• Applied Biological Chemistry
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• v.47 no.2
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• pp.270-273
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• 2004

Two prenylated flavonoids were isolated from a chloroform extract of the root bark of Cudrania tricuspidata. Both compounds (1, 2) showed antibacterial activity against Gram positive bacteria, Staphylococcus aureus, Bacillus subtilis and Bacillus cereus. Their structures were determined as euchrestaflavanone B (1) and euchrestaflavanone C (2) on the basis of $^1H\;NMR,\;^{13}C\;NMR$ and long-range coupling NMR techniques.

• 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 Ginseng Research
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• v.38 no.3
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• pp.194-202
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• 2014

Background: Ginsenosides, the major ingredients of Panax ginseng, have been studied for many decades in Asian countries as a result of their wide range of pharmacological properties. The less polar ginsenosides, with one or two sugar residues, are not present in nature and are produced during manufacturing processes by methods such as heating, steaming, acid hydrolysis, and enzyme reactions. $^1H$-NMR and $^{13}C$-NMR spectroscopic data for the identification of the less polar ginsenosides are often unavailable or incomplete. Methods: We isolated 21 compounds, including 10 pairs of 20(S) and 20(R) less polar ginsenosides (1-20), and an oleanane-type triterpene (21) from a processed ginseng preparation and obtained complete $^1H$-NMR and $^{13}C$-NMR spectroscopic data for the following compounds, referred to as compounds 1-21 for rapid identification: 20(S)-ginsenosides Rh2 (1), 20(R)-Rh2 (2), 20(S)-Rg3 (3), 20(R)-Rg3 (4), 6'-O-acetyl-20(S)-Rh2 [20(S)-AcetylRh2] (5), 20(R)-AcetylRh2 (6), 25-hydroxy-20(S)-Rh2 (7), 25-hydroxy-20(S)-Rh2 (8), 20(S)-Rh1 (9), 20(R)-Rh1 (10), 20(S)-Rg2 (11), 20(R)-Rg2 (12), 25-hydroxy-20(S)-Rh1 (13), 25-hydroxy-20(R)-Rh1 (14), 20(S)-AcetylRg2 (15), 20(R)-AcetylRg2 (16), Rh4 (17), Rg5 (18), Rk1 (19), 25-hydroxy-Rh4 (20), and oleanolic acid 28-O-b-D-glucopyranoside (21).

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.603-608
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• 2005

The $^1H\;and\;^{13}C$ chemical shifts of flavone and its five derivatives were determined completely using the basic 1D and 2D NMR experiments and molecular modeling. Of the six compounds used for our experiments, the NMR data of three compounds were published previously, but we found that the data of two compounds included wrong assignments. Therefore, we report the corrected data and the complete assignments of NMR data of the other three compounds.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.145-151
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• 2007

To investigate the chemical constituents of Acer tegmentosum, the bark were collected, air-dried and extracted with 70% aqueous acetone. Then it was successively partitioned with n-hexane, $CH_2Cl_2$, EtOAc and $H_2O$. Repeated Sephadex LH-20 column chromatography on the EtOAc soluble fraction gave five phenolic compounds. Their structures were elucidated as (+)-catechin (1), (-)-epi-catechin (2), Q-epicatechin-3-O-gallate (3), gallic acid (4) and 6'-0-galloylsalidroside (5) on the basis of spectroscopic evidences using $^1H-NMR$, $^{13}C-NMR$, 2D-NMR and MS spectroscopy, (-)-epicatechin-3-Ogallate (3), gallic acid (4), 6'-Ogalloylsalidroside (5) have not been reported in this plant yet.

• Korean Journal of Pharmacognosy
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• v.27 no.3
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• pp.207-211
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• 1996

Cumambrin A has been isolated from the dried flowers of Chrysanthemum boreale Makino. The complete $^1H$ and $^{13}C$ NMR assignment of cumambrin A was achieved from two-dimensional $^1H$-$^1H$ COSY and $^{13}C$-$^1H$ COSY spectra with the aid of homonuclear and heteronuclear double resonance experiments. The its structure has been verified by single crystal X-ray diffraction.

• Journal of Sericultural and Entomological Science
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• v.38 no.2
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• pp.180-185
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• 1996

Biosynthesis tracing of the silk fibroin in Bombyx mori silkworm was examined in vivo with isotopic [1-13C] Gly. labeling by nuclear magnetic resonance method. The [1-13C] Gly. labeled silk fibroin yielded very sharp 13C NMR signal in the posterior silk gland as well as in aqueous solution and the amound of [1-13C] Gly. labeled signal in the silkworm increased gradually and rapidly to 5-th day of fifth instar. However, the decomposition or decrease of the [1-13C] Gly. labeled signal occured from 5-th to 9-th day of fifth instar unexpectedly. These findings suggest that a relative amount of ${\alpha}$-helical portion or amorphous silk II portion was formed without any further signal from 6-th day of fifth instar to pupation. Through peak separation of orientation spectrum, between the fiber axis and the molecular bond direction, N-H bond in Bombyx mori silk fiber as well as the orientation distribution around the silk fibroin axis were determined and two kinds of peaks were also obtained from this orientation spectrum.

• Natural Product Sciences
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• v.3 no.1
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• pp.11-13
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• 1997

From the methanolic extract of defatted tender leaf of Camellia sinensis a new 4-hydroxy angular furocoumarin $C_{12}H_8O_5$, m.p. $212^{\circ}C$, was isolated using high-speed counter-current chromatographic technique. The structure of the compound was established as 4-hydroxy-2'-methoxy angular furocoumarin on the basis of physical methods viz. $^1H$ NMR, $^{13}C$ NMR and MS.

• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1244-1248
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• 1998

Ozonolysis reactions of cyclic olefins 1a-c and norbomene In in the presence of trifluoroactophenone 6 provided the corresponding cross-ozonides 7a-c and 7n. Further reactions of ozonides 7a-c and 7n with the independently prepared carbonyl oxide 11 gave diozonides of structure l0a-c and 10n. The ozonolysis of 1methylcyclopentene 12a and 1-methylcyclohexene 12b in the presence of trifluoroactophenone 6 provided exclusively ozonide 15 and 16 derived from capture of carbonyl oxide 13. All of the new ozonides have been isolated as pure substances and characterized by their 1H NMR and 13C NMR spectra.

• Food Science of Animal Resources
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• v.41 no.2
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• pp.312-323
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• 2021

The purpose of this study was to use 1H nuclear magnetic resonance (1H NMR) to quantify taste-active and bioactive compounds in chicken breasts and thighs from Korean native chicken (KNC) [newly developed KNCs (KNC-A, -C, and -D) and commercial KNC-H] and white-semi broiler (WSB) used in Samgye. Further, each breed was differentiated using multivariate analyses, including a machine learning algorithm designed to use metabolic information from each type of chicken obtained using 1H-13C heteronuclear single quantum coherence (2D NMR). Breast meat from KNC-D chickens were superior to those of conventional KNC-H and WSB chickens in terms of both taste-active and bioactive compounds. In the multivariate analysis, meat portions (breast and thigh) and chicken breeds (KNCs and WSB) could be clearly distinguished based on the outcomes of the principal component analysis and partial least square-discriminant analysis (R2=0.945; Q2=0.901). Based on this, we determined the receiver operating characteristic (ROC) curve for each of these components. AUC analysis identified 10 features which could be consistently applied to distinguish between all KNCs and WSB chickens in both breast (0.988) and thigh (1.000) meat without error. Here, both 1H NMR and 2D NMR could successfully quantify various target metabolites which could be used to distinguish between different chicken breeds based on their metabolic profile.