• Title/Summary/Keyword: $^{11}B$ NMR

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Conformations of Tetrahomodioxa-p0phenylcalix[4]arene Alkyl Ethers

  • No, Kwang-Hyun;Park, Young-Ja
    • Bulletin of the Korean Chemical Society
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    • v.23 no.11
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    • pp.1629-1634
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    • 2002
  • Reaction of tetrahomodioxa p-phenylcalix[4]arene with alkyl halide and NaH in DMF leads to the title tetra-alkylated derivatives, 7,13,21,27-tetra-phenyl-29,30,31,32-tetraalkyloxy-2,3,16,17-tetrahomo-3,17-dioxacalix [4]arenes, their preferred conformations were determined by NMR spectra as C-1,2-alternate. The molecular structure of allyl derivative has been solved by X-ray diffraction methods. The molecules have a conformation with pseudo center of symmetry. The benzene ring A is up, ring C is down, B and D rings are flat with respect to the plane of the macrocyclic ring.

Some Pyridyl- and Thiophenyl-Substituted 1,2,4-Triazolo[3,4-b]1,3,4-thiadiazole Derivatives as Potent Antibacterial

  • Maqsood, Muhammad Rizwan;Hanif, Muhammad;Rafiq, Muhammad;Saleem, Muhammad;Zaib, Sumera;Khan, Aftab Ahmed;Iqbal, Mazhar;Iqbal, Jamshed;Rama, Nasim Hasan;Seo, Sung-Yum;Lee, Ki-Hwan
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.4180-4184
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    • 2012
  • The target compounds 6-11a-e were synthesized by condensing 4-amino-5-aryl-3H-1,2,4-triazole-3-thiones 5a-f with various aromatic carboxylic acids in the presence of phosphorous oxychloride. The structures of newly synthesized compounds were characterized by IR, $^1H$ NMR, $^{13}C$ NMR, elemental analysis and mass spectrometric studies. All the synthesized compounds were screened for their antibacterial activity. Almost all the tested compounds were potent against four different strains of bacteria when compared with that of reference drug ciprofloxacin. Compounds 6c, 6e, 8d, 9b, 9e, 11a and 11b showed nearly equal or lower MIC values than standard drug, against all four tested bacterial strains but rest of the compounds showed excellent antibacterial activities.

Isolation and Characterization of Cathepsin B inhilbitor Produced by Streptomyces luteogriseus KT-10 (Streptomyces luteogriseus KT-10 이 생산하는 Cathepsin B 저해물질의 분리 및 특성)

  • 한길환;김상달
    • Microbiology and Biotechnology Letters
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    • v.29 no.2
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    • pp.84-89
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    • 2001
  • Isolation and Characterization of Cathepsin B inhibitor Produced by Streptomyces luteogriseus KT-IO. Han, Kil~Hwan and Sang~Dal Kim*. Department of Applied Microbiology, Yeungnam Universit}/t Kyongsan 712749, Korea - The cathepsin B inhibitor produced by Streptomyces luteogriseus KT-IO was very stable in heat, acidic and alkaline conditions. The cathepsin B inhibitor was isolated from the extracted fraction of culture broth with butanol, methanol and chloroform subsequently, the inhibitor was purified with following several column chromatography sLlch as DEAE-Sephadex A-25, Sephadex G-15, silica gel 60, Sephadex LH-20, and preparative HPLC. The cathepsin B inhibitor showed positively to detective reaction of ninhydrine, 5% H2S04, iodine, but negatively to the reaction of Ehrlich's reagent, DNS, aniline. The molecular formular of cathepsin B inhibitor was elucidated by JR, lH and 13C-NMR, FAB mass and elemental analyzer. Consequently, it was identified as C4HlI04N6. The cathepsin B inhibitor had the mode of competitive inhibition with the reaction of cathepsin B.

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Identification of the Polyacetylenes extracted from Acanthopanax Senticosus by Petroleum Ether (가시오가피(Acanthopanax senticosus)의 석유에테르 추출물 중 polyacetylene계 물질의 동정)

  • Yang, Hyo-Jin;Kim, Eun-Mi;Chang, Kyu-Seob
    • Korean Journal of Agricultural Science
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    • v.35 no.1
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    • pp.11-17
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    • 2008
  • This study was conducted to isolate polyacetylenes from the Acanthopanax senticosus and to identify the chemical structure of the polyacetylenes by UV, IR, $^1H$-NMR and $^{13}C$-NMR. One of the liposoluble materials was extracted with petroleum ether. Polyacetylene compounds were collected through solvent fractionation at silica gel column chromatograph. The HPLC was used for the semi-preparative separation IR spectra of fraction 5 showed triple bonds at $2256cm^{-1}$ and double bond at $1654cm^{-1}$, respectively, $^1H$-NMR spectra of Fraction 5 showed the double bond at 5.35-5.48 ppm. Triple bond at 64.0. 71.2, 74.2, 80.2 ppm and double bond at 121.89, 133.0 ppm were observed in the $^{13}C$-NMR spectra.

