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Condensation of 1,3-diketones with cyanoacetamide: 4,6-disubstituted-3-cyano-2-pyridones
MILICA MISIC-VUKOVIC, DUSAN MIJIN, MIRJANA RADOJKOVIC-VELICKOVIC, NATASA VALENTIC and VERA KRSTIC
Department of Organic Chemistry, Faculty of
Technology and Metallurgy, University of Belgrade,
P.O.Box 494, YU-11001 Belgrade, Yugoslavia
2. Results and discussion
3. Selectivity of the reaction
4. Kinetics and mechanism of the reaction
5. Enzyme catalyzed reactions
6. Structure-activity relationships
7. Further investigations
Key words: 1,3-diketones, substituted 3-cyano-2-pyridones, catalysis, enzymes, ion-exchange resins, phase-transfer catalysts, kinetics of condensation.
A facile synthesis and some new reactions of N-benzylcarboxamides with essential amino acids
RAGAB A. EL-SAYED
Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egypt
(Received 13 June 1997, revised 26 March 1998)
N-Benzyl-p-chloro and N-benzyl-2,4-dichlorobenzamide react with chlorosulfonic acid to give the corresponding p-sulfonyl chlorides (I, XIX), which on condensation with nucleophiles give amino acid derivatives (II-VII) and (XX-XXV). Some of the corresponding methyl esters (VIII-XI) were also prepared. Hydrazinolysis of these methyl esters yielded the hydrazides (XII-XV). Coupling reactions of some amino acid derivatives with amino acid methyl ester hydrochloride in THF-Et3N medium, using the dicylohexylcarbodiimide method, furnished the desired dipeptide methyl esters (XVI-XVII), (XXVI-XXVIII). The spectral data are briefly discussed.
Key words: chlorosulfonation of N-benzyl-4-chlorobenzamide, N-benzyl-2,4-dichlorobenzamide and their reactions with different essential amino acids.
J. Serb. Chem. Soc. 63(8) 607-611 (1998)
Original scientific paper
A facile route for synthesis of some novel organosulfur amino acid derivatives
RAGAB A. EL-SAYED
Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo, Egyipt
June 1997, revised 26 March 1998)
The synthesis of a series of 4-chlorocinnamanilide-4'-sulfonylamino acids (II-VIII), and some of the corresponding amino acid methyl esters (IX-XIII), and hydrazides (XIV-XVI) are described. Coupling reactions of the 4-chlorocinnamanilide-4'-sulfonylamino acids with amino acid methyl ester hydrochlorides in a THF-Et3N medium, using the dicyclohexylcarbodiimide method, gave the dipeptide methyl esters (XVII-XIX). The spectral data of some selected compounds are briefly discussed.
Key words: coupling reactions, amino acids, methyl esters, hydrazides, dipeptide derivatives.
Classification of the asphalts and their source rock from the Dead Sea Basin (Israel): the asphaltene/kerogen vanadyl porphyrins
I. PREMOVIC, IVANA R. TONSA, MIRJANA S. PAVLOVIC* and
LJUBISA S. JOVANOVIC
Laboratory for Geochemistry and Cosmochemistry,
Department of Chemistry, Faculty of Science,
University of Nis, P. O. Box 91, YU-18000 Nis, Yugoslavia and
*Institute of Nuclear Sciences Vinca P.O. Box 522, YU-11000 Belgrade, Yugoslavia
30 January, revised 30 March 1998)
The asphaltenes of the asphalts from the Dead Sea Basin were examined for the presence of vanadyl porphyrins. These examinaitons demonstrated that the asphalts fall into two broad class types, one having a relatively high vanadyl prophyrins content (>300 ppm) and the other characterized by no vanadyl porphyrins (<10 ppm). It is concluded that these asphalts belong to two genetic types and have separate origins. The kerogens isolated from the petroleum-source rock of the Dead Sea Basin were also analyzed. Two genetic types of kerogen appeared to exist, a marine one highly enriched with these pigments and a terrestrial one with no vanadyl porphyrins. For comparison, the asphaltenes of typical asphaltic crude oils from Western Venezuela and kerogen from their La Luna source rock were also examined. Previous detailed geochemical studies1 indicated that La Luna kerogen is derived from marine organic matter source. These materials have higher concentrations of vanadyl porphyrins than the Dead Sea asphaltenes and the kerogens are enriched with these compounds. Our results strengthen the potential of vanadyl porphyrins of both petroleum asphaltenes and source-rock kerogen for use in genetic and correlation studies.
