• Archives of Pharmacal Research
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• v.24 no.6
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• pp.503-507
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• 2001

trans-Metanicotine, a subtype (${\alpha}_4{\beta}_2$)-selective ligand for neuronal nicotinic acetylcholine receptor, is under clinical phase for Alzheimer's disease. An efficient synthetic route for ($\pm$)-methyl-(1-aryl-4-pyridin-3-yl-but-3-enyl)-am ices, derivatives of tracts-metanicotine, was explored. Allylation reaction of aryl aldimines with allylmagnesium bromide in THF gave ($\pm$)-methyl-(1-aryl-but-3-enyl)-amines. Protection of the amines with the Boc group and following Heck reaction of the N-Boc amines with 3-bromopyridine gave ($\pm$)-methyl-(1-aryl-4-pyridin-3-yl-but-3-enyl)-carbamic acid tert-butyl esters. Deprotection of the N-Boc group in aqueous 1 N-HCI solution gave the titled amines in good yields. Thus, trans-metanicotine analogues modified at the ${\alpha}-position$ of the methylamino group with amyl groups were obtained in 5 steps.

• Bulletin of the Korean Chemical Society
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• v.18 no.2
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• pp.156-161
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• 1997

Aqueous 6-hydroxyquinoline in the first excited singlet state undergoes protonation to the imine group first in 15 ps, then in the time scale of 40 ps deprotonation from the enol group and finally, however, quickly as in 11 ps electron rearrangement to change into a resonance hybrid structure of quinoid-prevailing forms. Despite the fact that the decay time constant is smaller than the formation time constant, fluorescence from excited protropic zwitterion is observed to assign its maximum at 510 nm. The electron rearrangement is basically an intramolecular charge transfer from the deprotonated oxygen atom to the positively charged iminium ring without any notable change in nuclear geometry, producing a zwitterionic quinoid structure with much a smaller electric dipole moment than the zwitterionic protropic species. This photoproduct formed by consecutive excited state proton and electron transfers shows a smaller dipole moment in S1 than in S0 and a hypsochromic shift although its S1 state has (π, π*) character.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.253.2-253.2
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• 2002

Apicidin. a natural product HDAC inhibitor. is recently isolated from Fusarium sp. at Merk Research Laboratories, induces therapeutic applications as a broad spectrum antiprotozoal agent to muti-drug resistant malaria and a potential antitumor agent. The biological activity of apicidin appears to be apicocomplexan HDAC at low nanomolar concentrations. (omitted)

• Polymer(Korea)
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• v.29 no.2
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• pp.135-139
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• 2005

In this study, poly(ethylene imine) (PEI) modified by methoxypoly(ethylene glycol) (mPEG) and folate as a gene carrier was synthesized to decrease cytotoxicity and to improve in vivo targeting. mPEG was modified by glutaric anhydride (GA) to endow carboxylic end group, followed by the activation reaction with EDC (N-ethyl-N'-(3-dimethyl-aminopropyl) carbodiimide) and NHS (N-hydroxysuccinimide). The activated carboxylic end group of mPEG was reacted with the amines of PEI to give mPEG graft PEI. The mPEG-folate-graft-PEI was synthesized by the reaction of mPEG-PEI with folate pre-activated by EDC/NHS. The obtained copolymers were characterized by $^1H-NMR$ and FT-IR. Gel retardation assay and fluorescence measurement indicated that DNA formed the complexes with the synthesized copolymers above N/P charge ratio 2. The size of complexes was ranging from 100 nm to 300 m. In conclusion, we confirmed that the synthesized copolymer have the possibility as a DNA carrier.

• Journal of the Korean Chemical Society
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• v.24 no.3
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• pp.250-258
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• 1980

Various radicals may add to isonitriles to give imidoyl radcals RN=CR'. This may be also generated via abstraction of imidoyl hydrogen from imine in the following manner: RN=CR' ＋ R"${\cdot}{\rightarrow}$ RN=CR' ＋ R"-H Imidoyl radicals would be stabilized via two pathways, ${\beta}$-cleavage and atom transfer reactions. ${\beta}$-Cleavage may occur in two directions depending upon structure of the radicals. Cyanide transfer and the "so-called" normal ${\beta}$-cleavage are the two modes of ${\beta}$-cleavage. Addition of t-butoxy radical to t-butyl isocyanide 7 generates an imidoyl radical t-Bu-N=C-O-Bu-t, which undergoes ${\beta}$-cleavage to give t-butyl isocyanate and t-butyl radical. Addition of phenyl radical to 7 forms the intermediate radical t-Bu-N=$C-C_6H_5$, which decomposes to give benzonitrile and t-butyl radical. The t-butyl radical generated from the ${\beta}$-cleavage adds to 7 giving the radical t-Bu-N=C-Bu-t, which cleaves only to pivalonitrile and t-butyl radical, inducing radical chain isomerization. Trimethylsilyl radical adds to 7 to give the intermediate t-Bu-N=$C-Si(CH_3)_3$, which collapses to $(CH_3)_3$SiCN and a t-butyl radical.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.465-469
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• 2011

