• 대한화학회지
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• 제53권2호
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• pp.159-165
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• 2009

2-Amino-5-Substituted-1,3,4-Oxadiazoles의 합성은 비분활된 셀에서 포텐셜 전기분해의 제어하에 백금전극의 세미카바존 전기적 산화로부터 수행되었다. 이것은 유기화학 합성분야에서 환경적으로 양호한 방법이다. 아세트산 및 아세트니트릴, 무수용매와 리튬 과염소산염 이 전기적 산화에서 전기분해을 위하여 사용 되어졌다. 생성물은 IR, $^1H$-NMR, $^{13}C$-NMR 그리고 원소분석을 통해 구조분석 하였다.

• 한국응용과학기술학회지
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• 제33권2호
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• pp.255-263
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• 2016

식품부패미생물에 대한 감초추출물의 항균력을 확인하고 유효성분을 분리한 후 그 구조를 확인 하였다. 감초추출물은 대표적인 항균제인 메타중아황산칼륨과 myconazole과 비슷한 항균 활성을 나타내었다. 용매분획을 실시한 결과 chloroform fraction이 가장 항균활성이 높은 것으로 나타났다. 이에 chloroform분획을 silica gel column chromatography를 통해 분리하여 항균활성이 가장 큰 분획물인 KC를 분리하였다. 이 화합물은 ESI-MS 와 $^1H$-NMR, $^{13}C$-NMR 결과로부터 활성물질의 구조를 동정하였으며 그 결과 KC는 (R)-glabridin인 것으로 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.823-826
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• 2013

A low-${\varepsilon}$ solid-state NMR(Nuclear Magnetic Resonance) probe was developed for the spectroscopic analysis of two-dimensional $^{15}N-^1H$ heteronuclear dipolar coupling in dilute membrane proteins oriented in hydrated and dielectrically lossy lipid environments. The system employed a 800 MHz narrow-bore magnet. A solenoid coil strip shield was used to reduce deleterious RF sample heating by minimizing the conservative electric fields generated by the double-tuned resonator at high magnetic fields. The probe's design, construction, and performance in solid-state NMR experiments at high magnetic fields are described here. Such high-resolution solid-state NMR spectroscopic analysis of static oriented samples in hydrated phospholipid bilayers or bicelles could aid the structural analysis of dilute biological membrane proteins.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2007년도 Proceedings of The Convention
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• pp.19-27
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• 2007

An important potential of metabolomics-based approach is the possibility to develop fingerprints of diseases or cellular responses to classes of compounds with known common biological effect. Such fingerprints have the potential to allow classification of disease states or compounds, to provide mechanistic information on cellular perturbations and pathways and to identify biomarkers specific for disease severity and drug efficacy. Metabolic profiles of biological fluids contain a vast array of endogenous metabolites. Changes in those profiles resulting from perturbations of the system can be observed using analytical techniques, such as NMR and MS. $^1H$ NMR was used to generate a molecular fingerprint of serum or urinary sample, and then pattern recognition technique was applied to identity molecular signatures associated with the specific diseases or drug efficiency. Several metabolites that differentiate disease samples from the control were thoroughly characterized by NMR spectroscopy. We investigated the metabolic changes in human normal and clinical samples using $^1H$ NMR. Spectral data were applied to targeted profiling and spectral binning method, and then multivariate statistical data analysis (MVDA) was used to examine in detail the modulation of small molecule candidate biomarkers. We show that targeted profiling produces robust models, generates accurate metabolite concentration data, and provides data that can be used to help understand metabolic differences between healthy and disease population. Such metabolic signatures could provide diagnostic markers for a disease state or biomarkers for drug response phenotypes.

• 한국자기공명학회논문지
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• 제22권2호
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• pp.34-39
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• 2018

The Nuclear Magnetic Resonance (NMR) technique using Dynamic Nuclear Polarization (DNP) procedures is one of the promising techniques that enable overcoming low sensitivity problems in NMR spectroscopy. We constructed an ODNP-NMR system using a commercial benchtop EPR spectrometer. The $^1H$ NMR peak area of water in aqueous solutions of 4-hydroxy-TEMPO was enhanced more than 95 times in the ODNP-NMR experiments. Our signal enhancement results were about 55% of the previously reported result. This could be due to non-uniform microwave power over a sample and unwanted sample heating by microwave. However, this portable ODNP-NMR spectrometer will be eventually useful for site-specific detection with nano-scale spatial resolutions and molecular dynamics studies with significantly improved signal sensitivity.

