J. Serb. Chem. Soc. 75 (10) 1315–1324 (2010)
UDC 547.863.11+544.478:544.354.3; JSCS–4054; doi: 10.2298/JSC091014109Z; Original scientific paper

Ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br): a green and neutral reaction media for the efficient, catalyst-free synthesis of quinoxaline derivatives
ABDOLKARIM ZARE, ALIREZA HASANINEJAD*, ABOLFATH PARHAMI, AHMAD REZA MOOSAVI-ZARE, FATEMEH KHEDRI, ZAHRA PARSAEE, MAASOOMEH ABDOLALIPOOR-SARETOLI, MAASOOMEH KHEDRI, MEHRNOOSH ROSHANKAR and HANAFIEH DEISI

Department of Chemistry, PayAMe Noor University (PNU) , Iran

*Department of Chemistry, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Iran

(Received 14 October 2009, revised 12 June 2010)

Quinoxaline derivatives were produced in excellent yields and short reaction times via the condensation of 1,2-diAMines with 1,2-diketones in the neutral ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) under catalyst-free and microwave irradiation conditions.

Keywords: quinoxaline; neutral ionic liquid; catalyst-free; 1,2-diAMine; 1,2-di¬ketone; green chemistry.

J. Serb. Chem. Soc. 75 (10) 1325–1335 (2010)
UDC 542.913+57–188:547.474.4; JSCS–4055; doi: 10.2298/JSC090410108X; Original scientific paper

Synthesis and bioactivity of erythro-nordihydroguaiaretic acid, threo-(–)-saururenin and their analogues

YAMU XIA, YUANYUAN ZHANG, WEI WANG, YINING DING and RUI HE*

College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, P. R. China

*College of Mathematics and Physics, Qingdao University of Science and Technology, Qingdao 266042, P. R. China

(Received 10 April, revised 11 June 2010)

Full details of the total syntheses of erythro-nordihydroguaiaretic acid, threo-(–)-saururenin and their analogues are presented. The syntheses were based on a unified synthetic strategy involving the Stobbe reaction, alkylation to construct the skeleton of lignans and resolution of the threo- and erythro-isomers. The syntheses were achieved in eight to nine steps from simple aromatic precursors, and by this route 13 lignans were obtained. Among the synthesized lignans, seven lignans were natural products; moreover three of the seven natural products were synthesized for the first time. The effect of 13 lignans was exAMined on HIV Tat transactivation in human epithelial cells, HSV-1 gene and human leukemic, liver, prostate, stomach and breast cancer cell. Bioactivity results indicated that one product showed activity against the HIV gene and five compounds exhibited anti-HSV activity.

Keywords: synthesis; bioactivity; NDGA; saururenin.

J. Serb. Chem. Soc. 75 (10) 1337–1346 (2010)
UDC 547.21:665.944.55:633.94; JSCS–4056; doi: 10.2298/JSC100322089N; Original scientific paper

n-Alkanes in the needle waxes of Pinus heldreichii var. pančići
BILJANA NIKOLIĆ, VELE TEŠEVIĆ*, IRIS ĐORĐEVIĆ**, MILKA JADRANIN***, MARINA TODOSIJEVIĆ***, SRĐAN BOJOVIĆ**** and PETAR D. MARIN*****

Institute of Forestry, Kneza Višeslava 3, 11000 Belgrade, Serbia

*Faculty of Chemistry, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia

**Faculty of Veterinary Medicine, University of Belgrade, Bulevar oslobođenja 18, 11000 Belgrade, Serbia

***Institute for Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia

****Institute for Biological Research “Siniša Stanković”, Bulevar despota Stefana 142, 11000 Belgrade, Serbia

*****Faculty of Biology, Institute of Botany and Botanical Garden “Jevremovac“, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia

(Received 22 March, revised 14 June 2010)

