• Macromolecular Research
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• 제8권2호
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• pp.80-88
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• 2000

Biodegradable microspheres were prepared with poly(L-lactide-co-glycolide) (PLGA, 75 : 25 by mole ratio) by an oil/oil solvent evaporation method for the sustained release of anti-AIDS virus agent, AZT The microspheres of relatively narrow size distribution (7.6$\pm$ 3.8 ㎛) were obtained by controlling the fabrication conditions. The shape of microspheres prepared was smooth and spherical. The efficiency of AZT loading into the PLGA microsphere was over 93% compared to that below 15% for microspheres by a conventional water/oil/water method. The effects of Preparation conditions on the morphology and in vitro AZT release pattern were investigated. in vitro release studies showed that different release pattern and release rates could be achieved by simply modifying factors in the fabrication conditions such as the type and amount of surfactant, initial amount of loaded drug, the temperature of solvent evaporation, and so on. PLCA microspheres prepared by 5% of initial drug loading, 1.0% (w/w) of surfactant concentration, and 25$\^{C}$ of solvent evaporation temperature were free from initial burst effect and a near-zero order sustained release was observed. Possible mechanisms of the near-zero order sustained release for our system have been proposed.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1219-1222
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• 2010

A simple and efficient method has been developed for conversion of arenecarbaldehyde-3-methylquinoxalin-2-ylhydrazones to 3-(2-methylquinoxalin-3-yl)-2-(substitutedphenyl)thiazolidin-4-ones in good yields using microwave irradiation technique on silica as solid support under solvent free conditions. The synthesized compounds were characterized by elemental microanalysis, infrared spectroscopy, $^1H$ NMR, and mass spectroscopy. All the synthesized thiazolidinones were investigated for their antimicrobial and antifungal activities. The results of the biological activities revealed that the compounds 3b, 3d, 3f and 3h exhibited excellent antibacterial activities while 3d and 3h exhibited good antifungal activity.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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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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• 제34권12호
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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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• 제32권2호
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• pp.630-634
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• 2011

Solvent-free conversion of various epoxides to their corresponding $\beta$-hydroxy thiocyanates was carried out successfully with $NH_4SCN$/zeolite molecular sieve $4{\AA}$ system at room temperature. The reactions were completed within 2 - 7 min to give thiocyanohydrins with perfect regioselectivity and isolated yields. Moreover, the zeolite can be reused for several times without losing its activity.

• 대한화학회지
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• 제57권4호
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• pp.472-475
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• 2013

An efficient and environmentally benign protocol for the three-component synthesis of triazoloindazoles and indazolophthalazines via condensation of dimedone, aldehydes and urazole or phthalhydrazide catalyzed by $ZrOCl_2.8H_2O$ as an inexpensive and eco-friendly catalyst with high catalytic activity under solvent-free conditions is reported. This protocol provides a new and improved method for obtaining triazoloindazoles and indazolophthalazines in terms of good yields, simple experimental procedure and short reaction time.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.123-127
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• 2012

A facile and simple procedure for the synthesis of novel and known calix[4]resorcinarene derivatives were developed via a reaction of arylaldehydes with resorcinol in the presence of catalytic amounts of tungstate sulfuric acid (TSA) under solvent-free conditions. This eco-friendly method has many appealing attributes, such as excellent yields, short reactions times, use of safe and recoverable catalyst, and simple work-up procedures. TSA was characterized by powdered X-ray diffraction (XRD), X-ray fluorescence (XRF) and FTIR spectroscopy.

• 대한화학회지
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• 제57권2호
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• pp.260-263
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• 2013

An efficient and environmentally benign protocol for the pseudo four-component synthesis of benzopyranopyrimidines via condensation of salicylic aldehydes, malononitrile and various amines catalyzed by $ZrOCl_2{\cdot}8H_2O$ as an inexpensive and eco-friendly catalyst with high catalytic activity under solvent-free conditions is reported. This protocol provides a new and improved method for obtaining benzopyranopyrimidines in terms of good yields, simple experimental procedure and short reaction time.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.566-568
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• 2004

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1399-1402
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• 2011