• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.961-965
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• 1997

1H NMR spectra of 3,3-dimethylpiperidine (1) at -70 to 30 ℃ exhibit gradual change from slow to rapid exchange between two alternate chair forms. The exchange rate constant was determined as a function of temperature by simulating the line shape of the signal from the two methyl groups using the modified Bloch equations. The resulting free energy of activation is ΔG* = 44.4±1.9 kJ mol-1 at 298 K. The 1H NMR spectrum of a D2O or dimethylsulfoxide-d6 (DMSO-d6) solution containing 1 and [SiW11CoⅡO39]6- exhibits separate signals for the free ligand and the complex, indicating that the ligand exchange is slow on the NMR time scale. In D2O the piperidine ring is frozen as a chair form even at room temperature with the cobalt ion bonded to the axial position of the nitrogen atom. When DMSO-d6 is added to the D2O solution, the NMR spectral change suggests that a rapid exchange occurs between the chair form and another conformer. It is proposed that the conformation of ^b1^b coordinated to [SiW11CoⅡO39]6- in DMSO-d6 is close to a twist form.

• Archives of Pharmacal Research
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• v.17 no.4
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• pp.284-286
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• 1994

A guaian type sesquiterpene, torilin, was isolated from the hexane extract of the fruits of Torilis japonica. The $^1H{\;}and{\;}^{13}C-sinals$ of this compound have been fully assigned utilizing $^1H-^1H$ COSY, HMQC, and HMBC experiments.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.344-347
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• 2007

The aerial parts of Lespedeza cuneata were collected, air-dried and extracted with 95% aqueous EtOH. Then it was successively partitioned with n-hexane, $CH_2Cl_2$, EtOAc and $H_2O$. Repeated Sephadex LH-20 column chromatography on the EtOAc- and $H_2O-soluble$ fractions gave four compounds. Their structures were elucidated as quercetin (1), kaempferol (2), desmodin (3) and homoadonivernith (4) on the basis of spectroscopic evidences such as $^{1}H-NMR$, $^{13}C-NMR$, 2D-NMR and MS spectrum. Desmodin (3) and homoadonivernith (4) have not been reported from this plant so far.

• Journal of the Korean Chemical Society
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• v.39 no.7
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• pp.564-571
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• 1995

5-Amino-2H-1,2,4-thiadiazoline-3-one has been prepared from 2-thiobiuret through a oxidative cyclization under basic hydrogen peroxide condition. Lactam-lactim tautomerism of 5-amino-2H-1,2,4-thiadiazoline-3-one has been examined by spectroscopic methods and ab initio molecular orbital calculation. These results were shown that 5-amino-2H-1,2,4-thiadiazoline-3-one exists as lactam form. Reaction conditions for alkylating 5-amino-2H-1,2,4-thiadiazoline-3-one with alkyl halides in the presence of various bases were studied in DMF and $H_2O$-THF two phase system. $Li_2CO_3$ base in DMF method gave best result in this investigation. The alkylation has been taken place at N-2 position. The identification of the product is confirmed by spectral data of IR, $^1H$ NMR and $^13C$ NMR and the comparison of authentic sample, 5-amino-2-methyl-1,2,4-thiadiazolidine-3-one, obtained from the oxidative cyclization of 5-methyl-2-thiobiuret.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.179-179
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• 1994

새로운 항생물질을 개발하기 위하여 토양으로부터 분리한 균주를 액체 및 고체배지에서 배양하여 여러 검정균에 대하여 종이디스크법으로 항균효력을 조사하였다. 그 결과 (+), G(-), fungi 등에 강한 항균 효력을 보인 토양균 SNUS 8810-43과 Mycobacterium, fungi에 항균력을 보인 토양균 SNUS 8810-129를 선택하여 각각의 배양액에서 항생물질을 분리하고, 분리한 항생물질의 구조를 규명하고자 하였다. 토양균 SNUS 8810-43의 배양액으로부터 항생물질을 분리하기 위하여 양이온 교환 수지 관 크로마토그래피와 셀룰로오스 관 크로마토그래피를 수행하여 시료 JJH-II-46-43을 얻었다. 시료 JJH-II-46-43의 IR, $^1$H-NMR, $^{13}$C-NMR, $^1$H-$^1$H COSY, $^1$H-$^{13}$C COSY, FAB-MS 스펙트럼을 얻어 분리한 항생물질의 구조를 분석하여 이 항생물질의 구조가 N-methylstreptothricin과 동일하다는 것을 확인하였다. Mycobacterium smegmatis에 강한 활성을 나타내는 물질을 토양균 SNUS 8810-129로 부터 분리하였다. 토양균 SNUS 8810-129를 배양한 V-8 아가판을 메탄올로 추출하여 이를 실리카겔 관 크로마토그래피와 preparative TLC로 시료 LCH-IV-17B, LCH-III-387을 얻었다. 시료LCH-IV-l7B, LCH-III-387의 $^1$H-NMR, $^{13}$C-NMR, FAB-MS, CI-MS, IR등의 스펙트럼을 얻어 분리한 항생물질의 구조를 분석하여 이 항생물질이 glycolipid계 항생물질이라는 것을 알았다. $^{13}$C-NMR 상의 자료와 화학적인 방법으로 구성당을 조사한 결과 이 항생물질을 이루고있는 당은 rhamnose 임을 알았다. 또 이 항생물질을 구성하는 지방산은 화학적인 방법과 MS 스펙트럼, $^{13}$C-NMR 스펙트럼으로부터 hydroxydecanoic acid인 것으로 확인되었다. 항생물질 LCH-III-387와 항생물질 LCH-IV-l7B는 각각 rhamnose를 1, 2개 포함하고 있는 것으로 확인되었다. 그리고 동일한 탄소수의 지방산을 가지고 있는 것으로 생각되었다. 이들 항생물질을 이루는 구성당과 지방산간의 정확한 연결및 구조, 생리활성에 관한 연구는 계속 수행중에 있다.