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Complete $^1H$-NMR and $^{13}C$-NMR spectral analysis of the pairs of 20(S) and 20(R) ginsenosides

  • Yang, Heejung;Kim, Jeom Yong;Kim, Sun Ok;Yoo, Young Hyo;Sung, Sang Hyun
    • 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).

Structure of SrO-B2O3-Al2O3 and SrO-B2O3-SiO2 glasses Using 11B Nuclear Magnetic Resonance (11B NMR 방법에 의한 SrO-B2O3-Al2O3와 SrO-B2O3-SiO2 유리들의 구조에 관한 연구)

  • Moon, Seong-Jun
    • Journal of Korean Ophthalmic Optics Society
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    • v.7 no.2
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    • pp.19-25
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    • 2002
  • Ternary $xSrO-yB_2O_3-0.1Al_2O_3$ and $xSrO-yB_2O_3-0.1SiO_2$ glasses were prepared as a function of R(${\equiv}x/y$). The fraction of four-coordinated brans ($N_4$), symmetric three-coordinated barons ($N_{3S}$), and asymmetric three-coordinated barons ($N_{3A}$) were determined quantitatively to study the structures of these glasses by $^{11}B$ NMR. The values of $Q_{cc}$ and ${\eta}$ for $BO_3$ unit in the glasses were 2.74MHz and 0.22, those for $BO_3{^-}$ unit were 2.54MHz and 0.55, and those for $BO_4$ unit 0.60~0.75MHz and 0.00, respectively. The structure of SrBAl glass at $R_{1st}$ consisted of tetraborate ($[B_8O_{13}]^{-2}$) units and 1st-modified diborate ($[B_2Al_2O_7]^{-2}$) units, and those for the glass at $R_{max}$consisted of diborate ($[B_4O_7]^{-2}$) units, metaborate ($[BO_2^{-1}]$), 1st-modified diborate units, and 2nd-modified diborate ($[B_2Al_2O_8]^{-4}$) units. Due to the oxygens introduced from the strontium oxide. $AlO_4$ units were preferably formed rather than $BO_4$ units. And, the structure of SrBSi glasses in the region $R{\leq}0.5$ could be viewed as binary $SrO-B_2O_3$ glasses structure diluted by silicate oxide: therefore, the Si atoms of the glasses did not contributed to the change the configuration around the boron atoms. The silicate oxide was formed the $SiO_4{^-}$ units rather than the $BO_3{^-}$ units by the oxygens introduced from the storntium oxide in the region of $R{\geq}R_{max}$, and structure of those glass at $R_{max}$ consisted of diborate units, metaborate units loose $BO_4([BO_2]^{-1})$, and $SiO_4{^-}([SiO_{2.5}]^{-1})$ units.

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Structure elucidation of a newly isolated saponin from Clerodendrum serratum (L) Moon

  • Bhujbal, Santosh S.;K.Nanda, Rabindra;S.Deoda, Ramesh;Kumar, Dinesh;Kewatkar, Shailesh M.;S.More, Laxmikant;J.Patil, Manohar
    • Advances in Traditional Medicine
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    • v.10 no.4
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    • pp.319-321
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    • 2010
  • Plant saponins are widely distributed amongst plants and have a wide range of biological properties. Icosahydropicenic acid, $C_{51}H_{80}O_{19}$ ((4S,6bS)-8a-((4,5-dihydroxy-6-methyl-3-((3R)-3,4,5-trihydroxy-6-methyl-tetrahydro-2H-pyran-2-yloxy)-tetrahydro-2H-pyran-2-yloxy)carbonyl)-2-hydroxy-4, 6a, 6b, 11, 14b-pentamethyl-11-(2-methylprop-1-enyl)-3-(3,4,5-trihydroxy-6-(hydroxymethyl) - tetrahydro-2Hpyran-2-yloxy)-1, 2, 3, 4, 4a, 5, 6, 6a, 6b, 7, 8, 8a, 9, 10, 11, 12, 12a, 14, 14a, 14b-icosahydropicene-4-carboxylic acid), a new saponin was first time isolated from the roots of Clerodendrum Serratum (L) Moon (Verbenaceae). The structure elucidation of the compound was carried out by $^1H$ NMR and DART-MS studies.

