• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.702-706
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• 1995

A major component(compound A) in the ethylacetate fraction exhibited a strong antimicrobial activity was identified by UV, IR, FABMS and NMR. The compound A showed strong absorbance at 209, 259 and 359nm, indicating a flavonoid ring structure. IR spectrum possessed absorbance of OH at 3400∼3300cm-1, ketone at around 1650cm-1, and aromatic C=C at around 1660cm-1. Molecular weight of the compound A calculated as 478 from the information of m/z 479(M＋H)+ and m/z 477(M-H)+ in the FABMS spectrum. Molecular formula of this compound was found to be C22H22O12 from m/z 479.1220(＋3.1mmu for C22H23O12) of HRFABMS spectrum and from 13C-NMR spectrum. 1H-NMR and 13C-NMR spectra of the compound A revealed aromatic proton and benzene rings. Distortionless enhancement by polarization transfer(DEPT) exhibited that the compound A possessed 10 quaternary carbons and 3 substituted benzene rings including a methoxy group substitution. The compound A was identified as isorhamnetin 3-O-β-glucopyranoside by spectrophotometric methods in conjunction with 1H-1H COSY, 1H-13C COSY and HMBC, which revealed a flavone with OH group at 3, 5, 7, and 4' and methoxy group at 3' positions esterified to glucose.

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.356-360
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• 2007

5,7-Diaryl-3,4,6-trihydronaphthalen-2-ones have been synthesized from 3,5-diaryl-cyclohex-2-en-1- ones and methyl vinyl ketone in the presence of sodium ethoxide. The products were characterized by IR, UV-Visible, 1H-NMR, 13C-NMR and mass spectral techniques. To confirm 1H and 13C signals, HSQC spectrum was recorded and analyzed.

• Journal of the Korean Magnetic Resonance Society
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• v.11 no.2
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• pp.64-72
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• 2007

[ $^1H$ ] nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal $(NH_4)_3H(SO_4)_2$. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the $^1H$ NMR MAS spectrum at 340 K. As temperature decreases, the $^1H$ NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of $T_1$ for ammonium and hydrogen-bond protons are similar in the whole range of temperature. $T_1$ of $^1H$ NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then $T_1$ shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and $T_1$ clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.

• Analytical Science and Technology
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• v.7 no.2
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• pp.187-191
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• 1994

A reactive intermediate 1,2-dihydropyridine derivative 2 has been prepared and isolated from the reaction of pyridine with $^tBuLi$ and trimethylchlorosilane in nonpolar condition at low temperature 2 has characterized by $^1H-NMR$ fine structure analysis with SPINX3. The mechanistic information of formation of 2 was obtained from synthesized 2,5-disubstituted pyridine derivatives 3 and 4.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.1
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• pp.29-35
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• 2015

The microscopic dynamics of $CsH_2PO_4$, with two distinct hydrogen bond lengths, are studied by static nuclear magnetic resonance (NMR) and magic angle spinning (MAS) NMR. The proton dynamics of the two crystallographically inequivalent hydrogen sites were discussed in terms of the $^1H$ NMR and $^1H$ MAS NMR spectra. Although the hydrogen bonds have two inequivalent sites, H(1) and H(2), distinct proton dynamics for the two sites were not found. Further, the $^{133}Cs$ spectrum is more or less continuous near $T_{C1}$ (=153 K). Finally, the phase transition mechanism of $T_{C1}$ in $CsH_2PO_4$ is related to the ordering of protons.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.538-545
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• 2001

The ratio of regioisomers in nitration of biphenyl derivatives containing electron-with-drawing group was examined. The ratio of isomers was determined efficiently by quantitative analysis of $^1$H NMR spectrum of product mixture based on $^1$H NMR spectrum of each isomer. Some isomers were isolated after chemical transformation, nitro to amine or carboxylic acid to its ethyl ester, because direct separation was very difficult. To improve the regiselectivity, representative several reaction conditions were tried and the NMR method was applied to determine regioselectivity in nitration of biphenyl derivatives. It was observed that the regioselectivity depend on not only reaction conditions but also position and kind of substituents.

• Journal of the Korean Magnetic Resonance Society
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• v.21 no.4
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• pp.114-118
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• 2017

Here, I report solid state Dynamic Nuclear Polarization (DNP) of $^1H$ nuclear spins at 0.3 T and 4.2 K. The DNP polarizer was developed based on a commercial X-band Electron Spin Resonance (ESR) modified for DNP, in combination with a NMR console and a liquid-Helium cryostat. By detuning magnetic field, DNP spectrum was measured to find the optimal condition. At +3 mT detuned from on-resonance field, $^1H$ NMR signal of 60:40 glycerol/water frozen solution doped with 20 mM perdeuterated-Tempone was amplified 43 times. The $^1H$ spin polarization obtained at 4.2 K is over 3100 times higher than that at 300 K. The width of the DNP spectrum, which is five times broader than ESR spectrum, is inconsistent with solid effect or thermal mixing, and presumably suggests a different DNP mechanism.

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.413-421
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• 1986

Hydrocarbon solution of $Cp_2Zr(CH_3)Cl$ react rapidly with $Na_2Fe(CO)_4$ (1/2 equiv.) to yield $[Cp_2Zr(CH_3)]_2Fe(CO)_4$ and NaCl. The more soluble metal-metal bonded complex $[Cp_2ZrC_8H_{17}]_2Fe(CO)_2$ has also been prepared through the reaction of $Cp_2Zr(C_8H_{17})BF_4$ and $Na_2Fe(CO)_4 (1/2 equiv.). The complexes were characterized by IR, $^1H$ NMR, ^{13}C$ NMR, and elemental analysis. The infrared spectrum of $[Cp_2ZrR]_2Fe(CO)_4$ shows four bands, which is indicative of a cis-structure. The $^{13}C$ NMR spectrum provides evidence for the cis-structure.

• Journal of Life Science
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• v.9 no.2
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• pp.207-211
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• 1999

Biologically active compounds in Polygonatum sibiricum were extracted using organic solvents as hexane, CHCl$_3$, n-butanol corresponding each component. Compound I was purified from hexane layer and the chemical structure of compound I was characterized using 1H-NMR, 13C-NMR, DEPT135, COSY, HMQC, HMBC spectrum and MS-spectrum. Consequently, the chemical structure of compound I was determined as 9,12-(9E,l2E)-octade cadienoic acid.

• 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.