J. Serb. Chem. Soc. 75 (8) 1019–1032 (2010)
UDC 667.021+547.821:66.081.2.004.12:54–145.55:541.621; JSCS–4027; doi: 10.2298/JSC091009074A; Original scientific paper

Synthesis, structure and solvatochromic properties of 3-cyano-4,6-diphenyl-5-(3- and 4-substituted phenylazo)-2-pyridones
ADEL S. ALIMMARI, ALEKSANDAR D. MARINKOVIĆ, DUŠAN Ž. MIJIN, NATAŠA V. VALENTIĆ, NINA TODOROVIĆ* and GORDANA S. UŠĆUMLIĆ

Department of Organic Chemistry, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, P.O. Box 3503, 11120 Belgrade, Serbia

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

(Received 9 October 2009, revised 10 May 2010)

A series of some new pyridone arylazo dyes was synthesized from the corresponding diazonium salts and 3-cyano-4,6-diphenyl-2-pyridone using the classical reaction for the synthesis of the azo compounds. The structures of these dyes were confirmed by UV–Vis, FT-IR and ¹H-NMR spectroscopic techniques. The solvatochromism of the dyes was evaluated with respect to visible absorption properties in various solvents. The effects of solvent dipolarity/polarizability and solvent/solute hydrogen bonding interactions were analyzed by means of the linear solvation energy relationship concept proposed by KAMlet and Taft. The 2-pyridone/2-hydroxypiridine tautomeric equilibration was found to depend on the substituents as well as on the solvents.

Keywords: arylazo pyridone dyes; absorption spectra; solvent effect; substituent effect; tautomeric equilibration.

J. Serb. Chem. Soc. 75 (8) 1033–1040 (2010)
UDC 547.853’593+547.854:547.571:28 615.28–188; JSCS–4028; doi: 10.2298/JSC090106060D; Short communication

SHORT COMMUNICATION

Synthesis of Biginelli products of thiobarbituric acids and their antimicrobial activity

VIJAY V. DABHOLKAR and TRIPATHI DILIP RAVI

Organic Research Laboratory, Department of Chemistry, Mumbai University, K. C. College, Churchgate, Mumbai-400 020, India

(Received 6 January 2009, revised 26 April 2010)

A simple and efficient method has been developed for the synthesis of 2,4,7-tri(substituted)phenyl-2,4,8,10-tetraza-3,9-dithioxo-5-oxobicyclo[4.4.0]dec-1(6)-ene (4) and 2,4,7-tri(substituted)phenyl-2,4,8,10-tetraza-3-thioxo-5,9-dioxobicyclo[4.4.0]dec-1(6)-ene (5), by a one-pot, three-component cyclocondensation reaction of a 1,3 dicarbonyl compound (thiobarbituric acid), an aromatic aldehyde, and urea/thiourea using catalytic a AMount of concentrated HCl in refluxing ethanol. Representative sAMples were screened for their anti-microbial activity against the GrAM-negative bacteria, Escherichia coli and Proteus aeruginosa, and the GrAM-positive bacteria, Staphyllococcus aureus and Corynebacterium diphtheriae using the disc diffusion method. The structures of the products were confirmed by IR, ¹H- and ¹³C-NMR spectroscopy, as well as by elemental analysis.

Keywords: aromatic aldehydes; dihydropyrimidine; thiobarbituric acid.

J. Serb. Chem. Soc. 75 (8) 1041–1052 (2010)
UDC *Pseudomonas aeruginosa+54.05:577.112+612.398; JSCS–4029; doi: 10.2298/JSC100125088I; Original scientific paper

Isolation and partial characterization of protease from Pseudomonas aeruginosa ATCC 27853
LIDIJA IZRAEL-ŽIVKOVIĆ, GORDANA GOJGIĆ-CVIJOVIĆ* and IVANKA KARADŽIĆ

School of Medicine, Department of Chemistry, University of Belgrade, Višegradska 26, 11000 Belgrade, Serbia

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

Received 25 January, revised 26 April 2010)

Enzymatic characteristics of a protease from a medically important, referent strain of Pseudomonas aeruginosa ATCC 27853 were determined. According to sodium dodecyl sulfate polyacrylAMide gel electrophoresis, SDS-PAGE, and gel filtration, it was estimated that the molecular mass of the purified enzyme was about 15 kDa. Other enzymatic properties were found to be: pH optimum 7.1, pH stability between 6.5 and 10; temperature optimum around 60 °C while the enzyme was stable at 60 °C for 30 min. Inhibition of the enzyme was observed with metal chelators, such as EDTA and 1,10-phenanthroline, suggesting that the protease is a metalloenzyme. Furthermore, the enzyme contains one mole of zinc ion per mole of enzyme. The protease was stable in the presence of different organic solvents, which enables its potential use for the synthesis of peptides.

Keywords: protease; Pseudomonas aeruginosa; purification; characterization.