Solid state MAS NMR Investigation on the Local Structures of xV2O5-B2O3-yNa2O Glasses

  • Kim, Sun-Ha;Han, Oc-Hee;Kang, Jae-Pil;Song, Seung-Ki
    • Bulletin of the Korean Chemical Society
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    • v.30 no.3
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    • pp.608-612
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    • 2009
  • The local structures of the boron and vanadium sites in the ternary glass $xV_2O_5-B_2O_3-yNa_2O$ were studied by $^{11}B\;and\;^{51}V$ magic angle spinning (MAS) nuclear magnetic resonance (NMR). With increasing x, the mole ratios of the $BO_3\;and\;BO_4$ structures were enhanced, as were the quadrupole asymmetry parameters for the $BO_3$ structures, while the quadrupole coupling constants for the sites were reduced. However, the opposite trends were observed with increasing y, implying that $V_2O_5$ and $Na_2O$ play opposite roles. The $VO_4,\;VO_5\;and\;VO_6$ structures with all oxygens bonded to the vanadium neighbors were identified. Vanadiums bonded to the greater number of oxygens were more populated at higher contents of $Na_2O\;and\;V_2O_5$. In addition, the $VO_4$ structures with at least one oxygen bonded to boron instead of vanadium were detected at low $Na_2O$ contents. The electron densities of various vanadium oxide structures were affected by the weight densities and vanadium ion densities. The $VO_4$ structures were more likely to be vanadium oxide structures right next to $V4^{+}$ ions.

Synthesis and Study of Antibacterial and Antifungal Activities of Novel 2-[[(Benzoxazole/benzimidazole-2-yl)sulfanyl]acetylamino]thiazoles

  • Kaplancikli, Zafer-Asim;Gulhan, Turan-Zitouni;Revial, Gilbert;Guven, Kiymet
    • Archives of Pharmacal Research
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    • v.27 no.11
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    • pp.1081-1085
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    • 2004
  • Several 2-[[(benzoxazole/benzimidazole-2-yl)sulfanyl]acetylamino]thiazoles derivatives were synthesized by reacting 4-substituted-2-(chloroacetylamino)thiazoles with benzoxazole/benzimidazole-2-thioles in acetone and in the presence of $K_2CO_3$. The chemical structures of the compounds were elucidated by IR, $^1H-NMR$, and $FAB^{+}-MS$ spectral data. Their antimicrobial activities against Micrococcus luteus (NRLL B-4375), Bacillus cereus (NRRL B-3711), Proteus vulgaris (NRRL B-123), Salmonella typhimurium (NRRL B-4420), Staphylococcus aureus (NRRL B-767), Escherichia coli (NRRL B-3704), Candida albicans and Candida globrata (isolates obtained from Osmangazi Uni. Fac.of Medicine) were investigated and in this investigation, a significant level of activity was illustrated.

Structure of Three New Terpenoids, Spiciformisins a and b, and Monocyclosqualene, Isolated from the Herbs of Ligularia fischeri var. spiciformis and Cytotoxicity

  • Lee, Kyung-Tae;Koo, Sung-Ja;Jung, Seung-Hee;Choi, Jong-Won;Jung, Hyun-Ju;Park, Hee-Juhn
    • Archives of Pharmacal Research
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    • v.25 no.6
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    • pp.820-823
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    • 2002
  • The diethylet er fraction from the leaves extract of Ligularia fischeri var. spiciformis (Compositae) was subjected to silica gel column chromatography and yielded three new terpenoids named spiciformisin a (1), spiciformisin b (3), and monocyclosqualene (2). Acyclic diterpenes, spiciformisin a and -b, were established as 3,7,11,15-tetramethyl-1,3(20)-hexadecadiene and 3,7,11,15-tetramethyl-1,3,6,10,14-hexadecapentaene (IUPAC), respectively. A monocyclic triterpene, monocyclosqualene, were determined as [3,8,12,16,16-pentamethyl-(3,7,11,15-hexadecatetraenyl)]-3,3,5-trimethyl-1-cyclohexene. The structures were determined on the basis of NMR and MS analysis. Spiciformicin b showed potent cytotoxicity ($IC_{50},{\;}<9.7{;\}{\mu\textrm{g}}/ml$ against HL-60) in contrast to no cytotoxicity ($IC_{50},{\;}>200{\;}}{\mu\textrm{g}}/ml against HL-60 cells) of spiciformicin a with a cis-conjugated dienyl diexomethylene.