JSCS Vol 69, No. 4
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Impresum |
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J.Serb.Chem.Soc.
69(4)239–245(2004) |
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Facile rearrangement of
push-pull 5-substituted 4-oxothiazolidines induced by pyridinium hydrobromide
perbromide under homogeneous reaction conditions
RADE MARKOVIC*,**, MARIJA BARANAC*,**
and ZDRAVKO DZAMBASKI**
*Faculty of Chemistry,
University of Belgrade, Studentski trg 16, P.O. Box 158, 11000 Belgrade
**Center for Chemistry
ICTM, P.O.Box 473, 11000 Belgrade, Serbia and Montenegro
(Received 3 October
2003)
Pyridinium hydrobromide perbromide (PHBP) is a
highly efficient reagent for the conversion of
5-substituted-2-alkylidene-4-oxothiazolidine derivatives to the corresponding
thiazolidines with two fully delocalized exocyclic double bonds at the C(2) and
C(5) positions. This conversion as a two-step bromination-rearrangement process
occurs in acetonitrile under homogeneous reaction conditions.
Keywords: thiazolidine, rearrangement, pyridinium hydrobromide perbromide,
acetonitrile.
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J.Serb.Chem.Soc.
69(4)247–254(2004) |
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An expeditious synthesis of 3,4-dihydrobenzo[2,3-d]pyrimidines using inorganic
solid supports
MAZAAHIR KIDWAI and AKKAL DEO MISHRA
Department of Chemistry,
University of Delhi, Delhi-110007, India
(Received 4 September
2003)
A series of novel
5-substituted-8-cyano-4,6,7-triphenyl-3,4-dihydrobenzo [2,3-d]pyrimidines
were synthesized by the condensation of
6-substituted-2-AMino-1-benzoyl-3-cyano-5-hydroxy-4,5-diphenyl-1,3-cyclohexadiene
and formAMide, using inorganic solid supports under microwaves. Some of the
compounds were found to be effective against some fungal and bacterial strains.
Keywords: benzopyrimidines, inorganic solid supports, microwave,
environmentally benign synthesis, antimicrobial.
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J.Serb.Chem.Soc.
69(4)255–264(2004) |
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Physico-chemical studies of some AMinobenzoic acid hydrazide complexes
M. G. ABD EL WAHED, S. ABD EL WANEES, M. EL
GAMEL and S. ABD EL HALEEM
Faculty of Science,
Zagazig University, Zagazig, Egypt
(Received 2 September,
revised 19 November 2003)
The stability constants and related
thermodynAMic functions characterizing the formation of divalent Ni, Cu, Zn, Cd
and Hg complexes with o- and p-AMinobenzoic acid hydrazide were
determined potentiometrically at different temperatures. The formations of the
complexes are endothermic processes. The formed bonds are mainly electrostatic.
Conductometric titration was carried out to determine the stoichiometry and
stability of the formed complexes. The structures of complexes were
characterized by their IR, 1H-NMR and 13C-NMR spectra, as
well as X-ray diffractogrAMs. The coordination process takes place through the
carbonyl group and the terminal hydrazinic AMino group. The thermal stability
of the complexes was followed in the temperature range 20–600ºC.
Keywords: potentiometry, conductometry, stability constants, thermodynAMic
parAMeters, structure and thermal stability of complexes.
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J.Serb.Chem.Soc.
69(4)265–271(2004) |
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On the relation between Zenkevich and Wiener
indices of alkanes
IVAN GUTMAN, BORIS FURTULA, BILJANA ARSIC and
ZARKO BOSKOVIC
Faculty of Science,
University of Kragujevac, P.O. Box 60, 34000 Kragujevac, and
*Faculty of Science, University of Nis, Vi{egradska 33, 18000 Nis, Serbia and
Montenegro
(Received 4 November
2003)
A relatively complicated relation was found to
exist between the quantity U, recently introduced by Zenkevich
(providing a measure of internal molecular energy), and the Wiener index W
(measuring molecular surface area and intermolecular forces). We now report a
detailed analysis of this relation and show that, in the case of alkanes, its
main features are reproduced by the formula U = –aW + b + gn1; where n1 is the number of methyl groups, and a, b and g are constants, depending only on the number of carbon atoms.
Thus, for isomeric alkanes with the sAMe number of methyl groups, U and W
are linearly correlated.
Keywords: Zenkevich index, Wiener index, alkanes.
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J.Serb.Chem.Soc.
69(4)273–281(2004) |
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Physicochemical and structural characteristics
of HEU-type zeolitic tuff treated by hydrochloric acid
ANA RADOSAVLJEVIC-MIHAJLOVIC, VERA DONDUR,
ALEKSANDRA DAKOVIC, JOVAN LEMIC and
MAGDALENA TOMASEVIC-CANOVIC
Institute for Technology of Nuclear and Other Mineral Raw Materials, Applied
Physical Chemistry Unit, P.O. Box 390,
86 Franchet d’Esperey Street, 11000 Belgrade, and
*Faculty of Physical Chemistry, P.O. Box 137, 11000 Belgrade, Serbia and
Montenegro
(Received 27 August,
revised 18 November 2003)
SAMples of natural
HEU-type zeolites – clinoptilolite-Ca, from the Novakovici deposit (near
Prijedor, Bosnia and Herzegovina) were treated with the hydrochloric acid of
various concentrations (from 10-3 M to 2 M). Zeolitic tuffs before
and after the acid treatment were exAMined using IR, XRPD, and chemical
analyses. The changes in the crystal structure of acid treated sAMples showed a
significant reduction in the crystallinity of zeolitic tuffs (60–70 %), which
were effected by hydrochloric acid with concentrations of 1 M and above.
