J. Serb. Chem. Soc. 62
(12) 1143-1149(1997)
UDC 66.095.252:547.265
JSCS-2486
Original
scientific paper
Intramolecular cyclisation of 4-tert-butyl-penten-1-ol
with electrophilic reagents 1-3
MIHAILO Lj. MIHAILOVIC, SVETISLAV GOJKOVIC*, SLOBODAN
MILOSAVLJEVIC
and STANIMIR KONSTANTINOVIC**
Faculty of Chemistry, University of Belgrade, Studentski trg
12-16, P.O.Box 158, YU-11001 Belgrade, Yugoslavia,
*Institute of Chemistry, Technology and Metallurgy,
Njegoseva 12, YU-11000 Belgrade, Yugoslavia,
**Department of Chemistry, Faculty of
Science, University of Kragujevac, P. O. Box 60, YU-34000 Kragujevac,
Yugoslavia
(Received
16 May 1997)
In the acid (H2SO4) catalysed reaction of
4-tert-butyl-4-penten-1-ol (3), the products of 1,2-methyl
rearrangement were obtained (the tetrahydripyran-type ether 8 and the
aldehyde 9). The "normal" and rearranged cyclisation products 7
and 8 were formed in approximately equal amounts (34% and 36%,
respectively), while the open-chain aldehyde with a rearranged skeleton 9
was also formed in significant yield (29%). The oxymercuration/demercuration
reaction of 3 and its reaction with meta-chloroperbenzoic acid afforded
in high yields exclusively Markovnikov-type products, i.e., the THF
ether 7 and the THF-hydroxy ether 17.
Key
words: intramolecular cyclisation, 4-tert-butyl-4-pentenl-ol, electrophilic
regents.
J. Serb. Chem. Soc. 62(12) 1151-1156 (1997)
UDC
547.514.71:542.9
JSCS-2487
Original
scientific paper
A simple synthetic route to 2,2,5-trimethyl-4-cyclohepten-1-one (karahanaenone)
starting with linalool
STANIMIR KONSTANTINOVIC* **, ZORICA BUGARCIC*, LJILJANA
MARJANOVIC*,
SVETISLAV GOJKOVIC***, and MIHAILO LJ. MIHAILOVIC*** ****
*Department of Chemistry, Faculty of Science, University of
Kragujevac, P.O.Box 60, YU-34000 Kragujevac, Yugoslavia,
**Max-Planc-Institut fuer Kohlenforschung,
P.O.Box 101353, D-45466, Muelheim - Ruhr, Germany,
***Institute of Chemistry, Technology and
Metallurgy, Njegoseva 12, YU-11000 Belgrade,
****Faculty of Chemistry, University of Belgrade,
P.O.Box 158, YU-11001 Belgrade, Yugoslavia
(Received
2 July 1997)
2,2,5-Trimethyl-4-cyclopten-1-one
(karahanaenone) (1) has been prepared from linalool (3) was
cyclized to the corresponding tetrahydrofuran-type cyclic ether 4 by
means of PhSeCl, N-bromosuccinimide, or 3-chloropenbenzoic acid. On
treatment with various regents, the cyclic ether 4 provided the cyclic
ether 6 which was converted to 1 via 2.
Key
words: karahanaenone synthesis of, linalool, PhSeCl, NBS, 3-chloroperbenzoic
acid.
J. Serb. Chem. Soc. 62(12) 1157-1165 (1997)
UDC
547.514.71:543.42/.51
JSCS-2488
Original
scientific paper
Studies of ferrocene derivatives. IV. Synthesis and NMR spectra
of some (1-hydfroxy-w-alkenyl)-and
(1-hydroxy-1-methil-w-alkenyl) ferrocenes 1,2
STANIMIR KONSTANTINOVIC, SVETLANA SIMOVA* ZORAN RATKOVIC
and JASMINA PREDOJEVIC
Department of Chemistry, Faculty of Science, University of
Kragujevac, P.O. Box 60,
YU-34000 Kragujevac, Yugoslavia and
*Institute of Organic Chemistry, Bulgarian
Academy of Sciences, 1113 Sofia, Bulgaria
(Received
9 May 1997)
(1-Hydroxy-w-alkenyl)-
and (1-hydroxy-1-methyl -w -alkenyl) ferrocenes have been
synthesised and their high resolution 1H, and 13C-NMR spectra studied in view of the stereochemistry of a
substituent connected to cyclopentadienyl ring. It is found that when these
substituted ferrocene derivatives contain in the substituent a chiral center,
the 2,3- and 3,4-positions in the cyclopentadienyl ring become pairwise
diastereotopic and magnetically unequivalent.
