of silica gel via covalent bond. A combination of silica sulfuric acid and wet SiO$_2$ was used as an effective deacetalizating agent for the conversion of acetals to their corresponding carbonyl derivatives by using microwave irradiation under solvent free conditions.

• Current Research on Agriculture and Life Sciences
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• v.28
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• pp.25-29
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• 2010

The colored sweet potato, particularly purple sweet potato, has been well known to contain anthocyanins abundantly. This study was conducted to examine the antioxidant properties of purple sweet potato. The chopped purple sweet potato was extracted 2 times with water or acetone for 18 hours at $28^{\circ}C$. The antioxidative potential of each solvent extract was assessed by DPPH free radical scavenging activity assay, FRAP assay, and total phenolic contents. The results showed that both extracts had not only high DPPH free radical scavenging activity but had high level of total phenolic compounds. Furthermore, both solvent extracts were found to have antioxidative effects in human colon cancer cells (HCT 116, HT 29) in DCFDA assay. The notable antioxidant activity of purple sweet potato suggests its significant health benefit and deserves further study to develop into functional food ingredient.

• Journal of Microbiology and Biotechnology
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• v.10 no.1
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• pp.99-102
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• 2000

To establish optimal conditions for esterification by Candida cylindracea, lipase reactions were performed simultaneously, separately, or individually in the varying initial rates of $0.014-0.060\mu$mole free fatty acids consumed min-1g-1. The reactants which were conditioned at aw of 0.12 gave the highest initial rate of esterifying $0.060\mu$mole free fatty acids consumed min-1g-1. These results suggest that the esterifying activity of lipase in an organic system depends on the transfer of available water within the reaction system.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2382-2388
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• 2007

A series of dimethine cyanine dyes were synthesized in a fast, efficient and high yield by the condensation of quaternary salts with 1H-indole-3-carbaldehyde in the presence of piperidine under solvent-free microwave irradiation. The products were identified by 1H NMR, IR, UV-Vis spectra and elemental analysis. The absorption and fluorescence properties of these dyes were investigated both experimentally and theoretically. Calculations performed at a combination of time-dependent density functional theory (TD-DFT) and the polarizable continuum model (PCM) reproduced the π-π* type absorption bands of the dyes. Regression analysis was used for studying theoretical results of the absorption maxima in different solvents. Compared with experimental counterparts, estimated overall uncertainties in the absorption maxima were about ±2%.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3677-3680
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• 2013

Novel tri- and tetra-substituted pyrimido[4,5-d]pyridazines-2(1H,3H,7H)-ones have been synthesized via the regiospecific condensation reaction of hydrazine derivatives with 5-acetyl-4-aryloyl-6-methyl-3,4-dihydropyrimidinones in the presence of $SiO_2-Y(NO_3)_3$ as a green and recyclable catalyst under solvent-free conditions. All products were obtained in high yields and short reaction time. Employing this method is in accord with green chemistry principles.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2657-2660
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• 2011

1,2,4-Triazoles and quinoxalines were found to display various pharmacological activities. Hence a series of 1-aryl-4-methyl-1,2,4-triazolo[4,3-a]quinoxalines were synthesized. Due to various advantages of organic reactions under solvent-free conditions these compounds were developed using iodobenzene diacetate under solvent-free conditions. The synthesized compounds were characterized by elemental microanalysis, infrared spectroscopy, $^1H$ NMR, $^{13}C$ NMR and HRMS. All the synthesized compounds were investigated for their antitubercular activity and 5g was found to the most active compound.