• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2213-2218
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• 2012

Efficient synthetic routes were developed to prepare a sizable amount (4-15 grams) of the chiral epoxides 4-6 as versatile intermediates for the synthesis of aspartyl protease inhibitors of therapeutic interest such as HIV protease and ${\beta}$-secretase. Oxidative cleavage of the C(2)-C(3) double bond of L-ascorbic acid followed by functional group manipulation led to the preparation of the epoxide 10, which was opened with an azide to yield a common aziridine intermediate 12. Through opening of the aziridine ring of 12 with either a carbon or a sulfur nucleophile, chiral epoxide precursors 4-6 could be prepared for various HIV protease inhibitors. Except for the final low melting epoxides 5 and 6, all intermediates were obtained as crystalline solids, thus the synthetic pathway can be easily applied to a large-scale synthesis of the chiral epoxides.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.695-696
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• 2014

• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1417-1420
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• 2004

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1899-1902
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• 2013

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.875-883
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• 2013

Ten new derivatives of 1,3-diazabicyclo[3.1.0]hex-3-enes linked via ether linkage to chalcones were synthesized and characterized by UV, FT-IR, $^1H$ NMR and $^{13}C$ NMR spectral techniques. The spectra of all synthesized compounds, confirmed structure-photochromic behavior relationships (SPBR) both in solution or in solid state by irradiation under UV light at 254 nm. In other efforts for first time photochromic behavior of ketoaziridines has been investigated.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.699-700
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• 2014

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.240.3-241
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• 2001

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3123-3126
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• 2009

• Polymer(Korea)
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• v.37 no.5
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• pp.587-591
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• 2013

Poly(3,4-ethylenedioxythiophene) (PEDOT) has good properties such as high conductivity, optical transmittance, and chemical stability, while offering relatively weak physicochemical properties. The main purpose of this paper is the improvement of physicochemical properties such as solvent resistance and pencil hardness of PEDOT. Carboxyl groups in the anionic type waterborne polyurethane (WPU) chains can effectively crosslink each other in the presence of aziridine, resulting in physicochemically robust PEDOT/WPU organic-organic hybrid conductive thin films. The electrical conductivity, optical properties, and physicochemical properties of the hybrid conductive film were compared by varying the solid content and WPU portion in the coating precursor solution. From the results, the transparency and surface resistance of the hybrid film show a decreasing tendency with increasing solid content in the coating precursor. Moreover, solvent resistance and hardness were dramatically enhanced by hybridization of PEDOT and crosslinked WPU due to curing reactions between carboxyl groups.

• Polymer(Korea)
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• v.33 no.4
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• pp.326-332
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• 2009

New humidity-sensitive monomer, N-methacryloyl-N'-ethyl-N'-propyl piperazinium bromide (MANEPPB) was prepared by the quaternization reaction of N-methacryloyl-N'-ethyl piperazine (MANEP) with 1-bromopropane. Polyelectrolytes derived from the copolymers composed of MANEPPB/MMN/AA=60/35/5, 70/25/5, 80/15/5, 90/5/5 and 95/0/5 were prepared for the humidity-sensitive membranes, which were fabricated on the gold electrode by dipping method and were crosslinked by reacting copolymers with aziridine crosslinker, trimethylolpropane tris(2-methyl-1-aziridinopropionate) (TTAP). When the resistance dependences on the relative humidity of the sensors were measured, it was found that the resistance varied three orders of magnitude between 20 and 90%RH, which was satisfied with the requirement for the common humidity sensor operating at ambient humidity. Their hysteresis, temperature dependence, frequency dependence, response and recovery time and water durability were measured and evaluated as a humidity-sensing membrane.