Key
words: (1-hydroxy-w-alkenyl)- and
(1-hydroxy-methyl-w-alkenyl) ferrocenes,
synthesis, NMR spectra
J. Serb. Chem. Soc. 62(12) 1167-1174 (1997)
UDC
547.852.7:547.462.3:543.51
JSCS-2489
Original
scientific paper
Stereochemistry of the cycloaddition reaction of
1-metyl-phthalazinium ylids to maleic and fumaric esters
STEFAN DIMA*, IONEL MANGALAGIU, MARIA CAPROSU and MAGDA
PETROVANU
Al. I. Cuza University Iasi, Faculty of Chemistry, Organic
Chemictry Department,
B-dul Copou, Nr.11, IASI-6600, Romania, and
*Dunarea de Jos University Galati, Faculty
of Sciences, Chemistry Department,
Str. Domneasca, Nr.47, GALATI-6200, Romania
(Received
12 March, revised 12 August 1997)
For the first time in the phthalazinium
ylids series we have a theoretical and experimental study concerning the
stereochemistry of the 3+2 dipolar cycloaddition reaction of these ylids to
symmetrically substituted cis-trans olefines. It has been proved that
the cycloaddition reactions are mostly cis-stereospecific. A possible
reaction mechanism is presented. Eight new pyrollophthalazine heterocycles have
been obtained.
Key
words: phthalazine, ylids, cycloaddition, stereochemistry.
J. Serb. Chem. Soc. 62(12) 1175-1182 (1997)
UDC 547.854/.4
JSCS-2490
Original
scientific paper
Reactivity of 3-N-(4-substituted phenyl)-5-carboxy
uracils
N. V. VALENTIC, M. RADOJKOVIC-VELICKOVIC, M. MISIC-VUKOVIC and
G. USCUMLIC
Faculty of Technology and Metallurgy, University of Belgrade,
Karnegijeva 4,
P.O.Box 494, YU-11001 Belgrade, Yugoslavia
(Received
27 July 1997)
The effect of various phenyl substituents
on the reactivity of the carboxy groups of 3-N-(4-substituted
phenyl)-5-carboxy uracils has been investigated. The substitutents at the
phenyl nucleus were as follows: H, Br, I, NO2, OMe. The rate constants of the investigated acids in their
reaction with diasodiphenylmethane (DDM) were determined in methanol and in
ethanol at 30°C, using the known spectrophotometric method. The obtained
kinetic data, as well as the values of the IR stretching vibrations of the
principals of linear free energy correlations. Considering that the substituted
phenyl group resides at the nitrogen atom, having two carbonyl groups as ortho
substituents, it is very probable that the effect of the substituents in
position 4 of the phenyl nucleus is influenced by resonance interactions
between the nitrogen electron pair, the carbonyl groups and the substituent
itself. The polarity of the reaction medium also affects the complex resonance
interactions in the molecules of the investigated compounds.
Key
words: 3-N-(4-substituted phenyl)-5-carboxy uracils, diazodiphenylmethane,
transmission of substituent effects, solvent effects.