This is the first report of n-alkanes in needle epicuticular waxes of the variety Bosnian pine, Pinus heldreichii var. pančići. n-Hexane extracts of needle sAMples, originating from seven isolated localities in Serbia, were analysed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The results evidenced n-alkanes ranging from C18 to C33 in epicuticular waxes. The most abundant alkanes were C²⁷, C₂₃, C₂₅ and C₂₉ (12.53 %, 12.46 %, 12.00 % and 10.38 % on average, respectively). The carbon preference index (CPI_total) of Pinus heldreichii var. pančići ranged from 1.1 to 2.1 (1.6 on average), while the average chain length (ACL_total) ranged from 25.0 to 25.8 (25.3 on average). A high level of individual quantitative variation in all of these hydrocarbon parAMeters was also found. The obtained results were compared with the bibliographic references for Pinus heldreichii var. leucodermis and other species of the Pinus genus.

Keywords: Bosnian pine; Pinaceae; needles; n-alkanes.

J. Serb. Chem. Soc. 75 (10) 1347–1359 (2010)
UDC 582.623–035.27:547.384:547.431.4:615.28; JSCS–4057; doi: 10.2298/JSC100601117L; Original scientific paper

Chemical composition and screening of the antimicrobial and antioxidative activity of extracts of Stachys species
JELENA S. LAZAREVIĆ, RADOSAV M. PALIĆ*, NIKO S. RADULOVIĆ*, NOVICA R. RISTIĆ** and GORDANA S. STOJANOVIĆ*

Department of Pharmacy, Faculty of Medicine, University of Niš, Bul. Dr Zorana Đinđića 81, 18000 Niš, Serbia

*Department of Chemistry, Faculty of Science and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia

**Department of Chemistry, Faculty of Science and Mathematics, University of Priština, Kosovska Mitrovica, Serbia

(Received 3 June, revised 24 August 2010)

GC and GC/MS analyses of the diethyl ether and ethyl acetate extracts obtained from the aerial parts of Stachys germanica subsp. heldreichii (Boiss) Hayek, Stachys iva Griseb., Stachys plumosa Griseb. and Stachys scardica Griseb., Balkan peninsula endemics, were performed. One hundred and seventy-nine constituents, accounting for 88.8–98.1% of the total composition of the extracts, were identified. The common feature of the diethyl ether extracts was the high content of terpenoids and fatty acid-derived compounds, while the common feature of the ethyl acetate extracts was the prevalence of fatty acid-derived compounds. A disk diffusion method was used for the evaluation of the antimicrobial activities of the extracts against a panel of microorganisms (bacteria: Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enteritidis; fungi: Aspergillus niger and Candida albicans). The total antioxidant capacity of the extracts was evaluated by the phosphomolybdenum method. The preliminary bioassay results indicated that the diethyl ether extract of S. plumosa could be a possible source of antioxidant and antimicrobial compounds.

Keywords: Stachys; LAMiaceae; diethyl ether and ethyl acetate extracts; antimicrobial activity, antioxidant capacity.

J. Serb. Chem. Soc. 75 (10) 1361–1368 (2010)

J. Serb. Chem. Soc. 75 (10) 1369–1380 (2010)   

UDC 546.732’742’562’472’482.004.12:615.281/.282:66.097.8–914.7; JSCS–4059; doi: 10.2298/JSC100129110S; Original scientific paper

J. Serb. Chem. Soc. 75 (10) 1381–1389 (2010)

UDC 546.39+661.8’038+541.124:535–31; JSCS–4060; doi: 10.2298/JSC100219112S; Original scientific paper

J. Serb. Chem. Soc. 75 (10) 1391–1404 (2010)

UDC 547.538:532.14:532.74:541.4:615.214; JSCS–4061; doi: 10.2298/JSC100408116H; Original scientific paper

Artificial neural network prediction of the psychometric activities of phenylalkylAMines using DFT-calculated molecular descriptors