Key words: asphalt, vanadyl porphyrins, kerogen, petroleum.
Some biochemical characteristics of three industrial Penicillium chrysogenum strains
LJUBINKA GLIGIC, MARJETKA KIDRIC* and JELENA JOKSIMOVIC**
ICN-Yugoslavia Pharmaceutical Works, Belgrade,
*Jozef Stefan Institute, Ljubljana, Slovenia and
**Institute for Biological Research, YU-11060 Belgrade, Yugoslavia
24 November 1997)
Comparative studies of the three high-producing industrial P. chrysogenum strains of different origin and capacity for penicillin synthesis, designated M-7, M-8 and M-9, were performed. The uptake of phenoxyacetic acid (POA), as a precursor of the side chain in the penicilin V molecule, and the synthesis of the antibiotic were examined by HPLC analysis during 7 days of batch-type fermentation. The uptake of POA during the fermentation proceeded in several phases. The duration of each phase, as well as the extent of the precursor uptake varied in a strain-specific way. More intensive uptakes of POA were recorded during the periods when the fermentation broth had lower pH values. Different fluctuations in the penicillin production between the three strains were observed. The M-8 and M-9 strains were more efficient with respect to both the POA uptake and penicillin production than the M-7 strain. The highest penicillin production activity of the M-8 and M-9 strains was recorded between 96 and 120 h of fermentation and that of the M-7 strain occured some 24 h later. In all three strains an intensive uptake of the precursor preceded the periods of intensive penicillin synthesis. The content of the total ribonucleic acids (RNAs) in the mycelium, as an indicator of metabolically active biomass, varied during the fermentation in a strain-specific manner. In all three P. chrysogenum strains the maximum RNA content preceded periods of intensive penicillin V biosynthesis. The relative mycelium volume (RMV) and the dry weight increased continually during the fermentation suggesting that the RNA content represents a much more reliable indicator of the metabolically active biomass than the former two values, usually employed as references in fermentation processes.
Key words: Penicillium chrysogenum, phenoxyacetic acid, penicillin V, batch-type fermentation, RNA.
The fatty acid composition of Dysidea fragilis from the Black Sea and Adriatic Sea
IVAYLO J. ELENKOV, KAMEN L. STEFANOV, ZORAN KLJAJIC*, NIKOLA DOGOVIC**, MIROSLAV J. GASIC** and SIMEON S. POPOV
Institute of Organic Chemistry with Center of
Phytochemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria,
*Institute for Marine Biology, Kotor, Yugoslavia and
**Faculty of Chemistry, University of Belgrade, P.O. Box 158, YU-11001 Belgrade, Yugoslavia
24 March 1998)
The fatty acid compositions of the sponge Dysidea fragilis from the Black Sea and the Adriatic sea, collected at different depths and salinity were investigated and the effect of these environmental factors are discussed. The fatty acids from an Adriatic sponge sample Pellina semitubulosa were also investigated.
Key words: fatty acids, sponges, Dysidea fragilis, Pellina semitubulosa.
Approximating total p-electron energy in terms of spectral moments. A quantitative approach
GUTMAN, SVETLANA MARKOVIC, ALEKSANDAR VESOVIC and ERNESTO ESTRADA*
Faculty of Science, University of Kragujevac, P.O.Box 60, YU-34000 Kragujevac, Yugoslavia, and
*Universidad Central de Las Villas, Santa Clara 54830, Villa Clara, Cuba
23 March 1998)
The idea to expand the total p-electron energy in terms of spectral moments was put forward already in the 1950s, but its quantitative testing has not yet been accomplished. We now provide results aimed at filling this gap. The total p-electron energy of benzenoid hydrocarbons is approximated by means of a linear combination of the first few spectral moments. The accuracy of this approximation is very good (relative errors below 0.1%, correlation coefficients above 0.99995). Inclusion of spectral moments higher than the tenth does not significantly improve the quality of the approximation. Expanding the total p-electron energy in terms of spectral moments of the line graph yields very similar or identical results.
