• Title/Summary/Keyword: Tertiary Amide

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Studies of Tertiary Structures of Mastoparan B and Alanine Analogues by NMR Spectroscopy

  • Kyeunghee Yu;Kang, Shin-Won;Park, Nam-Gyu;Kim, Yangmee
    • Proceedings of the Korean Biophysical Society Conference
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    • 1999.06a
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    • pp.33-33
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    • 1999
  • Mastoparan B (MP-B), an antimicrobial cationic tetradecapeptide amide isolated from the venom of the hornet Vespa basalis, is an amphiphilic ${\alpha}$-helical peptide. In order to study the relationship between the structure and biological activity, we used the three analogues by replacing amino acids with alanine (4LysAla: 4MP-B, 12-LYsAla: 12MP-B, 9TrpAla: 9Mp-B).(omitted)

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Interface Characteristics of Ion Beam Mixed Cu/polyimide system

  • G.S.Chang;Jung, S.M.;Lee, Y.S.;Park, I.S.;Kang, H.J.;J.J.Woo;C.N.Whang
    • Journal of the Korean Vacuum Society
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    • v.4 no.S2
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    • pp.1-7
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    • 1995
  • Cu(400$\AA$)/Polyimide has been mixed with 80 keV Ar+ and N2+from 1.0X1015ions/$\textrm{cm}^2$ to 2.0X1016 ions/$\textrm{cm}^2$. The changes of chemical bond and internal properties of sample are investigated by X-ray photoelectron spectroscopy(XPS). The quantitative adhesion strength is measured by using scratch test. The optimized mixing condition is that Cu/PI is irradiated with 80 keV N2+ at a dose of 1.0X1015 ions/$\textrm{cm}^2$, because N2+ ions can product more pyridine-like moiety, amide group, and tertiary amine moiety which are known as adesion promoters than Ar+.

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Reaction of Representative Organic Compounds with Sodium Borohydride in the Presence of Aluminum Chloride (염화알루미늄 존재하에서의 수소화붕소나트륨과 대표적 유기화합물과의 반응)

  • Yoon Nung Min;Ho Jun Leeq;Jin Soon Chung
    • Journal of the Korean Chemical Society
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    • v.17 no.4
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    • pp.275-285
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    • 1973
  • The addition of one mole of aluminum chloride to three moles of sodium borohydride in tetrahydrofuran gives a turbid solution with enormously more powerful reducing properties than those of sodium borohydride itself. The reducing properties of this reagent were tested with 49 organic compounds which have representative functional groups. Alcohols liberated hydrogen immediately but showed no sign of hydrogenolysis of alkoxy group. Aldehydes and ketones were reduced rapidly within one hr. Acyl derivatives were reduced moderately, however, carboxylic acids were reduced much more slowly. Esters, lactones and epoxides were reduced readily than sodium borohydride or borane. Tertiary amide was reduced slowly, however, primary amide consumed one hydride for hydrogen evolution but reduction was sluggish. Aromatic nitrile was reduced much more readily than aliphatic nitrile. Nitro compounds were inert to this reagent but azo and azoxy groups were slowly attacked. Oxime was reduced slowly but isocyanate was only partially reduced. Disulfide and sulfoxide were attacked slowly but sulfide and sulfone were inert. Olefin was hydroborated rapidly.

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Reaction of Lithium n-Butylborohydride with Selected Organic Compounds Containing Representative Functional Groups

  • Chong-Suh Pyun;Jong-Chan Son;Nung-Min Yoon
    • Bulletin of the Korean Chemical Society
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    • v.4 no.1
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    • pp.3-9
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    • 1983
  • Lithium n-butylborohydride was prepared from borane-dimethylsulfide (BMS) and n-butyllithium, and the approximate rates and stoichiometrics of its reactions with selected organic compounds containing representative functional groups were studied in THF at room temperature. Phenol and benzenetiol liberated hydrogen quickly and quantitatively, and the reactions of primary alcohols, 2,6-di-ter-butylphenol and 1-hexanethiol liberated hydrogen quantitatively within 3 hrs, whereas the reactions of secondary and tertiary alcohols were very slow. Aldehydes and ketones were reduced rapidly and quantitatively to the corresponding alcohols. Cinnamaldehyde utilized 1 equiv. of hydride rapidly, suggesting the reduction to cinnamyl alcohol. Carboxylic acids evolved 1 equiv. of hydrogen rapidly and further reduction was not observed. Anhydrides utilized 2 equiv. of hydride rapidly but further hydride uptake was very slow, showing a half reduction. Acid chlorides were reduced to the alcohol stage very rapidly. All the esters examined were reduced to the corresponding alcohol rapidly. Lactones were also reduced rapidly. Expoxides took up 1 equiv. of hydride at a moderate rate to be reduced to the corresponding alcohols. Nitriles and primary amides were inert to this hydride system, whereas tertiary amide underwent slow reduction. Nitroethane and nitrobenzene were reduced slowly, however azobenzene and azoxybenzene were quite inert. Cyclohexanone oxime evolved 1 equiv. of hydrogen rapidly, but no further reduction was observed. Phenyl isocyanate and pyridine N-oxide were proceeded slowly, showing 1.74 and 1.53 hydride uptake, respectively in 24 hours. Diphenyl disulfide was reduced rapidly, whereas di-n-butyl disulfide, sulfone and sulfonic acids were inert or sluggish. n-Hexyl iodide and benzyl bromide reacted rapidly, but n-octyl bromide, n-octyl chloride, and benzyl chloride reacted very slowly.