J. Serb. Chem. Soc. 62(12) 1183-1186 (1997)
UDC
66.094.1/.18:656.762.2(546.98)
JSCS-2491
Original
scientific paper
Hydriding and dehydriding of a graphite powder doped with
palladium
MILENKO V. SUSIC
Serbian Academy of Sciences and Arts and the Faculty of Physical
Chemistry,
University of Belgrade, Studentski trg 16,
YU-11000 Belgrade, Yugoslavia
(Received
1 July 1997)
The hydriding and dehydriding process of a
graphite powder doped with palladium was investigated. It was shown that, based
on the spillover hydrogen effect the graphite powder is transformed into a very
active hydrogen absorber. Kinetic and thermodynamic investigations of the
hydriding and dehydriding processes have been conducted. The activation energy
of the hydriding process and the enthalpies of the hydriding and dehydriding
processes have been determined. The absorbed hydrogen and absorber (R)
ratio has been determined and it has been shown that the prepared powder
graphite acts as a very active hydrogen absorber.
Key
words: Hydriding and dehydriding of graphite, spillover hydrogen
effect.
J. Serb. Chem. Soc. 62(12) 1187-1193 (1997)
UDC
547.497.1:546.73:541.428.79
JSCS-2492
Original
scientific paper
The solvent dependence of the electron transfer reaction between
the trans-dichlorobis (1,2-diaminoethane)cobalt(III) complex and
hexacyanoferrate(II) in binary solvent mixtures
KUPPANAGOUNDER PITCHAIMUTHU ELANGO, KRISHNAMOORTHY ANBALAGAN*
and GOPALAKRISHNAN KARTHIKEYAN*
Department of Chemistry, Gandhigram Rural Institute, Gandhigram
624 302, Tamil Nadu, India
(Received
16 May, revised 12 August 1997)
The electron transfer reaction between
trans-dichlorbis(1,2-diaminoethane)cobalt(III) ion and hexacyanoferrate(II),
which proceeds via the formation of a precursor complex, has been investigated
in aqueous mixtures of methanol, ethanol, tert-butanol and 1,4-dioxan.
The association constant of the formation of the precursor complex and the rate
constant for the electron transfer step have been experimentally determined in
these binary solvent mixtures. The reaction was carried out at three different
temperatures and the activation parameters have been computed. The effect of
the solvent on the reaction rate has been analysed in the light of various
solvent parameters.
Key
words: cobalt(III), reduction, solvent effect, iron(II).
J. Serb. Chem. Soc. 62(12) 1195-1200 (1997)
UDC
547.413.1:678.742:66.049
JSCS-2493
Original
scientific paper
Phase separation in the ethylene-polyethylene system at high
pressures. XII. Calculation of the solubility of ethylene in polyethylene using
the PHC theory
VOJISLAV Z.BOGDANOVIC, ALEKSANDAR Z. TASIC*, BOJAN D.
DJORDJEVIC* and
ZAGORKA M. KOJIC
Hemijska industrija Pancevo, YU-26000 Pancevo and
*Faculty of Technology and Metallurgy,
University of Belgrade, Karnegijeva 4, P.O. Box 494, YU-11001 Belgrade, Yugoslavia
(Received
17 February, revised 24 July 1997)
The perturbed-hard-chain (PHC) theory was
used to calculate the solubility values of ethylene in polyethylene at 403.15 K
in the pressure range of 20-140 MPa, and the specific volumes of ethylene
and polyethylene in the wide temperature and pressure ranges 375.15-471.15 K
and 20-140 MPa, respectively. The procedure for these computation was presented
in the preceding parts of the series of papers. The results obtained in the
present work are in good agreement with other experimental and predicted
values.
Key
words: system ethylene polyethylene; PHC theory; specific volune; solubility
of ethylene; high pressure.