• 농업과학연구
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• 제35권1호
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• pp.11-17
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• 2008

가시오가피를 실온에서 petroleum ether로 추출한 polyacetylene의 동정하기 위하여 TLC, HPLC, UV spectrum, IR, NMR로 수행하였다. TLC에 전개시킨 결과, polyacetylene 표준품과 동일한 band가 fraction 5에서 확인되었으며, HPLC에서 fraction 5를 분리시킨 결과 retention time이 4.40, 5.36, 6.40분이었다. 이를 UV spectrum에서 확인한 결과, 6.40분의 peak(compound 3)에서 polyacetylenes의 파장인 231.0nm, 239.0nm, 257.0nm을 나타내었다. IR spetrum에서 triple bond $2256cm^{-1}$과 double bond $1654cm^{-1}$의 전형적인 peak를 나타내었으며, $^{13}C$-NMR(400MHz, $CDCl_3$)에서 polyacetylenes 전형적인 64.0, 71.2, 74.2, 80.2ppm은 2개의 triple bond에 의한 peak와 121.89, 133.0ppm에서 internal double bond로 결합된 2개의 peak를 확인 할 수 있었다.

• 분석과학
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• 제18권1호
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• pp.1-4
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• 2005

반응 속도를 조절하기 위하여 유기 첨가제인 아세트산을 사용해 치환된 티타늄 이소프로폭사이드를 합성한 뒤 가수분해 시킨 실리콘(IV)에톡사이드와 반응시켜 $TiO_2-SiO_2$ 분말을 얻었다. 반응 과정 동안의 구조 변화와 특징을 NMR과 FT-IR을 통해서 살펴보았다. 열처리 과정을 거친 분말의 FT-IR 결과로부터 상 분리를 관찰하였다.

• 생약학회지
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• 제44권1호
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• pp.6-9
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• 2013

Two fraxinellone-based hydrogenated derivatives were prepared from fraxinellone, a well-known degraded limonin, via catalytic hydrogenation in the presence of $PtO_2$ in HOAc. Their structures were confirmed as (3S,3aR,3'R)-3a,7-dimethyl-3-(tetrahydrofuran-3-yl)-3a,4,5,6-tetrahydroisobenzofuran-1(3H)-one and (3S,3aR,2'R)-3-((R)-1-hydroxybutan-2-yl)-3a,7-dimethyl-3a,4,5,6-tetrahydroisobenzofuran-1(3H)-one on the basis of 2D NMR assignments. The $^{13}C$ NMR assignments of two quaternary carbons in the ${\alpha}$,${\beta}$-unsaturated carbonyl moiety of ${\gamma}$-butyrolactone core of fraxinellone should be revised.

• 약학회지
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• 제39권1호
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• pp.85-93
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• 1995

Acidic and alkaline hydrolysis of diol-type ginseng saponins produced a new glycoside, (20E)-ginsenoside Rh$_{3}$, and its stereoisomer (20Z)-, which were further subjected to alkaline by drolysis to give their aglycones, (20E)- and (20Z)-3$\beta$, 12$\beta$-dihydroxy-dammar-20(22),24-diene. The ratio of stereoisomeric mixtures was estimated to be ca. 5:1 from intensities of the peaks in $^{1}$H- and $^{13}$C-NMR spectra. The $^{1}$H- and $^{13}$C-NMR signals of ginsenoside Rh$_{3}$, which have remained unclarified, were completely assigned by the extensive application of modern NMR techniques.

• Bulletin of the Korean Chemical Society
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• 제18권9호
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• pp.1002-1006
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• 1997

1H NMR spectra of D2O solutions containing 2,2-dimethylaziridine (1) or 2-methylaziridine (2) and [SiW11COⅡO39]6- (SiW11Co) or [SiW11NiⅡO39]6- (SiW11Ni) exhibit separate signals for the free ligand and the complex, indicating that the ligand exchange is slow on the NMR time scale. Identified are two linkage isomers with the methyl group of 2 at trans or cis position with respect to the metal. The isotropic shifts of 1 and 2 coordinated to SiW11Ni originate mainly from the contact shifts, and they agree reasonably with the relative values reported for similar ligands coordinated to bis(2,4-pentanedionato)nickel(Ⅱ). The isotropic shifts for the SiW11Co complexes were separated into contact and pseudocontact contributions. The pseudocontact shifts show that (χ∥-χ⊥) is positive, while that for the SiW11Co complexes of pyridine derivatives is negative. This result indicates that the ordering of dxy and dxz, dyz orbitals in SiW11Co complexes can be reversed by ligands.