Keywords: HEU-type zeolite, acid modification, X-ray analysis, Novakovici.
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J.Serb.Chem.Soc.
69(4)283–298(2004) |
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Selective liquid-liquid extraction of
antimony(III) from hydrochloric acid media by N-n-octylaniline in xylene
B. M. SARGAR, M. M. RAJMANE and M. A. ANUSE
Analytical Chemistry Laboratory, Department of Chemistry, Shivaji
University, Kolhapur-416 004, India
(Received 2 June 2003)
N-n-Octylaniline in xylene was used for the
extraction separation of antimony(III) from hydrochloric acid media.
Antimony(III) was extracted quantitatively with 10 mL 4 % N-n-octylaniline
in xylene. It was stripped from the organic phase with 0.5 M AMmonia and
estimated photometrically by the iodide method. The effect of metal ion, acid,
reagent concentration and various foreign ions was investigated. The method
affords binary and ternary separation of antimony(III) from tellurium(IV),
selenium(IV), lead(II), bismuth(III), tin(IV), germanium(IV), copper(II),
gold(III), iron(III) and zinc(II). The method is applicable for the analysis of
synthetic mixtures, alloys and semiconductor thin films. It is fast, accurate
and precise.
Keywords: antimony(III), N-n-octylaniline, solvent extraction.
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J.Serb.Chem.Soc.
69(4)299–307(2004) |
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Pectinases partitioning in aqueous two-phase systems: an integration of
the systems poly(ethylene glycol)/crude dextran and poly(ethylene
glycol)/AMmonium sulphate
MIRJANA G. ANTOV DRAGINJA M. PERICIN and STANA
N. PEJIN
Faculty of Technology, University of Novi Sad, Blvd. Cara Lazara 1, 21000
Novi Sad, Serbia and Montenegro
(Received 4 November
2003)
The partitioning of pectinases in the
poly(ethylene glucol)4000/AMmonium sulpohate system was studied and also its
application for enzymes extraction from the top phase of the poly(ethylene
glucol)4000/crude dextran system. Almost complete one-sided partition of
endo-pectinase and exo-pectinase to the bottom phase of the polymer/salt system
was achieved at a tie-line length of 37.16 %. The concentration factors were
1.73 and 3.25, respectively. The highest total endo- and exo-pectinase yields
(72.41 % and 69.46 %, respectively) were obtained by integration of the
polymer/polymer system at a tie-line of 8.61 % and a high phase volume ratio
and the polymer/salt system at a tie-line of 30.23 % and a low phase volume
ratio. Integration of the partitioning at a high tie-line length in the
polymer/polimer and a low tie-line length in the polymer/salt system resulted
in a total concentration factor of 1.5 and a purification of 1.66 fold for
exo-pectinase. The addition of phosphate to this integrated system improved the
total concentration factor and purification fold of the activity to 1.73 and
2.14, respectively.
Keywords: aqueous two-phase system, partitioning, pectinases.
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J.Serb.Chem.Soc.
69(4)309–317(2004) |
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Sorption-spectrophotometric method for the determination of Pd(II) in aqueous
solutions
VESNA VASIC, JASMINA SAVIC, NIKOLA VUKELIC*
Department of Physical
Chemistry, Vinca Institute of Nuclear Sciences, P.O. Box 522,
*Faculty of Physical Chemistry, Belgrade University, P. O. Box 137, 11001
Belgrade, Serbia and Montenegro
(Received 3 June,
revised 24 November 2003)
The reaction of Pd(II) with
1,8-dihydroxy-2-(pyrazol-5-ylazo)-naphthalene-3-6-disulphonic acid (PACA)
sorbed onto Dowex 1-X8 ion-exchange resin was investigated with the aim of
developing an absorption-spectrophotometric analytical method for the
determination of low Pd(II) concentrations in water. The immobilized reagent
formed a 1:1 complex with Pd(II) having an absorption maximum at 650 nm.
ParAMeters, such as pH, wavelength and contact time were optimised for a given AMount
of the sorbed reagent. The linearity range of absorbance vs. Pd(II)
concentration extended from 5×10-6 – 5×10-5 M, 5×10-7
– 5×10-6 and 2.5×10-8 – 2.5×10-7 M when using
10, 100 and 200 ml of sAMple solution, respectively. With a 200 ml sAMple, the
detection limit was 2.5×10-7 M Pd(II). Most metals, except Cu(II),
did not interfere when present in up to 100 times the concentration of Pd(II).
Keywords: azo-dyes, immobilization, ion-exchangers, ion-exchange
colorimetry, palladium.
Copyright &AMp; copy; SHD 2004.
June 24, 2004.
For
more information contact: SHD@tmf.bg.ac.yu