J. Serb. Chem. Soc. 62(12) 1201-1212 (1997)
UDC 541.124.7:537.6
JSCS-2494
Original
scientific paper
Analysis of impedance data with dispersing effect by using the
linear least squares regression method
HOUYI MA, SHENHAO CHEN, XIAOLIANG CHEN, XIAO CHEN, GUIQIU LI*
and
XUDONG YANG*
Department of Chemistry, Shandong University and
*Department of Photo-Electronic Information
Engineering, Shandong University Jinan, 250100, P.R. China
(Received
10 April 1997)
In the presence of the dispersing effect,
the impedance of a double-layer behaves as a Constant Phase Element (CPE)
rather than as an ideal capacitor. In this paper, the origin of the dispersing
effect is satisfactorily accounted for by combining the CPE and the resistance
element. The derived impedance expression for a single dispersing capacitive
arc is consistent with the Cole-Cole formula. According to the manifestation of
the dispersing effect in impedance (or admittance) complex planes, several
linear relations have been proposed to calculate accurately and conveniently
the electrochemical parameters from a single dispersing sapacitive loop using
the linear least squares regression method. The method has also been applied to
the analysis of inductive loops, as well as more complicated EIS.
Key
words: dispersing effect, electrochemical impedance spectroscopy (EIS),
constant phase element (CPE), double-layer, circuit description code
(CDC).
J. Serb. Chem. Soc. 62(12) 1213-1220 (1997)
UDC 546.193'
863'':543.257.1
JSCS-2495
Original
scientific paper
Potntiometric and bipotentiometric determination of arsenic(III)
and antimony(III) with dichromate in acidic solutions
VOJKA V. ANTONIJEVIC, SNEZANA D. NIKOLIC-MANDIC and TIBOR
J.PASTOR
Faculty of Chemistry, University of
Belgrade, Studentski trg 16, P.O.Boz 158, YU-11001 Belgrade Yugoslavia
(Received
4 April, revised 9 July 1997)
The influence of iodine, iodide, iodate and
manganese(II), as well as the pretreatment of the platinum electrode, on the
potentiometric determination of arsenic(III) and antimony(III) with dichromate
in sulphuric and hydrochloric acid solutions, respectively, has been
investigated. The bipotentiometric curves obtained during the determination of
arsenic(III) with dichromate in 2.0-5.0 mol. dm-3 sulphuric acid
solutions, indicate the presence of two reversible redox pairs in the solution.
The redox systems As(V)/As(III) in 1.0-5.0 mol dm-3 hydrochloric acid
solutions and Sb(V)/Sb(III) in 1.0-5.0 mol dm-3 sulphuric acid
solutions are irreversible. Antimony(III) cannot be determined by the
bipotentiometric method in hydrochloric acid solutions. A decrease in the
polarization current of the indicator electrodes and an increase in the
concentration of the acid lead to more pronounced potential difference changes
at the end-point. Under optimal working conditions, the errors in the
potentiometric and bipotentiometric determination of samples containing 15-40
mg of arsenic(III) or 25-60 mg of antimony(III) are not greater than ± 1.5%.
Key
words: arsenic(III), antimony(III), dichromate, potentiometric and
bipotentiometric titrations, induced reaction.
J. Serb. Chem. Soc. 62(12) 1221-1225 (1997)
UDC 615.779:543.544
JSCS-2496
Original
scientific paper
High performance liquid chromatographic determination of
lincomycin in pharmaceutical formulations
SOTE VLADIMIROV, LJILJANA MARKOVIC*, DANICA AGBABA, DOBRILA
ZIVANOV-STAKIC and JASMINA BRBORIC
Department of Pharmaceutical Chemistry, Faculty of Pharmacy,
P.O.Box 146, Vojvode Stepe 450,
YU-11152 Belgrade and
*Department of Pharmacy, Vojvode Stepe 458,
YU-11152 Belgrade, Yugoslavia
(Received
10 April 1997)
A specific and simple HPLC procedure has
been developed, suitable for the determination of lincomycin hydrochloride
monohydrate (LNHC) in pharmaceutical formations. Rp-HPLC analysis was performed
with a LCD-Analytical Costa Metric 3000 system, equipped with Spectro Monitor
3100 UV/VIS detector. The lincomycin assay procedures were carried out on a
Supelcosil® LC-18-DB- (250×4.6 mm, 5 µm particles) column using an
acetonitrile-postassium phosphate buffer (0,1; pH 2.50) (225:775 v/v) mobile
phase. The column efluent was monitored at 208 nm for lincomycin. A calibration
curve, in the concentration range from 200 to 1800 µg ml-1 lincomycin, was
established. The HPLC method was applied for the determination of lincomycin in
pharmaceutical formulations, were satisfactory and ranged from 99.67% to
100.65% (R.S.D. ranged from 1.01% to 1.08%).
