JSCS - Vol 65, No 7

JSCS Vol 65, No. 7

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Impresum (39 KB - pdf file); Content of Vol 65, No. 7 (75 KB - WinZip file); Instruction for authors (37 KB - pdf file); Editor´s Note (16 KB - WinZip file)

J.Serb.Chem.Soc. 65(7)457-472(2000)
UDC 535.243.1/.3:167.7
JSCS-2765
Review paper

REVIEW
Analytical application of derivative spectrophotometry

GORDANA V. POPOVIC, LIDIJA B. PFENDT* and VIOLETA M. STEFANOVIC*

Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, P.O.Box 146, YU-11000 Belgrade and
*Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 158, YU-11000 Belgrade, Yugoslavia

(Received 26 October 1999)
1. Introduction
2. Basic characteristics of derivative spectrophotometry
2.1. Increase of spectra resolution
2.2. Elimination of the influence of baseline shift and matrix interferences
2.3. Enhancement of the detectability of minor spectral features
2.4. Precise determination of the positions of absorption maxima
2.5. Signal-to-noise ratio (SNR)
2.6. Quantitative analysis
3. Analytical applications
3.1. Inorganic analysis
3.2. Organic and pharmaceutical analysis
3.3. Analysis of food and water
3.4. Application of derivative spectrophotometry for the determination of equilibrium constants
Keywords: theoretical aspect of derivative spectrophotometry, analytical application of derivative spectrophotometry, inorganic analysis, organic analysis, pharmaceutical ana-lysis, derivative spectrophotometry in chemical equilibria.

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J.Serb.Chem.Soc. 65(7)473-479(2000)
UDC 547.924:611.018.5:543.9
JSCS-2766
Original scientific paper

Determination of cholesterol in human serum by an enzymatic method with the application of DAOS reagent

MILENA JELIKIC-STANKOV, DEJAN STANKOV and SNEZANA PAUNOVIC*

Faculty of Pharmacy, Department of Analytical Chemistry, University of Belgrade, P.O.Box 146, YU-11224 Belgrade,
*Hospital "Dr. Dragisa Misovic", Biochemical Department, University of Belgrade, YU-11000 Belgrade, Yugoslavia

(Received 5 August 1999, revised 27 December 1999)
A sensitive and specific enzymatic method has been developed for the determination of the total and free cholesterol in human serum based on the application of the newly-synthesized N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethoxyaniline, (DAOS) Trinder's reagent. Using the proposed method, cholesterol could be determined in the concentration range of 0-15 mmol/L with a relative standard deviation of up to 1.1%. In order to find the optimal experimental conditions for the application of the DAOS reagent, the influence of its concentration on the linearity of the method, the influence of pH, as well as the influence of the activities of cholesterolesterase and cholesteroloxidase were examined. The obtained results of the determination of the total and free cholesterol were compared to the results obtained by the application of the most frequently employed enzymatic method in clinical practice, based on phenol as a reagent. The sensitivity of the method was 0.070 A/mmol/L, the limit of detection DL=0.03 mmol/L and the limit of quantification QL=0.09 mmol/L of cholesterol.
Keywords: cholesterol, enzymatic determination, N-ethyl-N-(2-hydroxy-3-sulfoppropyl)-3,5-dimethoxyaniline (DAOS) - modified Trinder's reagent.

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J.Serb.Chem.Soc. 65(7)481-490(2000)
UDC 547.826/827:547.556.5/547.631.2/
JSCS-2767
Original scientific paper

The kinetics of the reaction of 6-substituted nicotinic acids and some p-substituted benzoic acids with diazodiphenylmethane in various alcohols

SASA Z. DRMANIC, BRATISLAV Z. JOVANOVIC and MILICA M. MISIC-VUKOVIC

Departmant of Organic Chemistry, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 494, YU-11001 Belgrade, Yugoslavia

(Received 15 September 1999, revised 22 March 2000)
Rate constants have been determined for the reactions of diazodiphenylmethane with a number of 6-substituted nicotinic acids and p-substituted benzoic acids in twelve alcohols. A comparative study was used to evaluate and compare the Hammett r values and solvent effects. Multiple correlations of the log k values for the reactions of 6-substituted nicotinic acids and p-substituted benzoic acids in 12 alcohols with groups of suitable solvent parameters are very successful. The transmission of electronic effects through the pyridine ring system in compared with that in benzene.
Keywords: 6-substituted nicotinic acids, protic solvents, solvent parameters, Hammett correlation.