• Korean Journal of Crystallography
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• v.12 no.3
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• pp.137-140
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• 2001

Compound PdCl₂(Phc≡N)₂(1) reacted with 2,6-diisopropylaniline to give trans-[Pd(NH₂-C/sub 6/-H₃-2, 6-i-Pr₂)₂Cl₂] (2). Compound 2 was characterized by spectroscopy (¹H-NMR, /sup 13/C-NMR, and IR) and X-ray diffraction. Crystallographic data for 2: monoclinic space group P2₁/n, a=13.532(3) Å, b=5.749(1) Å, c=17.880(4)Å, β=103.84(2)°, Z=2, R(wR₂)=0.0466(0.1226).

• Analytical Science and Technology
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• v.13 no.1
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• pp.127-129
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• 2000

The $^2H$ NMR analysis was used to determine the relative deuterium contents at the position of methyl and methylene in ethyl alcohols. Four different liquors manufactured in Korea clearly showed different R values from those of foreign liquors. These R values for the Korean liquors could be used to distinguish adulteration.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1682-1687
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• 2007

The differences in the nonvolatile metabolites of pine-mushrooms (Tricholoma matsutake Sing.) according to different parts and heating times were analyzed by applying principal component analysis (PCA) to $^1H$ nuclear magnetic resonance (NMR) spectroscopy data. The $^1H$ NMR spectra and PCA enabled the differences of nonvolatile metabolites among mushroom samples to be clearly observed. The two parts of mushrooms could be easily discriminated based on PC 1, and could be separated according to different heattreated times based on PC 3. The major peaks in the $^1H$ NMR spectra that contributed to differences among mushroom samples were assigned to trehalose, succinic acid, choline, leucine/isoleucine, and alanine. The content of trehalose was higher in the pileus than in the stipe of all mushroom samples, whereas succinic acid, choline, and leucine/isoleucine were the main components in the stipe. Heating resulted in significant losses of alanine and leucine/isoleucine, whereas succinic acid, choline, and trehalose were the most abundant components in mushrooms heat-treated for 3 min and 5 min, respectively.

• Food Science of Animal Resources
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• v.39 no.1
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• pp.1-12
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• 2019

The objective of this study was to establish an optimized 1D $^1H$ quantitative nuclear magnetic resonance (qNMR) analytical method for analyzing polar metabolites in meat. Three extraction solutions [0.6 M perchloric acid, 10 mM phosphate buffer, water/methanol (1:1)], three reconstitution buffers [20 mM 3-morpholinopropane-1-sulfonic acid, 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid, phosphate buffer], and two pulse programs (zg30, noesypr1d) were evaluated. Extraction with 0.6 M perchloric acid and 20 mM phosphate resulted in a stable baseline and no additional overlap for quantifying polar metabolites in chicken breast. In qNMR analysis, zg30 pulse program (without water-suppression) showed smaller relative standard deviation (RSD) and faster running time than noesypr1d (water-suppression). High-performance liquid chromatography was compared with qNMR analyses to validate accuracy. The zg30 pulse program showed good accuracy and lower RSD. The optimized qNMR method was able to apply for beef and pork samples. Thus, an optimized 1D $^1H$ qNMR method for meat metabolomics was established.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.539-545
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• 2012

3-(2-benzotriazolovinyl)thiophene (BVT) was synthesized by the connection of the thiophene with the electron-withdrawing group, benzotriazole, through the vinylene. Its structure was confirmed by FT-IR, $^1H$-NMR, $^{13}C$-NMR and 2D hetero-cosy spectroscopy. Both BVT and 3-octylthiophene (OT) were copolymerized and showed an average molecular weight of 12000 (PDI 2.67) and 15000 (PDI 2.55), respectively. The copolymers were dissolved in the organic solvent such as chloroform, THF, TCE, etc. The mole ratios of BVT and OT in the synthesized copolymers were confirmed as 1 : 1.8 and 1 : 2.8 from $^1H$-NMR spectra. The UV-vis maximum absorption of copolymers appeared at the wavelength of 470 nm and 465 nm and the photoluminescence at ${\lambda}_{max}$ = 662 nm and 641 nm correspond to red-orange light. The band gaps of copolymers at 1.96 eV and 2.02 eV were found to be higher than those of poly(3-octylthiophene). The HOMO energy levels of the copolymers decreased overall in comparison with those of poly(3-octylthiophene), but the overall LUMO energy level increased.