• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2001.02a
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• pp.17-17
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• 2001

• Macromolecular Research
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• v.13 no.5
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• pp.373-384
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• 2005

Novel pH-sensitive moieties containing an s-triazine ring were synthesized with sulfonamide and secondary amino groups. The synthesized pH-sensitive moieties were used for the synthesis of a pH-sensitive amphiphilic ABA triblock copolymer. The pH-sensitive triblock copolymer was composed of diblock copolymers, methoxy poly(ethylene glycol)-poly ($\varepsilon$-caprolactone-co-D,L-lactide) (MPEG-PCLA), and pH-sensitive moiety. These copolymers could be dissolved molecularly in both acidic and basic aqueous media at room temperature due to secondary amino and sulfonamide groups. The synthesized s-triazine rings containing pH-sensitive compounds were characterized by ${^1}H-NMR,\;{^13}C-NMR$, and LC/MSD spectral data. The synthesized diblock and triblock copolymers were also characterized by ${^1}H-NMR$ and GPC analyses. The critical micelle concentrations at various pH conditions were determined by fluorescence technique using pyrene as a probe. Furthermore, the micellization and demicellization study of the triblock copolymer was done with pH-sensitive groups. The sensitivity towards pH change was further established by acid-base titration.

• Journal of Plant Biotechnology
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• v.36 no.1
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• pp.64-67
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• 2009

In order to identify secondary metabolites, the root of Brassica rapa was extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and $H_2O$. From the EtOAc and n-BuOH fractions, four secondary metabolites were isolated through the repeated silica gel and octadecyl silica gel (ODS) column chromatographies. From the result of spectroscopic data including NMR and MS, the chemical structures of the compounds were determined as 4-(methoxymethyl)phenol (1), ${\alpha}$-methoxy-2,5-furandimethanol (2), phenyl-${\beta}$-D-glucopyranoside (3), and 2-phenylethyl-${\beta}$-D-glucopyranoside (4). They were isolated for the first time from Brassica rapa.

• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1467-1472
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• 2013

Metabolomics is a field that studies systematic dynamics and secretion of metabolites from cells to understand biological pathways based on metabolite changes. The metabolic profiling of intact human colorectal tissues was performed using high-resolution magic angle spinning (HR-MAS) NMR spectroscopy, which was unnecessary to extract metabolites from tissues. We used two different groups of samples, which were defined as normal and cancer, from 9 patients with colorectal cancer and investigated the samples in NMR experiments with a water suppression pulse sequence. We applied target profiling and multivariative statistical analysis to the analyzed 1D NMR spectra to identify the metabolites and discriminate between normal and cancer tissues. Cancer tissue showed higher levels of arginine, betaine, glutamate, lysine, taurine and lower levels of glutamine, hypoxanthine, isoleucine, lactate, methionine, pyruvate, tyrosine relative to normal tissue. In the OPLS-DA (orthogonal partial least square discriminant analysis), the score plot showed good separation between the normal and cancer groups. These results suggest that metabolic profiling of colorectal cancer could provide new biomarkers.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.304-308
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• 1996

The major color component of a Korean pigmented rice (Oeyza sativa var. Suwon 415) was purified with Amberlite XAD-7 column and preparative paper chromatography. The purified pigment was determined as anthocyanin by paper chromatography, UV/Vis and NMR spectroscopy. The $\lambda_{max}$ of the Purified anthocyanin on UV/Vis spectrum were 529 nm and 281 nm. The $A_{440}/A_{529}$ value of the purified anthocyanin was 23% suggesting the presence of 3-glycosidic structure. The aglycone from acid hydrolysis showed bathochromic shift (18 nm) in the presence of $AlCl_3$ indicating that the anthocyanidin contained free adjacent hydroxyl groups such as cyanidin, delphinidin, petunidin or luteolinidin. The sugar moiety obtained from acid hydrolysis was determined as glucose by paper chromatography. The NMR spectra showed that the aglycone was cyanidin and the sugar was ${\beta}-D-glucopyranose$. Thus, the chemical structure of the purified anthocyanin was identified as cyanidin $3-O-{\beta}-D-glucopyranoside$.

• Journal of the Korean Magnetic Resonance Society
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• v.15 no.2
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• pp.128-136
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• 2011

A new sesterterpenoid, phorbaketal derivative, was isolated from the marine sponge Phorbas species. Its planar structures was completely determined from a combination of extensive 1D and 2D NMR experiments and MS data, and also the stereochemistry on the chiral centers were established by the ROESY experiment and the comparison with the $^1H$ and $^{13}C$ chemical shifts of the known phorbaketal compounds. This compound 1 moderately showed cytotoxicity effect against hepatoma cancer HepG2 cell.