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J.Serb.Chem.Soc.65(7)491-496(2000)
UDC 547:92:547.56:547.554.5:533.73
JSCS-2768
Original scietific paper

Molecular orbital study of the oxidation of steroidal phenols into quinols and epoxyquinols

ZORAN MARKOVIC, BOGDAN SOLAJA*^,**, DRAGAN MILIC*^,**, IVAN JURANIC*, and MIROSLAV J. GASIC**

Chemistry Department, Faculty of Science, University of Kragujevac; Kragujevac,
*Faculty of Chemistry, University of Belgrade, P.O.Box 158, YU-11001 Belgrade and
**Institute of Chemistry, Technology and Metallurgy, Belgrade, Yugoslavia

(Received 29 July 1999)
The MO study showed that the radical oxidation of phenols into quinols occurs readily. Further radical oxidation (in the m-CPBA / (BzO)₂ /hn system) of quinols occurs through appropriate biradical species with an activation energy of 79.5 kJ/mol yielding syn-epoxyquinols. The stereochemical outcome presented in this study is in full agreement with the experimental results.
Keywords: steroids, phenols, quinols, epoxyquinols, oxidation MNDO-PM3 study.

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J.Serb.Chem.Soc. 65(7)497-505(2000)
UDC 547.473/.474:542.9
JSCS-2769
Original scientific paper

Synthesis of higher sugars as precursors for the synthesis of chiral polyhydroxylated macrocyclic lactones

MOMCILO MILJKOVIC and MARGARET HABASH-MARINO

Department of Biochemistry and Molecular Biology, The Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, PA 17033, USA

(Received 17 December 1999)
A general method for the synthesis of higher sugars that can be used as precursors for the synthesis of polyhydroxylated macrocyclic lactones (macrolides) was described. The extension of the carbohydrate chain of a hexopyranose was effected at its C(6) hydroxymethyl carbon by coupling of two carbohydrate precursors via Wittig reaction. In this way 6,7-dideoxy-2,3,4,5,8,9,10-hepta-O-methyl-11-O-triphenylme-thyl-D-arabino-D-glucoundecanose diethyl dithioacetal (1) was synthesized as a model compound.
Keywords: higher sugars, sugar chain elongation, Wittig reaction, sugar phosphonium salts, polyhydroxylated macrocyclic lactones.

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J.Serb.Chem.Soc. 65(7)507-515(2000)
UDC 546.73/541.132/:543.866:541.128
JSCS-2770
Original scientific paper

Chemical aspect of the influence of cobalt ions on ATPase activity

LJUBICA VUJISIC, DANIJELA KRSTIC and JOVAN VUCETIC*

Laboratory of Physical Chemistry, Vinca Institute of Nuclear Sciences, P. O. Box 522, YU-11001 Belgrade and
*Faculty of Chemistry, University of Belgrade, P. O. Box 158, YU-11001 Belgrade, Yugoslavia

(Received 15 October 1999)
The influence of Co²⁺ ions on the activities of Na⁺/K⁺-ATPase and Mg²⁺-ATPase, enzymes from rat brain synaptic plasma membrane, was studied. The aim of this study was to investigate the inhibition of both ATPases activities by exposure to cobalt ions as a function of experimentally added CoSO₄. The "free" Co²⁺ concentrations in the reaction mixture were also calculated and discussed. CoSO₄ induced a dose-dependent inhibition of both enzymes. The IC₅₀ values of Co²⁺, as calculated from the experimental curves, were 168 µM for Na⁺/K⁺-ATPase and 262 µM for Mg²⁺-ATPase, and for the recalculated free Co²⁺ concentration 75.4 µM for Na⁺/K⁺-ATPase and 136 µM for Mg²⁺-ATPase. The obtained linear Dixon's plot for Na⁺/K⁺-ATPase implies equilibium binding of cobalt with inhibitory sites on the enzyme. The kinetic parameters for both enzymes in presence and absence of CoSO₄ were calculated from the experimental data. The results of the kinetic analysis show that inhibition of Na⁺/K⁺-ATPase induced by CoSO₄ is non-competitive, and for Mg²⁺-ATPase that there are two sites of different sensitivities or two different enzymes.
Keywords: cobalt, Na⁺/K⁺-ATPase, Mg²⁺-ATPase, kinetics.

