• Title/Summary/Keyword: Double bond

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Effects of Molecular Attraction and Orientations in the Vibration-Vibration Energy Exchange

  • Ree, Jong-Baik;Chung, Keun-Ho
    • Bulletin of the Korean Chemical Society
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    • v.7 no.2
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    • pp.124-129
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    • 1986
  • The effects of molecular attraction and orientations for the energy mismatch variance, vibrational energy level and double-quantum transition, in the vibration-vibration energy exchange, have been considered. The contribution of molecular attraction increases the exchange rate of the purely repulsive interaction, in general, significantly, but which becomes smaller as the temperature is increased. As the energy mismatch is increased, its contribution is also increased, but which is small. However, its contribution for the double-quantum transition is very paramount. At each orientation, the exchange rate constants have been calculated and compared with the results for rotational average, and it is found that the exchange rate is a strong function of the orientation angles of colliding molecules. We have also discussed about the system having the strong interaction such as the hydrogen bond, and it is found that for this system the preferred orientation should be considered in order to calculate the exchange rates.

Theoretical Studies on the Photochemical Reaction of Psoralen. Photocycloaddition of Angelicin with Thymine

  • Ja Hong Kim;Sung Ho Sohn;Gae Soo Lee;Kee Soo Yang;Sung Wan Hong
    • Bulletin of the Korean Chemical Society
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    • v.14 no.4
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    • pp.487-490
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    • 1993
  • A semiempirical methods (PM3-CI-UHF. etc.) for the evaluation of ground and excited state electronic structures of psoralens are applied to angelicin with thymine. The photocycloaddition reaction of angelicin with thymine were deduced to be formed by their preferable HSOMO-LUMO interactions. The photoadduct was inferred to be a C$_{4-}$cycloaddition product with the stereochemistry of cis-anti formed through [2+2] addition reaction between, the 3,4 double bonds of angelicin and the 5,6-double bond of thymine.

Regioselective Benzylic Thioether Formation from Polybydroxy Stilbene

  • Koh, Dongsoo;Park, Jongmin;Lim, Yoongho
    • Journal of Applied Biological Chemistry
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    • v.44 no.1
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    • pp.20-22
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    • 2001
  • We have attempted to synthesize polyhydroxy stilbene compounds through the benzyl thioether moiety. During synthesis, we unexpectedly observed that demethylation of the compound under $AlCl_3$ in ethanethiol resulted in a regioselective addition of thiol to the double bond as well as complete demethylation. We report on the regioselective short synthesis for general structure and its structural identification.

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Halogenation of Cannabinoids (Cannabinoid의 할로겐화)

  • Baek Seung-Hwa;Park No-Yeun
    • Journal of the Korean Chemical Society
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    • v.35 no.1
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    • pp.59-63
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    • 1991
  • Several types of cannabinoids have been halogenated in the aromatic ring in good yields with metal halide in the presence of 18-crown-6 on oxidation with m-chloroperbenzoic acid. This reagent system effects the regiospecific halogenation of activated aromatic ring over olefinic double bond.

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Concomitant Addition and Acetalization of α,β-Unsaturated Aldehydes with Diols

  • Jeon, Kyu-Ok;Yu, Ji-Sook;Lee, Chang-Kiu
    • Bulletin of the Korean Chemical Society
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    • v.25 no.11
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    • pp.1653-1656
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    • 2004
  • ${\alpha},{\beta}$-Unsaturated aldehydes such as acrolein and crotonaldehyde were reacted with diols in the presence of conc. sulfuric acid to give products of which concomitant addition to C-C double bond and acetalization took place. Boron trifluoride etherate and titanium tetrachloride gave only acetalization products.

Halogenation of Resorcinol Derivatives

  • Baek Seung-Hwa
    • Bulletin of the Korean Chemical Society
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    • v.9 no.1
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    • pp.13-15
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    • 1988
  • Several types of resocinols have been monobrominated in the ring in good yields with sodium bromide in the presence of 18-crown-6 on oxidation with m-chloroperbenzoic acid. Monoiodination takes place with 2'-(1-methylcyclohexen-3-yl)-5-(1,1-dimethylheptyl )-resocinol when sodium iodide is employed. This new reagent system, MX/18-crown-6/m-CPBA (M =$K^+, Na^+, X = Br^-, I^-X$ ), effects the regiospecific halogenation of activated aromatic ring over olefinic double bond.

Chemical Reactions in Solid State Complexes of 1,2-Polybutadiene and Palladium Chloride : High Temperature Infrared Study

  • Lee, Joon Y.;Laurence A. Belfiore
    • Bulletin of the Korean Chemical Society
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    • v.17 no.9
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    • pp.826-830
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    • 1996
  • Fourier transform infrared (FTIR) temperature studies were performed to examine the microstructural changes that occur in annealing process of the thin films of 1,2-polybutadiene (1,2-PBu)/palladium chloride (PdCl2) complex. The disappearance of the infrared absorption intensities at 1640, 1418, 994 and 910 cm-1 signifies the consumption of 1,2-vinyl groups of 1,2-PBu. The progressive loss of unsaturation and production of methyl groups as a function of temperature were identified by the enhanced infrared absorption intensities at 1447 and 1375 cm-1. The loss of pendent carbon-carbon double bond is considered to involve both palladium-catalyzed addition reaction and thermally induced cyclization.

