• Title/Summary/Keyword: Carbon 13 NMR

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NMR Spectroscopic Study of Quinolone Carboxylic Acid Derivatives

  • Dongsoo Koh;Lee, Inwon;Park, Jongmin;Lee, Hyeseung;Yoongho Lim
    • Journal of the Korean Magnetic Resonance Society
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    • v.3 no.1
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    • pp.52-59
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    • 1999
  • Authors synthesized common intermediates which are applicable for potential antibiotics. Their complete 13C and 1H NMR chemical shift data as well as carbon-and proton-fluorine coupling constants are reported. The knowledge of proton and carbon-fluorine coupling constants may help one assign the NMR data of the fluorinated quinolone derivatives. These results agree with the data published previously.

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The Structure of Ligand, N-benzylisonitrosoacetylacetone Imine (리간드 N-Benzylisonitrosoacetylacetone Imine의 구조)

  • Byung Kyo Lee;Dae Sub O;Heung Lark Lee
    • Journal of the Korean Chemical Society
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    • v.32 no.6
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    • pp.549-556
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    • 1988
  • In order to study the changes for the structure of N-benzylisonitrosoacetylacetone imine synthesized already in organic solution, nmr and carbon-13nmr DEPT spectra of the this reagent have been studied. Based on the present studies, it is suggested that this reagent is monoxime having syn- and anti-form isomers and has tautomers in solution respectively.

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Identification of the chromophoric structure in alkali model lignin by 13C-NMR (13C-NMR에 의(依)한 알카리 모델리그닌의 착색구조(着色構造)에 관(關)한 연구(硏究))

  • Yoon, Byung Ho
    • Journal of Korean Society of Forest Science
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    • v.43 no.1
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    • pp.14-19
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    • 1979
  • On treatment with sodium hydroxide at $165^{\circ}$ for 1.5~3hr followed by air oxidation. vanillyl alcohol afforded colored materials. $^{13}C$-NMR spectrum of the material did not show any absorptions assigned to the carbons of chromophoric structures, but gave the valuable information on the chemical structures of the condensation products. On the other hand, the colored material specifically labelled by $^{13}C$ at the benzylic position was prepared by alkali treatment of vanillyl alcohol-[carbinol-$^{13}C$] followed by air oxidation, and $^{13}C$-NMR spectra of the material exhibited absorptions at 101.7 and 104.6 ppm due to the carbons of a quinonemethide structure, indicating that the quinomethide unit would be one of the important types of chromophores in which benzylic carbon of vanillyl alcohol was included.

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Synthesis of Poly(styrene carbonate) and Preparation of Styrene Carbonate by Thermal Degradation (Poly(styrene carbonate)의 합성 및 열분해에 의한 styrene carbonate의 제조)

  • Lee, Yoon Bae;Shin, Eun Jung;Yoo, Jin Yi
    • Applied Chemistry for Engineering
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    • v.19 no.1
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    • pp.133-136
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    • 2008
  • In order to decrease carbon dioxide, one of the green house gas, poly(styrene carbonate) has been synthesized from carbon dioxide and styrene oxide with zinc glutarate as a catalyst. The polymer has been identified as an alternating copolymer by spectroscopic analysis, FT-IR, $^1H$-NMR, and $^{13}C$-NMR. The number average molecular weight ($M_n$) of the polymer is $5.0{\times}10^4g/mol$ and the glass transition temperature ($T_g$) is $88^{\circ}C$ and its melting point ($T_m$) is $240^{\circ}C$. The cyclic carbonate, styrene carbonate, has been obtained by thermal degradation of the polymer via the unzipping mechanism.

Isolation and Identification of Macamides from the Lipidic Extract of Maca [Lepidium meyenii] using Supercritical Carbon Dioxide (초임계 이산화탄소를 이용한 maca [Lepidium meyenii]의 지질 추출물로부터 macamides 분리 및 동정)

  • Lee, Seung-Ho;Kang, Jung-Il;Lee, Sang-Yun;Ha, Hyo-Cheol;Song, Young-Keun;Byun, Sang-Yo
    • KSBB Journal
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    • v.23 no.2
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    • pp.153-157
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    • 2008
  • Maca (Lepidium meyenii) has been used as a food and medicine in Peru for thousands of years. More recently a wide array of commercial maca products have gained popularity as dietary supplements with claims of anabolic and aphrodisiac effects. Even though the biologically active principles of maca are not fully known, the lipidic extract of maca tubers containing macamides showed promising physiological activities. In this study, the lipidic extract were collected from maca tubers by using supercritical carbon dioxide ($SCO_2$). Substance estimated as macamide in the extract was isolated and purified by preparative HPLC with recycling system. Two of the purified substance was identified as N-benzyl-5-oxo-6E,8E-octadecadienamide and N-benzylhexadecan amide by LC/MS, $^1H$-NMR and $^{13}C$-NMR analyses.