MINA HAGHDADI and MOHAMMAD H. FATEMI*

Department of Chemistry, IslAMic Azad University, Babol Branch, Iran

*Department of Chemistry, Mazandaran University, Babolsar, Iran

(Received 8 April, revised 11 May 2010)

In the present work, a quantitative structure–activity relationship (QSAR) method was used to predict the psychometric activity values (as mescaline unit, log MU) of 48 phenylalkylAMine derivatives from their density functional theory (DFT) calculated molecular descriptors and an artificial neural network (ANN). In the first step, the molecular descriptors were obtained by DFT calculation at the 6-311G^ level of theory. Then the stepwise multiple linear regression method was employed to screen the descriptor spaces. In the next step, an artificial neural network and multiple linear regressions (MLR) models were developed to construct nonlinear and linear QSAR models, respectively. The standard errors in the prediction of log MU by the MLR model were 0.398, 0.443 and 0.427 for training, internal and external test sets, respectively, while these values for the ANN model were 0.132, 0.197 and 0.202, respectively. The obtained results show the applicability of QSAR approaches by using ANN techniques in prediction of log MU of phenylalkylAMine derivatives from their DFT-calculated molecular descriptors.

Keywords: density functional theory; artificial neural network; multiple linear regression; quantitative structure–property relationship; phenylalkylAMines.

J. Serb. Chem. Soc. 75 (10) 1405–1412 (2010)

UDC 539.6+535.51:548.3; JSCS–4062, doi: 10.2298/JSC100320114D; Original scientific paper

The Wiener polarity index of molecular graphs of alkanes with a given number of methyl groups

HANYUAN DENG and HUI XIAO

College of Mathematics and Computer Science, Hunan Normal University, Changsha, Hunan 410081, P. R. China

(Received 20 March, revised 13 April 2010)

The Wiener polarity index of a graph G is the number of unordered pairs of vertices {u,v} of G such that the distance between u and v is equal to 3. In this paper, the maximum Wiener polarity index of molecular graphs of alkanes with a given number of methyl groups is studied.

Keywords: topological index; Wiener polarity index; distance; alkane with k methyl groups.

J. Serb. Chem. Soc. 75 (10) 1413–1420 (2010)

UDC 546.96–31+546.93–31+621.3.032.22–882:667.6:544.4; JSCS–4063; doi: 10.2298/JSC100310078P; Original scientific paper

Differences in the electrochemical behavior of ruthenium and iridium oxide in electrocatalytic coatings of activated titanium anodes prepared by the sol–gel procedure

VLADIMIR V. PANIĆ, ALEKSANDAR B. DEKANSKI, VESNA B. MIŠKOVIĆ—STANKOVIĆ*, SLOBODAN K. MILONJIĆ** and BRANISLAV Ž. NIKOLIĆ*

ICTM – Department of Electrochemistry, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia

*Faculty of Technology and Metallurgy, University of Belgrade, P. O. Box 350, 11001 Belgrade, Serbia

**Vinča Institute of Nuclear Science, P. O. Box 522, 11001 Belgrade, Serbia

(Received 10 March, revised 1 June 2010)

The electrochemical characteristics of Ti_0.6Ir_0.4O₂/Ti and Ti_0.6Ru_0.4O₂/Ti anodes prepared by the sol–gel procedure from the corresponding oxide sols, obtained by force hydrolysis of the corresponding metal chlorides, were compared. The voltAMmetric properties in H₂SO₄ solution indicate that Ti_0.6Ir_0.4O₂/Ti has more pronounced pseudocapacitive characteristics, caused by proton-assisted, solid state surface redox transitions of the oxide. At potentials negative to 0.0 V_SCE, this electrode is of poor conductivity and activity, while the voltAMmetric behavior of the Ti_0.6Ru_0.4O₂/Ti electrode is governed by proton injection/ejection into the oxide structure. The Ti_0.6Ir_0.4O₂/Ti electrode had a higher electrocatalytical activity for oxygen evolution, while the investigated anodes were of similar activity for chlorine evolution. The potential dependence of the impedance characteristics showed that the Ti_0.6Ru_0.4O₂/Ti electrode behaved like a capacitor over a wider potential range than the Ti_0.6Ir_0.4O₂/Ti electrode, with fully-developed pseudocapacitive properties at potentials positive to 0.60 VSCE. However, the impedance characteristics of the Ti_0.6Ir_0.4O₂/Ti electrode changed with increasing potential from resistor-like to capacitor-like behavior.