Key words: total p-electron energy, spectral moments, benzenoid hydrocarbons.
A note on Cluj weighted adjacency matrices
Jurkovicova 13, 63800 Brno, Czech Republic
January, revised 30 March 1998)
The assymmetric Cluj matrices of trees are obtained by splitting the scalar products of the path vertex matrices of the tree with the corresponding incidence matrix of the unoriented complete graph into a diagonal matrix and an off-diagonal Cluj matrix. The Wiener number appears at the xn-2 term of the characteristic polynomial of the direct product of the Cluj matrix with the corresponding adjacency matrix.
Key words: Wienner number, adjacency matrices, Cluj matrices, eigenvalues, characteristic polynomials.
Ammonia adsorption on chemically modified activated carbon cloth
MIRJANA POLOVINA, BRANKA KALUDJEROVIC, BILJANA BABIC
Vinca Institute of Nuclear Sciences, Laboratory 170, P.O.Box 522, YU-11001 Belgrade, Yugoslavia
13 February 1998)
The effect of CuCl2, CuSO4, and H2SO4 impregnation of activated carbon cloth on ammonia adsorption at 303 K were examined. Cellulose based activated carbon cloth of various activities were used as the starting materials. The carbon cloth surface area and porous structure parameters were determined by N2 adsorption at 77 K using the gravimetric McBain method. Ammonia adsorption was significantly increased on impregnated samples, at low relative pressure (low NH3 concentration). Ammonia adsorption at high concentration was found to be directly influenced by the available micropore valume of the activated carbon cloth.
Key words: activated carbon cloth, impregnation, ammonia adsorption.
Ternary and quaternary zinc-antimony based spinels
DEJAN POLETI, and LJILJANA KARANOVIC*
Department of General and Inorganic Chemistry,
Faculty of Technology and Metallurgy, P.O.Box 494, YU-11001 Belgrade, and
*Laboratory for Crystallography, Faculty of Mining and Geology, Djusina 7, YU-11000 Belgrade, Yugoslavia
Several series of ternary, ZnxMzSbyO4, and quaternary, ZnxMz1'Mz2''SbyO4, spinels, where M', M'' = Co2+, Ni2+, Mn3+ and Cr3+, have been prepared by solid state reactions at 1100-1200°C. A compelte range of solid solutions was found to exist in only one case, between Zn2.333Sb0.667O4 and Co2.333Sb0.667O4 as end-members. The samples were characterized by X-ray diffraction and diffuse reflectance spectroscopy. The lattice parameters of both the ternary and quaternary spinels depend linearly on the transition metal content. The diffuse reflectance spectra indicate that for y << 1.33 (or y1+y2 < 1.33) the tetrahedral sites are fully occupied by Zn2+ ions.
Key words: spinels, zinc-antimony spinels, transition metals, cell parameters, cation distribution.
The preparation and characterization of facial and meridional isomers of uns-cis-(ethylenediamine-N,N'-di-3-propionato) cobalt(III) complexes with aliphatic a-S-amino acids
SANJA R. GRGURIC, SRECKO R. TRIFUNOVIC* and TIBOR J. SABO
Faculty of Chemistry, University of Belgrade,
P.O.Box 158, YU-11001 Belgrade and
*Department of Chemistry, Faculty of Science, University of Kragujevac, P.O.Box 60, YU-34000 Kragujevac, Yugoslavia
28 December 1997, revised 23 March 1998)
A series of several complex compounds, both facial and meridional, of uns-cis-(ethylenediamine-N,N'-di-3-propionato)cobalt(III) complexes with some a-S-amino acids, S-alanine, S-valine, S-leucine and S-isoleucine, were prepared by the reaction of sodium uns-cis-(ethylenediamine-N,N'-di-3-propionato)(carbonato)cobaltate(III)dihydrate and the corresponding amino acid at 70 °C. The complexes were isolated chromatographically and characterized by elemental analysis, as well as electron absorption and infrared spectroscopy.
Key words: cobalt(III) complexes, ethylenediamine-N,N'-di-3-propionic acid, S-amino acid.
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Last Updated July 20, 1998
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