A Study on the Component Analysis of Sappan Wood Extracts (소목 추출물의 구조분석)

  • 이상락;김인회;남성우
    • Textile Coloration and Finishing
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    • v.14 no.4
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    • pp.229-239
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    • 2002
  • Colorants were extracted from the heartwood of sappan lin. with MeOH under reflux, and the concentrate or the powder of dye was prepared by low pressure concentration method using suitable organic solvent. Various components were isolated from sappan wood, and the chemical structure and mechanism of compound having the excellent antibacterial and deodorization properties were analyzed. The results obtained are as follows ; The seventeen components of sappan wood were seperated by HPLC chromatography, and the five components among them were existed more than 6% and the other components were existed lower than 0.6%. The resolving powers of the non-polar solvent and polar solvent systems were evaluated by their ability to resolve the samples. It showed that chloroform-methanol-water(800:150:10) system has the best resolving power. Although the seperation rate is very slow, polyamide C-100 column chromatography gives a clear seperation of sappan wood. On the basis of the spectrometric data such as IR, UV, $GC-Mass,\;^1H-NMR,\;^{13}C-NMR\;and\;^1H-^{ 13}C-NMR$, the chemical structure of compound haying the excellent antibacterial and deodorization properties was established as brazilin containing the functional groups such as two quaternary carbon, one benzyl carbon, methylene contiguous to oxygen and methylene caused by oxygen atom.

Intramolecualr cyclization of a dipyrromethane by an electrophilic aromatic substitution reaction producing a new chiral compound

  • Kim, Seung Hyun;Kim, Sung Kuk
    • Journal of the Korean Magnetic Resonance Society
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    • v.22 no.4
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    • pp.115-118
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    • 2018
  • Dipyrromethane 2 functionalized with 3-chloropropyl group on the meso carbon undergoes an unusual intramolecular electrophilic aromatic substitution reaction in the presence of $NaN_3$ instead of a simple nucleophilic substitution reaction. As a result, a new chiral dipyrromethane 1 was synthesized. In this reaction, the ${\beta}$-carbon of the pyrrole ring functions as a nucleophile while the carbon next to the chlorine atom acts as an electrophile. Interestingly, this reaction progresses even in the absence of an acid catalyst. Compound 1 was fully characterized by $^1H-^1H$ and $^1H-^{13}C$ COSY NMR spectroscopic analyses and the high resolution EI mass spectrometry.

Assignment of the Carbonyl Carbon Resonances in Anti-Dansyl Antibodies (항 단실 항체의 카르보닐탄소 유래 시그날의 귀속)

  • ;;Koichi Kato;Yoji Arata
    • YAKHAK HOEJI
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    • v.39 no.5
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    • pp.516-520
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    • 1995
  • The anti-dansyl antibodies were specifically labeled with stable isotope by growing hybridoma cells in serum-free medium. Assignments of the observed carbonyl carbon resonances have been determined by using $^{13}C-{15}N$ double labeling method in order to assign the Leu resonances. However, when the identical dipeptide appears more than twice in the polypeptide sequences, we applied the proteolytic fragments in the fragment-specific method. Carboxypep-tidase B-treated antibody has also been used to assign the Lys-447 in C terminal amino acid. These unambiguously assigned carbonyl carbon resonances in antibodies are thought to be useful in elucidating not only the structure of antibodies but also the structure-function relationship in the antibody by $^{13}C$ neuclear magnetic resonance spectroscopy.

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Carbon-13 CP MAS NMR Study on Structures of Octadecyl Chains Influenced by Co-Presence of 3-Aminopropyl Chains on SBA-15

  • Han, Oc-Hee;Bae, Yoon-Kyung;Jeong, Soon-Yong
    • Bulletin of the Korean Chemical Society
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    • v.29 no.2
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    • pp.405-407
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    • 2008
  • Functionalized SAB-15 samples by octadecyltrimethoxysilane (OTC) were studied by 13C magic angle spinning (MAS) cross polarization (CP) nuclear magnetic resonance (NMR) spectroscopy. In the SBA-15 sample fully functionalized by 3-aminopropyltrimethoxysilane (APS) and OTC in 1:1 molar ratio, octadecyl chains were observed to have, on average, more trans conformation than those in the SBA-15 samples fully modified by OTC only. Our results confirm that long chain molecules tend to organize themselves better in the co-presence of short chain molecules on the surface of mesoporous materials by packing of the different length chains in an interdigitized fashion even when the short chains are long enough to have three carbons and a functional group at the ends. In addition, our results indicate that solid-state 13C CP MAS NMR spectroscopy is a simple and non-destructive method to probe the molecular structures of the domains composed of long alkyl chains.

Paratope Mapping of Anti-Ex-A IgG as Studied by NMR (NMR에 의한 anti-Ex-A IgG의 항원결합부위 해석)

  • Kim, Ha-Hyeong;Lee, Gwang-Pyo
    • YAKHAK HOEJI
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    • v.40 no.4
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    • pp.422-427
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    • 1996
  • The anti-Ex-A IgG was specifically labeled with stable isotopes, DL-His-2,4-$d_2$, L-Phe-$d_5$, L-Trp-$d_5$, L-Tyr-2,6-$d_2$ and L-[1-$^{13}C$]Trp, by growing hybridoma cell in serum-free medium. By use of NMR spectroscopy with selectively labeled Fab fragment, we applied a paratope mapping on antigen-antibody complex. Assignments of the observed carbonyl carbon resonances have been determined by using $^{13}C$-$^{15}N$ double labeling method in order to assign the Trp resonances. Photo CIDNP was also applied to investigate the antigen-binding site(s) on the surface residues of antibody. We found that Trp 36, which is located at the $V_H$ domain, is an important residue to bind to Ex-A, however, two Tyr on the surface of anti-Ex-A IgG plays no crucial role to bind to antigen. On the basis of these results, we demonstrate that stable isotope-aided NMR strategy can be extended to molecular structural analyses of the complex of an Fab fragment and a protein antigen.

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