In this study, poly(ethyleneoxide) and poly(ethylene imine) polymer blends containing fumed silica fillers were studied in order to enhance the ion conductivity and interfacial properties. Lithium perchlorate ($LiClO_4$) as a salt, and silica($SiO_2$) as the inorganic filler were introduced into the polymer composite electrolyte composites and the composites were examined to evaluate their ionic conductivity for a possibility test of electrolyte application. As the diameter of semicircle in an impedance test became smaller, ionic conductivity of composite electrolytes had been enhanced by addition of 20 wt% silica filler. However, the conductivity was not greatly changed over 20 wt% content because the silica was sufficiently saturated in the polymer electrolytes. Diffraction peaks of PEO became weaker with the addition of inorganic fillers using XRD analysis. It showed that a crystallinity was proportionally reduced by increasing filler contents. The morphology of composite electrolyte films has been investigated by SEM. The heterogeneous morphology which silica was evenly dispersed by the strong adhesion of PEI was shown at higher contents of silica.

• Journal of the Korean Chemical Society
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• v.47 no.1
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• pp.13-18
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• 2003

The effect of ultrasonic decomposition was introduced to develop a pretreatment method for the analysis of potassium ion in human urine by potentiometry. N-(4’-benzo-15-crown-5)-anthracene-9-imine, which has a good selectivity coefficient for potassium against ammonium, was used as an ion-selective material for the determination of potassium in urine with relatively high concentration of $NH_4{^+}$. Protenis in urine be removed by 85.1% when the sample acidified with 1.0 M $HNO_3$ was preteated for 100 s by sonication. Potential response of the membrane electrode in the pretreated urine had a slope of 54.6(${\pm}0.2,\;n=5$) mV/decade over the linear range of log $[K^+]$=-5~-1(r=0.9997). When an oxidant, $H_2O_2$, was addwd to the urine sonicated with $HNO_3$, the deproteinization increased 10% more than that in case if only $HNO_3$ and then the maximum ratio of ca. 95% was obtained. Moreover, the Nernstian slope for $K^+$ added to the urinary sample increased to 56.7(${\pm}0.1,\;n=3$) mV/decade. When the calibration curves were measured, the slopes did not vary even after the electrode was successively used 20 times with ultrasonic cleaning. The results showed that an ultrasonic pretreatment method provides simplicity in use, reduced treatment time and improved potentiometric characteristics of the membrane as the method effectively removes ca. 95% of proteins in urine.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.23-26
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• 2010

A Schiff base ligand (Z)-N-((Z)-2-(sec-butylimino)-1,2-diphenylethylidene)butan-2-amine was synthesized by condensation of benzil with sec-butyl amine. Complexation of the ligand was carried out with first row transition elements, manganese(II) and nickel(II). Ligand and complexes were characterized by FTIR, elemental analysis and thermogravimetric analysis in solid state and by NMR ($^1H,\;^{13}C$) in solution form. Both the complexes demonstrate good catalytic activity for butadiene oligomerization under mild conditions with methylaluminoxane (MAO) as co-catalyst.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.1985-1989
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• 2013

A simple colorimetric and fluorescent anion sensor 1 based on salicylimine showed a high selectivity and sensitivity for detection of cyanide in aqueous solution. The receptor 1 showed high selectivity toward $CN^-$ ions in a 1:1 stoichiometric manner, which induces a fast color change from colorless to orange and a dramatic enhancement in fluorescence intensity selectively for cyanide anions over other anions. Such selectivity resulted from the nucleophilic addition of $CN^-$ to the carbon atom of an electron-deficient imine group. The sensitivity of the fluorescence-based assay (0.06 ${\mu}M$) is below the 1.9 ${\mu}M$ suggested by the World Health Organization (WHO) as the maximum allowable cyanide concentration in drinking water, capable of being a practical system for the monitoring of $CN^-$ concentrations in aqueous samples.

• Journal of Pharmaceutical Investigation
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• v.41 no.1
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• pp.45-50
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• 2011

Nonclassical pathway of crystallization has been utilized to modify the properties and morphologies of inorganic and organic/inorganic materials. In here, the polymer-directed crystallization method has been applied to the pharmaceutical active ingredient to assess the applicability for as a particle engineering tool. The polymer-directed crystallization was successful to modifying the crystal size, habit and morphology, but it was not effective to discover the novel polymorphs of Sibutramine (SB). SB was selected as a model drug and polyacrylic acid (PAA), polyethylene imine (PEI) and chitosan (CHI) were added as a crystallization pathway modifier. SB was crystallized via drowning crystallization using methanol or ethanol as a solvent and water as a non-solvent. The significant interactions between polymer and the drug were confirmed by measuring the solubility of the drug in presence of polymer during the crystallization. The crystal forms of SB are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and optical microscope (OM). The polymer-directed crystallization seems to be able to modify the crystal properties of pharmaceutical active ingredient, which is critical in determining the bioavailability, processability, and stability.