Key
words: HPLC determination, lincomycin, pharmaceutical formulations.
J. Serb. Chem. Soc. 62(12) 1227-1231 (1997)
UDC
615.777:547.673.6:543.242
JSCS-2497
Original
scientific paper
Kinetic determination
of Ti(III) in solution
RANKO M. SIMONOVIC, ALEKSANDAR R. IGOV* and RANGEL P. IGOV**
Faculty of Science, University of Pristina, YU-38000 Pristina,
*Ratko Pavlovic - NITEKS, Nis, YU-18000
Nis, and
Department of of Chemistry, Faculty of
Philosophy, University of Nis, YU-18000 Nis, Yugoslavia
(Received
6 March, revised 24 June 1997)
A new reaction is suggested and a new
kinetic method elaborated for the determination of Ti(III) traces in solution
of the basis of their catalyzing effect on 4-hydroxycoumarin oxidation By KMnO4 in acetate buffer. The
senisitivity of the method is 0.125 µg cm-3. The probable relative error of the method is below 7.0 % and
the method has relatively good selectivity.
Key
words: Ti(III) determination, kinetic determination
J. Serb. Chem. Soc. 62(12) 1233-1237 (1997)
UDC
615.777:547.673.6:543.242
JSCS-2498
Original
scientific paper
A kinetic method for the determination of the insecticide
endosulfan
GORDANA A. MILOVANOVIC and LJILJANA TRIFKOVIC
Faculty of Chemistry, University of Belgrade, P.O.Box 158,
YU-11001 Belgrade, Yugoslavia
(Received
10 April 1997)
A kinetic method for the determination of
the insecticide endosulfan
(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathpiepin,3-oxide)
is proposed. The activation effect of the insecticide on the oxidation of
carminic acid by hydrogen peroxide catalyzed by copper(II) has been used. The
reaction was carried out in an alkaline medium in a solution of acetone (0.17 mol
dm-3) and dimethylformamide (0.13 mol dm-3), thus enabling the
determination of endosulfan in the presence of the pesticides bifenox and
isoproturon. The method enables the determination of endosulfan in the
concentration range of 0.76-3.04 µg cm-3 with a relative standard deviation of 2.7%. The effect of other
pesticides on the accuracy of these determinations was investigated. In
addition, a kinetic expression for the proposed indicator reaction was
formulated, and the effect of temperature on the reaction rate was
investigated. The correlative activation parameters were also calculated.
Key
words: insecticide kinetic determination; endosulfan
6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-
2,4,3-benzodioxathiepin, 3-oxide), oxidation of carminic acid; hydrogen
peroxide.
J. Serb. Chem. Soc. 62(12) 1239-1243 (1997)
UDC
543.866:542.97:66,094.3:547.673.6
JSCS-2499
Note
NOTE
Substrate inhibition of yeast alcohol
dehydrogenase with comercial preparations of NAD+
S. TRIVIC, J. ZEREMSKI*, B. STANCIC**, and V.LESKOVAC***
Faculty of Science Novi Sad,
*Faculty of Technology and Metallurgy
Belgrade,
**Faculty of Agriculture Novi Sad, and
*** Faculty of Technology Novi Sad,
Yugoslavia
(Received
10 February, revised 24 June 1997)
A commercial preparation of NAD+ 95% from Sigma (Product
No. N 0632) afforded substrate inhibition in the yeast alcohol dehydrogenase
catalyzed oxidation of alcohols. A NAD+ 99% preparation from Sigma (Product No. N 1511) did not show
any substrate inhibition under similar experimental conditions. It was
concluded that the first preparation contained nucleotide impurities which
caused substrate inhibition by NAD+.
Key
words: yeast alcohol dehydrogenase, NAD+.
Subject index
1253
Author index
1157