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J.Serb.Chem.Soc. 65(7)517-527(2000)
UDC 547.314.2:537.12:541.124.7
JSCS-2771
Original scientific paper

Total, direct and dissociative electron impact ionization cross sections of the acetylene molecule

GORAN JOSIFOV, DRAGAN LUKIC, NADA \URIC and MILAN KUREPA

Institute of Physics, P. O. Box 68, YU-11081 Belgrade, Yugoslavia

(Received 6 September 1999, revised 23 February 2000)
The total electron impact ionization cross sections of the acetylene molecule have been measured in the incident electron energy range from threshold to 1000 eV. These results are compared with other existing data, obtained by direct measurements of this molecular property or by indirect ones, via the partial ionization cross sections for the formation of different ions. Using three semiempirical equations, the total ionization cross sections were calculated and compared to available data, too. Direct and dissociative ionization cross sections were also calculated by a semiempirical equation and compared to existing data.
Keywords: electron, acetylene molecule, ionization, cross sections, dissociative ionization.

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J.Serb.Chem.Soc. 65(7)529-536(2000)
UDC 535.338:548.55:535.344
JSCS-2772
Short communication

SHORT COMMUNICATION
FT-IR reflection spectra of single crystals: resolving phonons of different symmetry without using polarised radiation

VLADIMIR M. PETRUSEVSKI, VLADIMIR IVANOVSKI and METODIJA NAJDOSKI

Istitute of Chemistry, Faculty of Science, "St. Cyril and Methodius" University, Arhimedova 5, P. O. Box 162, 91001 Skopje, Macedonia

(Received 28 October 1999, revised 17 January 2000)
Fourier-transform infrared (FT-IR) reflection spectra, asquired at nearnormal incidence, were recorded from single crystals belonging to six crystal systems: CsCr(SO₄)₂.12H₂O (alum, cubic), K₂CuCl₂·2H2O (Mitscherlichite, tetragonal), CaCO₃ (calcite, hexagonal), KHSO₄ (mercallite, orthorhombic), CaSO₄·2H₂O (gypsum, monoclinic) and CuSO₄·5H₂O (chalcantite, triclinic). The acquired IR reflection spectra were further transformed into absorption spectra, employing the Kramers-Kronig transformation. Except for the cubic alums, the spectra strongly depend on the crystal face from which they were recorded; this is a consequence of anisotropy. Phonons of a given symmetry (E-species, in tetragonal/hexagonal and B-species, in monoclinic crystals) may be resolved without using a polariser. The spectrum may be simplified in the case of an orthorhombic crystal, as well. The longitudinal-optical (LO) and transversal-optical (TO) mode frequencies were calculated in the case of optically isotropic and the simplified spectra of optically uniaxial crystals.
Keywords: reflection spectra, anisotropy, Kramers-Kronig transformation, phonons, symmetry resolving, LO phonons, TO phonons.

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J.Serb.Chem.Soc.65(7)537-541(2000)
UDC 546.733-/54-386/:547.415.1-547.293-547.295
JSCS-2773
Note

NOTE
Synthesis and characterization of meridional isomer of uns-cis-(ethylenediamine-N-N'-di-3-propionato)-(S-norleucinato)cobalt(III) semihydrate

TIBOR J. SABO and SRECKO R. TRIFUNOVIC*

Faculty of Chemistry, University of Belgrade, P. O. Box 158, Studentski trg 16, YU-11001 Belgrade, and
*Department of Chemistry, Faculty of Science, University of Kragujevac, P. O. Box 60, Radoja Domanovica 34, YU-34000 Kragujevac, Yugoslavia

(Received 30 July 1999)
The meridional geometrical isomer of uns-cis-(ethylenediamine-N-N'-di-3-propionato)(S-norleucinato)cobalt(III) complex has been prepared by the reaction of sodium uns-cis-(ethylenediamine-N-N'-di-3-propionato)(carbonato)cobaltate(III) with S-norleucine at 75°C. The complex was isolated choromatographically and characterized by elemental analyses, electron absorption and infrared spectroscopy.
Keywords: cobalt(III) complexes, ethylenediamine-N-N'-di-3-propionic acid, S-norleucine.

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