• YAKHAK HOEJI
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• v.37 no.5
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• pp.476-482
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• 1993

For the investigation of medicinal resources in Crataegus species, the present study was carried out to evaluate the pharmaco-constituents in the leaves of Crataegus Pinnatifida var. psilosa (Rosaceae). Fruits has folk medicine in Korea. From the $Et_{2}$O fraction of MeOH extract, a new compound, apigenin-8-C-(6"-acetyl)-$\beta$-D-glucopyranoside, named psilosin and three known compounds, ursolic acid, phytosterol complex and (-)-epicatechin were isolated and identified on the basis of their physico-chemical properties and spectroscopic evidences (UN, IR, NMR and mass etc.) in comparison with authentics, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.1
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• pp.76-79
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• 1996

생강나무 (Libdera obtusiloba BL.)의 페놀성 화합물들을 분리하기 위하여 잎고 줄기의 MeOH 엑스로부터 계통 분획한 EtOAc 분획물은 silica gel column chro-matography로 분리하여 2종의 화합물을 얻었다. IR, UV,$^1H-NMR$, $^13C-NMR$ 등의 분석을 행하여 화학구조를 밝힌 결과 이들 화합물의 화학구조는 잎에서 $quer-cetin-3-O-\alpha-L-rhamnopyranoside(quercitrin),$ 줄기에서는 quercetin $3-O-\beta-D-galactoyranoside(hyperoside)로$ 각각 결정하였다. 이 화합물들은 생강나무에서 처음으로 분리하였다.

• Journal of Life Science
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• v.11 no.1
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• pp.93-96
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• 2001

n-BuOH fraction obtained from MeOH extracts of Allium monanthum was applied to repeated silica gel column chromatographies to give a glycosylglyceride. The chemical structure of the compound was determined to be 1-O-linolenoyl-2-O-linolenoyl-3-O-$\beta$-D-galactopyranosyl-누-glycerol on the basis of NMR data and by the adaptation of chemical methods.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1539-1542
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• 2011

The aminolysis of O-methyl S-aryl thiocarbonates with benzylamines are studied in acetonitrile at -45.0$^{\circ}C$. The ${\beta}_X$(${\beta}_{nuc}$) values are in the range 0.62-0.80 with a negative cross-interaction constant, ${\rho}_{XZ}$ = -0.42, which are interpreted to indicate a concerted mechanism. The kinetic isotope effects involving deuterated benzylamine nucleophiles ($XC_6H_4CH_2ND_2$) are large, $k_H/k_D$ = 1.29-1.75, suggesting that the N-H(D) bond is partially broken in the transition state by forming a hydrogen-bonded four-center cyclic structure. The concerted mechanism is enforced by the strong push provided by the MeO group which enhances the nucleofugalities of both benzylamine and arenethiolate from the putative zwitterionic tetrahedral intermediate.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1741-1744
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• 2013

A new polymeric catalyst was prepared by supporting $GaCl_3$ on cross-linked polyvinylpyrrolidone ($GaCl_3$/PVP). This catalyst was employed for efficient and regioselective ring-opening reaction of epoxides by various alcohols under solvent-free conditions at room temperature. In our procedure, this heterogeneous catalyst was used at neutral and mild reaction conditions to afford high yields of ${\beta}$-alkoxy alcohols. Also, regioselective conversion of epoxides to ${\beta}$-azidohydrines was accomplished by sodium azide in MeOH in the presence of $GaCl_3$/PVP at room temperature. $GaCl_3$/PVP is a non-hygroscopic and recoverable catalyst and is easily separated from reaction mixture by a simple filtration and re-used repeatedly. Also, this catalyst has good handling and can be stored for long time without any reducing of its reactivity.

• Korean Journal of Pharmacognosy
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• v.25 no.3
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• pp.214-220
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• 1994

From the Viticis Fructus n-hydrocarbons, ${\beta}-sitosterol$ $3-O-{\beta}-_D-glucoside$ and hesperidin along with the known polyoxygenated flavonoids such as vitexicarpin, artemetin and luteolin, and vanillic acid were isolated and identified by means of spectroscopic methods. HPLC analysis of the flavonoid components from the MeOH extract was established. Phytochemical analyses of the domestic plant sample and the imported ones were conducted and the flavonoid compositions of the domestic samples were greatly different from those of the imported ones.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.967-971
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• 1998

KOMAC (KOrea Multi-purpose Accelerator Complex) is the 1 Gev, 20 ㎃ proton linac. The superconducting linac for the high energy part acceleration from 100 MeV to 1 GeV is selected as a main candidate. As is well known, the superconducting linac has advantages for high current, high energy acceleration such as a large bore size, short accelerator length, and the RF efficiency. In this energy, the velocity of proton increases from $\beta$=0.87. For the design and fabrication simplicity, the cavity $\beta$ stages are divided into 3 parts. The maximum electric field in the cavity is designed below 20 ㎹/m. In this paper the design concepts and guides for this superconducting linac are introduced.

• Korean Journal of Pharmacognosy
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• v.34 no.1 s.132
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• pp.28-32
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• 2003

In order to search for the anti-HIV agents from natural products, eighty MeOH extracts of medicinal plants were applied to a syncytia formation inhibition assay which is based on the interaction between the HIV-1 envelope glycoprotein gp120/gp41 and the cellular membrane protein CD4 of T lymphocytes. Among them, Ailanthus altissima showed a potent virus-cell fusion inhibitory activity. Repeated column chromatoghaphy of the methylene chloride fraction of A. altissima afforded compounds 1$({\beta}-sitosterol-3-O-{\beta}-D-glucoside)$, 2(tetramethoxycoumarin), and 3(ocotillone). Virus-cell fusion inhibitory activity of compound 3(ocotillone) was $70.76{\pm}4.09%$ at the concentration of $100\;{\mu}g/ml$.

• Korean Journal of Pharmacognosy
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• v.21 no.2
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• pp.148-152
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• 1990

Seven flavonol glycosides from the EtOAc fraction of Ginkgo biloba leaves were identified by high performance liquid chromatography. Separation by reversed phase chromatography on $Lichrosorb^{\circledR}$ RP-18 column was achieved by isocratic elution. The content of the major acylated flavonol glycoside, kaempferol 3-0-[$6'-O-{p}-coumaroyl-{\beta}-_D-glucosyl(1{\rightarrow}2)-{\alpha}-_L-rhamnoside$] was about 8.0% and 0.55% for EtOAc fraction and MeOH extract, respectively.

• Journal of Forest and Environmental Science
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• v.23 no.1
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• pp.1-4
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• 2007

The bark of Juglans mandshurica Maxim. was collected, extracted with acetone-$H_2O$ (7:3, v/v), fractioned with n-hexane, $CH_2Cl_2$ and EtOAc, then each fraction was freeze-dried to give some powders. A portion of the EtOAc (28.4 g) fraction was chromatographed on a Sephadex LH-20 column eluting with a series of MeOH-$H_2O$ and EtOH-hexane mixture. Four gallotannins, gallic acid (1), ellagic acid (2), 1,2,4,6-tetra-O-galloyl-${\beta}$-D-glucose (3) and 1,2,3,4,6-penta-O-galloyl-${\beta}$-D-glucose (4), have been isolated from the EtOAc fraction Their structures were elucidated on the basis of chemical evidence and spectrometric analysis such as NMR and MS. The antioxidant activities on each fraction and the isolated gallotannins were evaluated by DPPH radical scavenging test.