• Bulletin of the Korean Chemical Society
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• v.15 no.8
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• pp.673-679
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• 1994

$^1H$ NMR spectra of imidazole, 2-and 4(5)-methylimidazole, histamine, L-histidine, L-histidine methyl ester, N${\alpha}$-acetyl-L-histidine, and L-carnosine coordinated to the paramagnetic undecatungstocobalto(II)silicate ($SiW_{11}Co$) and undecatungstonickelo(II)silicate ($SiW_{11}Ni$) anions are reported. For these complexes the ligand exchange is slow on the NMR time scale and the pure resonance lines of the free ligand and the complexes have been observed separately at room temperature. Two different complexes are formed, depending upon which nitrogen atom of the imidazole ring is coordinated to the cobalt or nickel ion of $SiW_{11}M$. Thus the NMR spectrum of a $D_2O$ solution containing a ligand and $SiW_{11}M$ consists of three sets of lines originating from the free ligand and two complexes. All NMR lines of the $SiW_{11}Co$ complexes have been assigned unequivocally using the saturation transfer technique. The temperature dependence of some spectra are also reported. The NMR spectra of some complexes show that the internal rotation of the substituent on the imidazole ring is hampered by the heteropolyanion moiety even at room temperature.

• Natural Product Sciences
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• v.6 no.2
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• pp.82-85
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• 2000

The aqueous ethanolic whole plant extract of Rosa arabica was found to contain the new natural dimeric phenolic compound, ellagic acid 3,3'-dimethyl ether $4-O-{\alpha}-rhamnopyranoside$, 9, along with ten known phenolic metabolites (1-8, 10 and 11). Structures of all compounds (1-11) were established by routine methods of analysis and confirmed by FAB-MS, $^1H\;and\;^{13}C$ NMR spectral analysis.

• Journal of the Korean Chemical Society
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• v.54 no.4
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• pp.429-436
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• 2010

A series of some biologically active halogenopurines were synthesized from commercially available guanine (1). The reaction of guanine with acetic anhydride yielded 2,9-diacetylguanine (2-1) by acetylation reaction. Further treatment of 2-1 with $POCl_3$ by PEG-2000 phase transfer catalysis furnished the important compound 3a, then 2-amino-6-halogenopurines (3b-d) were obtained through chlorine-exchange halogenations between KX and 3a by TPPB phase transfer catalyst. Further, 2-halogenopurines (2-2a-d, 4-2a-d, 5a-d) were efficiently prepared from 2-amino-6-substituted purines (1, 3a, 4-1) via a diazotization catalyzed by their corresponding CuX, and some new compounds 2-2a, 2-2c, 2-2d, 4-2c, 4-2d, 5b, 5c and 5d have been discovered. The structures of synthesized compounds were mainly established on the basis of their elemental analysis, $^1H$ NMR, as well as their mass spectral data. All the title compounds were screened for their antifungal activities, and some of the compounds showed promising activity.

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.63-67
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• 1998

The synthesis and characterization of the monomeric group 13 heterocyclic thiosemicarbazone complexes $Me_2M[SC_4H_3CHNNC(S)SCH_3]$ (M=Al (2), Ga (3)) are described. Compounds 2-3 were prepared using $MMe_3$ (M=Al, Ga) in toluene with 2-thiophenecarboxaldehyde-S-methyldithiocarbazat e under anaerobic conditions. These complexes have been characterized by $^1H\;NMR,\; ^{13}C\; NMR$, elemental analyses, and single-crystal X-ray diffraction. 2 crystallizes in the monoclinic space group $P2_1/c$ with unit cell parameters a=10.2930(5) Å, b=18.564 (1) Å, c=7.3812(6) Å, V=1347.9(2) Å3, $D_{calc}=1.342\; gcm^{-3}$ for Z=4, 9281 reflections with $I_o<3{\sigma}\;(I_o),$ R1=0.0500 and wR2=0.0526. 3 crystalizes in the orthorhombic space group $P_{bca}$ with unit cell parameters a=13.340(3) Å, b=19.9070(5) Å, c=11.3690(2) Å, $V=2673.88(9)\;{\AA}^3$, $D_{calc}=1.511\; gcm^{-3}$ for Z=8, 17004 reflections with $I_o>3{\sigma}\;(I_o),$, R1=0.0480 and wR2=0.0524. Compound 3 is a monomeric gallium compound with a weak interaction between the pendant thiophene and the gallium center.