• Proceedings of the PSK Conference
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• 2002.10a
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• pp.351.2-351.2
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• 2002

We have previously reported the synthesis and cytotoxic activities of a series of azaanthraquinone derivatives on the model of doxorubicin(Dox). Dox is known to intercalate into DNA and to inhibit topoisomerase II activity. But in the case of Quinone compounds like Dox. its use is limited because of systemic toxicities. primarily cardiotoxicity and myelosuppression. In this study. we describe the synthesis of benzoquinoxaline derivatives as DACA analogue. DACA has a neutral chromophore and acridine moiety and posions both topoisomerases I and ll with DNA intercalating activity. In order to delineate the SAR of benzoquinoxaline derivatives. an effcient sythetic rout to the target compounds without quinone group. Various attempted removal of quinone from benzoquinoxlinedione was unsuccessful. Diels-Alder rout applied for the synthesis of the target compounds will be discussed.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.174.1-174.1
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• 2003

We have previously reported the synthesis and cytotoxic activities of a series of azaanthraquinone derivatives using doxorubicin as a lead compound. Doxorubicin is known to intercalate into DNA and to inhibit topoisomerase II activity. But in the case of quinone compounds like Dox, its use is limited because of systemic toxicities, primarily cardiotoxicity and myelosuppression. In this study, we discuss the synthesis of isoindolobenzoquinoxaline derivatives. The quinone group of the azaanthraquinone derivatives were removed in the target compounds. (omitted)

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1323-1328
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• 2006

Mesoporous nickel intercalated aluminosilicate nanohybrid has been synthesized through a recombination reaction between the colloidal suspension of exfoliated montmorillonite nanosheets and aqueous nickel acetate solution. According to powder X-ray diffraction and field emission-scanning electron microscopic analyses, the intercalation of nickel species expands significantly the basal spacing of the host montmorillonite clay and the crystallites of the intercalation compound are assembled to form a house-of-card structure. $N_2$ adsorption-desorption isotherm measurements with BJH pore analyses clearly demonstrated that the porosity of the intercalate originates mainly from mesopores (diameter $\sim50\;\AA$) formed by the house-of-card type stacking of clay crystallites. From FT-IR and X-ray absorption spectroscopic analyses, it becomes certain that intercalated nickel ion is stabilized in an isolated $NiO_6$ octahedral unit. The present mesoporous intercalation compound is expected to be applicable as efficient catalysts or absorbents.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.435-441
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• 2010

We report the preparation and characterization of a new and water soluble complex of palladium(II) with 1,10- phenanthroline and butyldithiocarbamate ligands. This compound has been studied through spectroscopic techniques, $^1H$ NMR, IR, electronic spectra and elemental analysis and conductivity measurements. The complex shows 50% cytotoxic concentration ($Ic_{50}$) value against chronic myelogenous leukemia cell line, K562, much lower than that of cisplatin. Thus the mode of binding of this complex to calf thymus DNA have been extensively investigated by isothermal titration UV-visible spectrophotometry, fluorescence, gel filteration and other methods. UV-visible studies show that the complex exhibits cooperative binding with DNA and remarkably denatures the DNA at extremely low concentration ($~13\;{\mu}M$). Fluorescence studies indicate that the complex intercalate into DNA. Gel filtration studies suggest that the binding of Pd(II) complex with DNA is strong enough that it does not readily break. In these interaction studies, several thermodynamic and binding parameters are also determined which may reflect the mechanism of action of this type of compound with DNA.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.125-128
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• 2001

In this wort, the $Na^+-MMT$ has organically modified with silane intercalant to prepare the polymer/clay nanocomposites. The pH. X-ray diffraction (XRD), and contact angles were used to analyze the surface properties of clay and the exfoliation phenomenon of clay interlayer, The mechanical interfacial properties of epoxy/clay nanocomposites were investigated by three-point bending test. From the experimental results. the surface modification made by silane intercalant on clay surface leads to an increase of distance of silicate layers, surface acid value. and electron acceptor parameter of organoclay. The treatments are also necessary and useful for epoxy to intercalate into the interlayer by interacting of electron donor-accepter between basic epoxy and clay surface. The mechanical interfacial properties of the nanocomposites was improved by the presence of dispersed clay nanolayer containing low content of organoclay in comparison with the conventional, which increase the interfacial adhesion between dispersed clay and epoxy resins.

