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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Chemical Society
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Journal DOI :
Korean Chemical Society
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Volume & Issues
Volume 23, Issue 6 - Dec 1979
Volume 23, Issue 5 - Oct 1979
Volume 23, Issue 4 - Aug 1979
Volume 23, Issue 3 - Jun 1979
Volume 23, Issue 2 - Apr 1979
Volume 23, Issue 1 - Feb 1979
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Calculation of the Dipole Moments for Tetrahedral and Square Planar
Type Complexes [M(Ⅱ) = Ni(Ⅱ), Co(Ⅱ), Cu(Ⅱ) or Zn(Ⅱ)]
Ahn Sangwoon ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 1~6
The dipole moments for square planar and tetrahedral
type complexes are calculated, using the expansion method for spherical harmonics [M(II) = Co(II), Ni(II), Cu(II) or Zn(II)]. The calculated values of the dipole moments for these complexes are in the range of the experimental values. The possible structures for these complexes in benzene solution are discussed on the basis of the calculated dipole moments and the the magnetic properties.
Changes in Solution Properties of Poly(trans-5-methylproline) During Mutarotation
Han Man Jung ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 7~14
Changes in CD, ORD and uv-spectra during the mutarotation of poly(trans-5-methyl-L-proline) (PTMP) were studied. The forward mutarotion of PTMP occurred in strong organic acids and trifluoroethanol, while the reverse mutarotation was observed by dilution of the trifluoroethanol solution with excess aliphatic alcohols. The changes in CD, ORD and uv-spectra during the forward and reverse mutarotation proceeded paralell to those found for the mutarotation of polyproline. The chemical shift of the
proton was shifted downfield about 0.3 ppm during the forward mutarotation. The reduced viscosity for the forward mutarotation increased from 0.15 to 0.26 (dl/g) during 5 days. The equilibrium between form I and form II was estabilished in an appropriate solvent mixture. All changes in solution properties mentioned above are similar to those found for polypoline. These results support that the two forms of PTMP are the same conformations as polyproline form I and form II, i. e., a right-handed helix with all cis amide bonds and a lefthanded helix with all trans amide bonds.
Bonding and Antibonding Regions (I)
Kim Hojing ; Lee Duckhwan ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 15~19
The new concept of the Bonding and Antibonding Regions in the transition density space is developed from the Integral Hellmann-Feynman Theorem and the positive definiteness of the transition density. The unility of this concept is fully demonstrated for H2 system. It is expected that the nature of the electronic perturbation energy due to the change of nuclear configuration can be successfully understood by using this concept. Properties of the transition density is briefly discussed.
Bonding and Antibonding Regions (II). Origin of Barriers to Internal Rotation of
Kim Hojing ; Lee Duckhwan ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 20~29
The origin of barriers to internal rotation of hydrogen peroxide and ethane is investigated by using the concept of Bonding and Antibonding Regions. The strong bond formations between the axial and end atoms on the same side make the real charge densities in these molecules less dependent on conformations than those in the hypothetical molecules having no axial atoms. Thus, the existence of the axial atoms should induce the migration of the transition density from the Bonding region to the Antibonding region. Barrier to internal rotation can be understood in terms of this migration of the transition density to such an extent that the change in nuclear-nuclear repulsion energy becomes the dominating part of the total perturbation energy.
Studies on Biogenetic-type Synthesis of Natural Products (I). Synthesis and Reactions of Methyl 3-Hydroxymethylorsellinate
Lee, Eun ; Suh Junghun ; Hong, Won Pyo ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 30~36
Methyl 3-hydroxymethylorsellinate was synthesized from orcinol and various acetylation methods were studied. Two of three possible diacetates were prepared by short-interval acetylation procedure.
Kinetic Studies on the Reaction of Benzyl m-Nitrobenzenesulfonate with N,N-Dimethylanilines
Yoh Soo-Dong ; Lee Mu-Sang ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 37~41
The kinetics of the reaction of benzyl m-nitrobenzenesulfonate with m-and p-substituted N,N-dimethylanilines in acetone have been investigated by an electric conductivity method. The effects of substituents on the reactivity of N,N-dimethylaniline and the existence of linear free energy relationship were discussed. The rate constants k were in the range 2.55∼487
and increased with the electron donating ability of substituents. In the present reaction, the Hammett plot was correlated with
substituent constant, especially using the new
value of 0.35 in p-MeO and it's
value was found to be -1.37. r value for the reaction was very large than the value obtained in the reaction of benzyl bromide.
linear relationship was shown between rate constant and basicites except for p-MeO resulted from solvent effect. From the Bronsted plot, this reaction was suggested that the cleavage of the C
O bond in the
transition state proceed the bond formation.
Beckmann Rearrangement of Ring A Steroidal Oxime Using the Carbon tetrachloride-triphenylphosphine
Kim Jack C. ; Choi Soon-Kyu ; Park Won-Woo ; Lee Yong-Tae ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 42~45
The experimental procedures of Beckmann rearrangement mostly involve the use of vigorous conditions such as strongly acidic reagents (conc. HCl,
, etc.) or elevated temperatures, which frequently cause isomerization of ketooximes prior to rearrangement.We have effected the Beckmann rearrangement on
-cholestan-3-one oxime using the carbon tetrachloride-triphenylphosphine reagent under mild, neutral conditions to give 3-aza-A-homo-
-cholestan-4-one. This new, mild, facile and rapid general method of Beckmann rearrangement is presented, and compared with the classical (more conventional) Beckmann reagent of polyphosphoric acid.
The Efficient Synthesis of 6-O-(2-Acetamido-2-deoxy-
)-D-glucopyranosyl)-D-galactopyranose and Its Derivatives
Chung Bong Young ; Sim Young Key ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 46~51
Condensation of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-
-D-glucopyranosyl bromide (2) with 1,2;3,4-di-O-isopropylidene-
-D-galactopyranose (3) in the presence of silver triflate and syn-collidine gave 1,2;3,4-di-O-isopropylidene-6-O-(3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-
-D-galactopyranose (4) in
yield. Cleavage of phthalimido group and de-O-acetylation with hydrazine, acetylation, and hydrolysis of isopropylidene and O-acetyl groups furnished 6-O-(2-acetamido-2-deoxy-
-D-glucopyranosyl)-D-galactopyranose (1) with overall yield of
starting from 3. Some other derivatives of 1 which have free hydroxyl groups at the specific position have also been prepared from 4. These compounds could be used as precursors for further glycosidation reactions.
Effects of Metallaic Dialkyldithiophosphates on Lubricating Oil
Moon Tak Jin ; Kwon Oh Kwan ;
Journal of the Korean Chemical Society, volume 23, issue 1, 1979, Pages 52~58
Metallic dialkyldithiophosphates are widely used in lubricating oils as antioxidant and antiwear agents. Zinc DDTP are used most frequently in lubricating oil. Zinc, lead, tin and cobalt DDTP were prepared with primary and secondary alkyl groups. The effects of oxidation, thermal stability, metal corrosion and antiwear of each metallic DDTP prepared were studied. Based on the results, cobalt DDTP has a significant effect of antiwear on chrome alloy steel comparing with the other metallic DDTP. Also cobalt DDTP has a characteristic property of thermal sensitivity in its color, which was shown by the color change from brown to blue over a certain temperature. Another phenomenon obtained was that all metallic DDTP initiates the effect of antioxidation at the time of reaching to a certain effective acid concentration in lubricating oil.