Calculation of the Ideal Positions of Hydrogen Atoms in Compounds (화합물내에서의 수소원자의 이상적 위치계산)

  • Suh Il-Bwan;Kim Kyung-Han;Oh Mi-Ran;Park Koon Ha;Kim Moon-Jib
    • Korean Journal of Crystallography
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    • v.8 no.1
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    • pp.59-63
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    • 1997
  • A method for the calculation of the idealized hydrogen positions in the following seven different kinds of compounds has been shown: (1) tertiary C-H, (2) secondary C-H, (3) $CH_3$ group with tetrahedral angles, (4) aromatic C-H or amide N-H, (5) O-H group with X-O-H angle tetrahedral, (6) terminal $X=CH_2$ or $X=NH_2^+$ with the hydrogen atoms in a plane and (7) acetylenic C-H with X-C-H linear.

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Assignment of ¹H and $^{13}C$ Nuclear Magnetic Resonances of Ganglioside $G_{A1}$

  • 이경익;전길자;류경임;방은정;최병석;김양미
    • Bulletin of the Korean Chemical Society
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    • v.16 no.9
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    • pp.864-869
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    • 1995
  • Investigation of the structures of the gangliosides has proven to be very important in the understanding of their biological roles such as regulation of differentiation and growth of cells. We used nuclear magnetic resonance spectros-copy in order to investigate the structure of GA1. In order to do this, the assignment of spectra is a prerequisite. Since GA1 does not have polar sialic acid, the spectral overlap is severe. In order to solve this problem, we use 2D NMR spectroscopy and heteronuclear 1H/13C correlated spectroscopy in this study. Here, we report the complete assignment of the proton and the carbon spectra of the GA1 in DMSO-d6-D20 (98:2, v/v). These assignments will be useful for interpreting 1H and 13C NMR data from uncharacterized oligosaccharides and for determining the linkage position, the number of sugar rings, and the sequence of new ganglioside. Amide proton in ring Ⅲ shows many interring nOes and has intramolecular hydrogen bonding. This appears to be an important factor in tertiary folding of GA1. Based on this assignment, determination of three dimensional structure of GA1 will be carried out. Studies on the conformational properties of GA1 may lead to a better understanding of the molecular basis of its functions.

ENHANCED ADHESION STRENGTH OF Cu/polyimide AND Cu/Al/polyimide BY ION BEAM MIXING

  • Chang, G.S.;Kim, T.G.;Chae, K.H.;Whang, C.N.;Zatsepin, D.S.;Kurmaev, E.Z.;Choe, H.S.;Lee, Y.P.
    • Journal of the Korean Vacuum Society
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    • v.6 no.S1
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    • pp.122-126
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    • 1997
  • the Cu/polyimide system is known to be the best candidate for a multilevel interconnection system due to the low resistance of Cu and to the low dielectric constant of polyimide respectively. Ion beam mixing of Cu(40nm)/polyimide was carried out at room temperature with 80 keV Ar+ and N2+ form $1.5\times$1015 to 15$\times$1015 ions/cm2. The quantitative adhesion strength was measured by a standard scratch test. X-ray photoelectron spectroscopy and x-ray emission spectrocopy are employed to investigate the chemical bonds and the interlayer compound formation of the films Cu/Al/polyimide showed more adhesion strength than Cu/polyimide after ion beam mixing and N2+ ions are more effective in the adhesion enhancement than Ar+ with the same sample geometry. The XES results shows the formation of interlayer compound of CuAl2O4 which can reflect more adhesive Cu/Al/polyimide which has not been reported previously. The latter results is understood by the fact that N2+ ions produce more pyridinelike moiety, amide group and tertiary amine moiety whcih are known as adhesion promotors.

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Synthesis and Characterization of New Polyaza Macrocyclic Nickel(Ⅱ) and Copper(Ⅱ) Complexes Two Nitrile or Imidate Ester Pendant Arms: Metal-Mediated Hydrolysis and Alcoholysis of the Nitrile Groups

  • Kang, Shin-Geol;Song, Jeong-Hoon;Jeong, Jong-Hwa
    • Bulletin of the Korean Chemical Society
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    • v.23 no.6
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    • pp.824-829
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    • 2002
  • New di-N-cyanomethylated tetraaza macrocycle 2.13-bis(cyanomethyl)-5.16-dimethyl-2,6,13,17-tetraazatricyclo[$16.4.0.0^7.12$]docosane $(L^2)$ has been prepared by the reaction of 3, 14-dimethyl-2,6,13,17-tetraazatricyclo $(L^1)$ with bromoacetonitrile. The square-planar complexes $[ML^2](ClO_4)_2(M=Ni(II)$ or Cu(II) can be prepared by the reaction of $L^2$ with the corresponding metal ion in acetonitrile. The cyanomethyl groups of $[ML^2](ClO_4)_2readily$ react with water to $yield[ML^3](ClO_4)_2$ containing pendant amide groups. The trans-octahedral complexes $[ML^4](ClO_4)_2$, in which two imidate ester groups are coordinated to the metal ion, can be also prepared by the reaction of $[ML^2](ClO_4)_2with$ methanol under mild conditions. The hydrolysis and alcoholysis reactions of $[ML^2](ClO_4)_2are$ promoted by the central metal ion, in spite of the fact that the cyanomethyl group is not involved in intramolecular coordination. The reactions are also promoted by a base such as triethylamine but are retarded by an $acid(HClO_4).Interestingly$, the imidate ester groups of $[ML^4]^2$ are unusually resistant to hydrolysis even in 0.1 M $HCIO_4$ or 0.1 M NaOH aqueous solution. Crystal structure of $[NiL^4](ClO_4)_2shows$ that the Ni-N (pendant imidate ester group) bond is rlatively strong; the Ni-N bond distance is shorter then the Ni-N(tertiary) distance and is similar to the Ni-N (secondary) distance.