Keywords: activated titanium anodes; sol–gel procedure, ruthenium and iridium oxide; electrochemical impedance spectroscopy; pseudocapacitance.

J. Serb. Chem. Soc. 75 (10) 1421–1434 (2010)

UDC 542.97+544.6.076.32–033.5:665.7.035.7.000.57; JSCS–4064; doi: 10.2298/JSC100209111Z; Original scientific paper

Preparation and electrochemical application of rutin biosensor for differential pulse voltAMmetric determination of NADH in the presence of acetAMinophen

HAMID R. ZARE, REZA SAMIMI, NAVID NASIRIZADEH and MOHAMMAD MAZLOUM-ARDAKANI

Department of Chemistry, Yazd University, Yazd, 89195-741, Iran

(Received 9 February, revised 14 May 2010)

The electrocatalytic behavior of reduced nicotinAMide adenine di-nucleotide (NADH) was studied at the surface of a rutin biosensor, using various electrochemical methods. According to the results, the rutin biosensor had a strongly electrocatalytic effect on the oxidation of NADH with the overpotential being decreased by about 450 mV as compared to the process at a bare glassy carbon electrode, GCE. This value is significantly greater than the value of 220 mV that was reported for rutin embedded in a lipid-cast film. The kinetic parAMeters of the electron transfer coefficient, a, and the heterogeneous charge transfer rate constant, k_h, for the electrocatalytic oxidation of NADH at the rutin biosensor were estimated. Furthermore, the linear dynAMic range; sensitivity and limit of detection for NADH were evaluated using the differential pulse voltAMmetry method. The advantages of this biosensor for the determination of NADH are excellent catalytic activity and reproducibility, good detection limit and high exchange current density. The rutin biosensor could separate the oxidation peak potentials of NADH and acetAMinophen present in the sAMe solution while at a bare GCE, the peak potentials were indistinguishable.

Keywords: electrocatalytic behavior; rutin; NADH; biosensor, acetAMinophen.

J. Serb. Chem. Soc. 75 (10) 1435–1439 (2010)

UDC 539.12:66.094.1:544.6.004.12; JSCS–4065; doi: 10.2298/JSC100520081O; Extended abstract

EXTENDED ABSTRACT

The electrochemical properties of carbon nanotubes and carbon XC-72R and their application as Pt supports

MAJA D. OBRADOVIĆ

Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia

(Received 20 May 2010)

The results of an investigation of two sAMples of commercial multi-walled carbon nanotubes and a sAMple of carbon black, in the raw and activated state, were presented in the lecture. The activation of the carbon materials led to the formation of an abundance of oxygen-containing functional groups on the surface, an increased electrochemically active surface area, an enhanced charge storage ability and a promotion of the electron-transfer kinetics. It was presented that the morphology of the carbon nanotubes is important for the electrochemical properties, because nanotubes with a higher proportion of edge and defect sites showed faster electron transfer and pseudocapacitive redox kinetics. Modification of oxidized nanotubes by ethylenediAMine and wrapping by poly(diallyldimethylAMmonium chloride) led to a decrease in the electrochemically active surface area and to reduced electron-transfer kinetics. Pt nanoparticles prepared by the microwave-assisted polyol method were deposited at the investigated carbon materials. A much higher efficiency of Pt deposition was observed on the modified CNTs than on the activated CNTs. The activity of the synthesized catalyst toward electrochemical oxygen reduction was almost the sAMe as the activity of the commercial Pt/XC-72 catalyst.