Resolution of the Triacylglycerols Containing Conjugate Trienoic Acids into Their Molecular Species by HPLC in the Reversed-phase and Silver Ion Mode (Reversed-phase 및 $Ag^{+}$-HPLC에 의한 Conjugate Trienoic Acid 함유(含有) Triacylglycerol 분자종(分子種)의 상호분리(相互分離))

  • Kim, Seong-Jin;Woo, Hyo-Kyeng;Joh, Yong-Goe
    • Journal of the Korean Applied Science and Technology
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    • v.18 no.3
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    • pp.197-213
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    • 2001
  • Conjugate trienoic acids (CTA) occurred in triacylglycerols (TGs) of the seed oils of Trichosanthes kirilowii, Momordica charantia and Aleurites fordii, and they were easily converted to their methyl esters in a mixture of sodium methoxide-methanol without any structural destruction. The main fatty acids in triacylglycerol (TG) fraction of the seed oils of Trichosanthes kirilowii are $C_{18:2{\omega}6}$ (32.2 mol %), $C_{18:3{\;}9c.11t,13c}$ (38.0 mol %) and $C_{18:1{\omega}9}$ (11.8 mol %), followed with $C_{16:0}$ (4.8 mol %) and $C_{18:0}$ (3.1 mol %). The TG fraction was resolved into 20 TG molecular species according to the partition number (PN) by reversed-phase (RP)-HPLC. The main TG species were $DT_{c2}$, $MDT_{c}$ and $D_{2}T_{c}$, of which amounts reached 63 mol % of total TG molecular species. The TG sample was fractionated into 11 fractions according to the number of double bond in the molecule by $Ag^{+}-HPLC$ and the species of $DT_{c2}$, $MDT_{c}$ and $D_{2}T_{c}$ were also eluted as main components. The TG species containing CTA showed unusual behaviours in the order of elution by HPLC ; first, TG moleular species of $DT_{c2}$ (D; dienoic acid, $T_{c}$; punicic acid, $T_{ci}$; ${\alpha}-eleostearic$ acid, M ; monoenoic acid, $S_{t}$; stearic acid) was eluted earlier than $Mt_{c2}$, although they have the same PN number of 40, and, secondly, the species of $DT_{ci2}$ with eight double bonds was eluted earlier than that of $D_2T_{ci}$ with seven double bonds. Intact TG of the seed oils of Momordica charantia contained mainly fatty acids such as $C_{18:3{\omega}9c,11t,13t}$ (57.7 mol %), $C_{18:1{\omega}9}$ (17.4 mol %), $C_{18:0}$ (12.3 mol %) and $C_{18:2{\omega}6}$ (10.6 mol %), and was classified into 13 fractions by RP-HPLC. The main TG species were as follows ; $MT_{ci2}$ [$(C_{18:1{\omega}9})(C_{18:3\;9c,11t,13t})_{2}$, 39.1 mol %] and $S_{t}T_{ci2}$ [$(C_{18:0})(C_{18:3\;9c,11t,13t})_2$, 33.9 mol %] comprising about 73 mol % of total TG species, accompanied by $DT_{ci2}$ [$(C_{18:2{\omega}6})(C_{18:3\;9c,11t,13t})_{2}$, 7.3 mol %], $D_{2}T_{ci}$ [$ (C_{18:2{\omega}6})_{2}(C_{18:3\;9c,11t,13t})$, 3.6 mol %] and $MDT_{ci}$ [$(C_{18:1{\omega}9})(C_{18:2{\omega}6})(C_{18:3\;9c,11t,13t})$, 3.5 mol %]. Simple TG species of $T_{ci3}$ [$(C_{18:3\;9c,11t,13t})_3]$ was present in a small amount of 1.4 mol %, but other simple TG species were not detected. The TG was also resolved into 11 fractions according to the number of double bond by $Ag^{+}-HPLC$, and the species were mainly occupied by $MT_{ci2}$ [$(C_{18:1{\omega}9})(C_{18:3\;9c,11t,13t})_{2}$, 39.4 mol %] and $S_tT-{ci2}$ [$(C_{18:0})(C_{18:3\;9c,11t,13t})_{2}$, 35.4 mol %] $DT_{ci2}$ species with eight double bonds was also developed faster than $D_2T_{ci}$ one with seven double bonds as indicated in the analysis of TG of the seed oils of T. kirilowii, and $MT_{ci2}$ species with cis, trans, trans-configurated double bond was eluted earlier than $MT_{c2}$ species with cis, trans, cis-configurated double bond. The main components of fatty acid in total TG fraction isolated from the seed oils of of Aleurites fordii were in the following order ; $C_{18:3\;9c,11t,13t}$ (81.2 mol %)> $C_{18:2{\omega}6}$ (8.5 mol %)> $C_{18:1{\omega}9}$ (5.4 mol %)$. With resolution of the TG by RP-HPLC, eight fractions such as $T_{ci3}$, $Dt_{ci2}$, $D_{2}T_{ci}$, $MT_{ci2}$, $PT_{ci2}$ (P; palmitic acid), $PMT_{ci}$, $PDT_{ci}$ and $S_{t}T_{ci2}$ ($S_{t}$; stearic acid) were isolated, respectively. TG species of $T_{ci3}$ [$(C_{18:3\;9c,11t,13t})_{3}$, 54.2 mol %], $DT_{ci2}$ [$(C_{18:2{\omega}6})(C_{18:3\;9c,11t,13t})_{2}$, 15.0 mol %] and $MT_{ci2}$ [$(C_{18:1{\omega}9})(C_{18:3 9c,11t,13t})_{2}$, 14.8 mol %] were present as main species.