• Journal of the Korean Chemical Society
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• v.38 no.1
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• pp.8-12
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• 1994

The structure-activity studies are described for the photoreaction of naturally occuring psoralen with thymine. Thymine <> psoralen <> thymine photodiadducts from DNA is studied as a model for the charge transfer interaction by the semiempirical methods (PM3-CI-UHF, etc.). The relative structural activities of psoralen, and photoadducts are analyzed in terms of their differing abilities of psoralen and photoadducts are investigated both with regard to their abilities to complex and to intercalate with thymine base. The photoadducts were inferred to be a trans-anti Psoralen(3,4) <> Thymine(5,6) and cis-anti Thymine(5,6) <> (4',5')Psoralen(3,4) <> Thymine.

• Carbon letters
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• v.8 no.4
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• pp.285-291
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• 2007

Carbon materials of various morphologies were synthesized by pyrolysis of Soap-nut seeds (Sapindus mukorossi), Jack Fruit seeds (Artocarpus heterophyllus), Date-seeds (Phoenix dactylifera), Neem seeds (Azadirachta indica), Tea leaves (Ehretia microphylla), Bamboo stem (Bambusa bambus) and Coconut fiber (Cocos nucifera), without using any catalyst. Carbon materials thus formed were characterized by SEM XRD and Raman. Carbon thus synthesized varied in size (in ${\mu}m$) but all showed highly porous morphology. These carbon materials were utilized as the anode in Lithium secondary battery. Amongst the various precursors, carbon fibers obtained from Soap-nut seeds (Sapindus mukorossi) and Bamboo stem (Bambusa bambus), even after $100^{th}$ cycles, showed the highest capacity of 130.29 mAh/g and 92.74 mAh/g respectively. Morphology, surface areas and porosity of carbon materials obtained from these precursors were analyzed to provide interpretation for their capacity to intercalate lithium. From the Raman studies it is concluded that graphitic nature of carbon materials assist in the intercalation of lithium. Size of cavity (or pore size of channels type structure) present in carbon materials were found to facilitate the intercalation of lithium.

• Macromolecular Research
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• v.8 no.2
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• pp.95-101
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• 2000

Clay/poly(styrene-co-acrylonitrile) copolymer (SAN) hybrids have been prepared by simple meltmixing of two components, SAN and organophilic clays with a twin screw extruder. Effects of intercalant on the dispersibility of silicate layers in clay-dispersed nanocomposite were studied by using five different organophilic clays modified with the intercalants of different chemical structures and different fractions of intercalant. The dispersibility of 10-$\AA$-thick silicate layers of clay in the hybrid was investigated by using an X-ray diffractometer and a transmission electron microscope. It was found that if the fraction of intercalant in the organophilic clay becomes too high, SAN is difficult to intercalate into the inter-gallery of silicate layers in the hybrid prepared at 180$\^{C}$, and thus the hybrid shows poor dispersibility of silicate layers. The flexural modulus of the hybrid increases as the dispersibility of silicate layers in the hybrid increases.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.1-6
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• 2010

The purpose of this study is to synthesize the radio fluorine labelled isoquinoline salt derivative as new radiopharmaceutical for imaging tumors using positron emission tomography (PET). The planarity of isoquinoline allows to inhibit topoisomerase or intercalate between adjacent DNA base pairs, which result in producing double strand breaks in the DNA and a cell death. Therefore, the isoquinoline has seemed to have a potential anticancer activity. In order to obtain 2-(5-[$^{18}F$]fluoropentylisoquinolinium salt with good radiochemical yield, tosylated precursors have been synthesized. The labelling reaction was carried out for 30 minute in HMPA at $120^{\circ}C$. The radiochemical yield was about 50~60%.

• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1799-1805
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• 2019

Doxorubicin (DOX) is one of the most effective anticancer agents used for the treatment of multiple cancers; however, its use is limited by its short half-life and adverse drug reactions, especially cardiotoxicity. In this study, we found that the conjugate of DOX with APTA12 (Gemcitabine incorporated G-quadruplex aptamer) was significantly more cancer selective and cytotoxic than DOX. The conjugate had an affinity for nucleolin, with higher uptake and retention into the cancer cells than those of DOX. Further, it was localized to the nucleus, which is the target site of DOX. Owing to its mechanism of action, DOX has the ability to intercalate into the nucleotides thus making it a suitable drug to form a conjugate with cancer selective aptamers such as APTA12. The conjugation can lead to selectively accumulate in the cancer cells thus decreasing its potential nonspecific as well as cardiotoxic side effects. The aim of this study was to prepare a conjugate of DOX with APTA12 and assess the chemotherapeutic properties of the conjugate specific to cancer cells. The DOX-APTA12 conjugate was prepared by incubation and its cytotoxicity in MCF-10A (non-cancerous mammary cells) and MDA-MB-231 (breast cancer cells) was assessed. The results indicate that DOX-APTA12 conjugate is a potential option for chemotherapy especially for nucleolin expressing breast cancer with reduced doxorubicin associated side effects.