Keywords: carbon nanotubes; morphology; electrochemical properties; Pt nanoparticles; electrocatalyst for oxygen reduction.

J. Serb. Chem. Soc. 75 (10) 1441–1452 (2010)

UDC Methylprednisolone:615.451.1:615.015.1:543.612; JSCS–4066; doi: 10.2298/JSC100115087S; Original scientific paper

Methylprednisolone and its related substances in freeze-dried powders for injections

LJILJANA SOLOMUN, SVETLANA IBRIĆ*, VLATKA VAJS**, IVAN VUČKOVIĆ** and ZORICA VUJIĆ*

Hemofarm, A.D. Vršac, Serbia

*Faculty of Pharmacy, Belgrade, Serbia

**Faculty of Chemistry, Belgrade, Serbia

(Received 15 January, revised 24 May 2010)

In this work, the behavior of the active pharmaceutical substances methylprednisolone (in a form of methylprednisolone sodium succinate) in finished pharmaceutical dosage form, i.e., freeze-dried powder for injections was exAMined. The goal was to evaluate the chemical stabilities of methyl-prednisolone sodium succinate packaged in a dual chAMber vial, as a specific container closure system. The effect of different parAMeters: temperature, moisture and light were monitored. The method proposed by United States Pharmacopeia was used to determine concentrations of methylprednisolone, as the sum of the concentration of methylpredisolone esters (17-hydrogen succinate and 21-hydrogen succinate) and free methylprednisolone. The HPLC method was used for stability evaluation of the active substance and determination of related substances. Four main degradation products were registered. Temperature has a major impact on the degradation process with the appearance of 3 degradation products (impurities B, C and D), while the presence of light caused an increasing content of impurity A. Identification of impurity B, C and D has been realized using mass and NMR spectroscopy. All three substances are substances related to methylprednisolone.

Keywords: methylprednisolone sodium succinate; freeze-dried powder; container closure system; stability; impurities.

J. Serb. Chem. Soc. 75 (10) 1453–1461 (2010)

UDC 582.795–035.27:546.19+546.881+546.48:66–914(497.11); JSCS–4067; doi: 10.2298/JSC100319079S; Original scientific paper

Urban deciduous tree leaves as biomonitors of trace element (As, V and Cd) atmospheric pollution in Belgrade, Serbia

KATARINA M. ŠUĆUR, MIRA P. ANIČIĆ*, MILICA N. TOMAŠEVIĆ*, DAVOR Z. ANTANASIJEVIĆ**, ALEKSANDRA A. PERIĆ-GRUJIĆ** and MIRJANA DJ. RISTIĆ**

National Library of Serbia, Skerlićeva 1, 11000 Belgrade, Serbia

*Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Zemun, Serbia

**Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade, Serbia

(Received 19 March, revised 18 May 2010)

Leaves of common deciduous trees: horse chestnut (Aesculus hippocastanum) and linden (Tilia spp.) from three parks within the urban area of Belgrade were studied as biomonitors of trace element (As, V, and Cd) atmospheric pollution. The May–September trace element accumulation in the leaves, and their temporal trends, were assayed in a multi-year period (2002–2006). Significant accumulation in the leaves was evident for As and V, but not so regularly for Cd. Slightly decreasing temporal trends of V and As ac-cumulated in the leaf tissues were observed over the years. During the time span, the concentrations of Cd remained approximately on the sAMe level, except in May 2002 and September 2005, when a rapid increase was observed. The May–September accumulations of As and V were higher in horse chestnut than in linden, although both may be used as biomonitors for these elements, and optionally for Cd in conditions of its high atmospheric loadings.

Keywords: trace elements; tree leaves; biomonitoring; Aesculus hippocastanum; Tilia spp.; ICP-MS.

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