J. Serb. Chem. Soc. 75 (8) 1053–1061 (2010)
UDC 547.963.32+547.455.5+57.088:612.12:575.113; JSCS–4030; doi: 10.2298/JSC091223084J; Original scientific paper

Comparison of phenol-based and alternative RNA isolation methods for gene expression analyses
KSENIJA V. JAKOVLJEVIĆ, MILENA R. SPASIĆ, EMINA J. MALIŠIĆ, JELENA D. DOBRIČIĆ, ANA M. KRIVOKUĆA and RADMILA N. JANKOVIĆ

Department of Experimental Oncology, Institute of Oncology and Radiology of Serbia, Pasterova 14, 11000 Belgrade

(Received 23 December 2009, revised 5 February 2010)

The widespread use of gene expression analyses has been limited by the lack of critical evaluations of the methods used to extract nucleic acids from human tissues. For evaluating gene expression patterns in whole blood or leukocytes, the method of RNA isolation needs to be considered as a critical variable in the design of the experiments. Quantitative real-time PCR (qPCR) is widely used for the quantification of gene expression in today’s clinical practice. Blood sAMples as a preferred RNA source for qPCR should be carefully handled and prepared in order not to inhibit gene expression analyses. The present study was designed to compare the frequently employed guanidine thiocyanate–phenol–chloroform-based method (TRI Reagent^®) with two alternative RNA isolation methods (6100 PrepStation and QIAAMp^®) from whole blood or leukocytes for the purpose of gene expression analysis in chronic myeloid leukemia (CML) patients. Based on the results of this study, for the best combination of yield and RNA extraction purity, taking into account the necessary AMount of the clinical sAMple and performance time, the protocol using phenol-based TRI Reagent^® for RNA extraction from leukocytes is suggested as the most suitable protocol for this specific gene expression analysis.

Keywords: RNA isolation; blood; leukocytes; TRI Reagent^®; PCR.

J. Serb. Chem. Soc. 75 (8) 1063–1074 (2010)

J. Serb. Chem. Soc. 75 (8) 1075–1084 (2010)

UDC 542.9+547.571+547.551+547.442.2+546.732’742’472:615.281–188; JSCS–4032; doi: 10.2298/JSC091026098I; Original scientific paper

J. Serb. Chem. Soc. 75 (8) 1085–1092 (2010)

UDC 547.496.2+547.821:546.562’472:548.7:54–77; JSCS–4033; doi: 10.2298/JSC091019097M; Original scientific paper

J. Serb. Chem. Soc. 75 (8) 1093–1098 (2010)

UDC 547.53:547.686:54.02; JSCS–4034; doi: 10.2298/JSC091207077V; Original scientific paper

On the number of Kekulé structures of fluoranthene congeners

DAMIR VUKIČEVIĆ, JELENA ĐURĐEVIĆ* and IVAN GUTMAN*

Faculty of Natural Sciences and Mathematics, University of Split, Nikole Tesle 12, HR-21000 Split, Croatia

*Faculty of Science, University of Kragujevac, P. O. Box 60, 34000 Kragujevac, Serbia

(Received 7 December 2009)

The Kekulé structure count K of fluoranthene congeners is studied. It is shown that for such polycyclic conjugated π-electron systems, either K = 0 or K ≥ 3. Moreover, for every t ≥ 3, there are infinitely many fluoranthene congeners having exactly t Kekulé structures. Three classes of Kekuléan fluoranthenes are distinguished: i) Φ₀ – fluoranthene congeners in which neither the male nor the female benzenoid fragment has Kekulé structures, ii) Φ_m – fluoranthene congeners in which the male benzenoid fragment has Kekulé structures, but the female does not, and iii) Φ_fm – fluoranthene congeners in which both the male and female benzenoid fragments have Kekulé structures. Necessary and sufficient conditions are established for each class, Φ = Φ₀, Φ_m, Φ_fm, such that for a given positive integer t, there exist fluoranthene congeners in Φ with the property K = t.

Keywords: fluoranthenes; Kekulé structure; polycyclic aromatic hydrocarbons.

J. Serb. Chem. Soc. 75 (8) 1099–1113 (2010)

UDC 546.681.3:622.349.2:66.061.247:543; JSCS–4035, doi: 10.2298/JSC090630072M; Original scientific paper

Liquid–liquid extraction and recovery of gallium(III) from acid media with 2-octylAMinopyridine in chloroform: analysis of bauxite ore

SANDIP V. MAHAMUNI, PRAKASH P. WADGAONKAR* and MANSING A. ANUSE

Analytical Chemistry Laboratory, Department of Chemistry, Shivaji University, Kolhapur – 416 004, India

*Polymer Science and Engineering Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune – 411 008, India

(Received 30 June 2009, revised 26 April 2010)

The liquid–liquid extraction of gallium(III) from hydrochloric acid solution using 2-octylAMinopyridine (2-OAP) in chloroform was investigated. The extraction of gallium(III) from 6.0–9.0 mol dm^-3 hydrochloric acid was found to be quantitative using 0.033 mol dm^-3 2-OAP in chloroform. The effect of the reagent concentration and other parAMeters on the extraction of gallium(III) was also studied. The stoichiometry of the extracted species of gallium(III) was determined based on the slope analysis method. The extraction reaction proceeded via the anion exchange mechanism from hydrochloric acid and the extracted species was [RR’NH₂⁺GaCl₄^-]org. The extraction of gallium(III) was performed in the presence of various ions to ascertain the tolerance limit to individual ions. The temperature dependence of the extraction equilibrium constants was exAMined to estimate the apparent thermodynAMic functions (∆H, ∆S and ∆G) for the extraction reaction. Gallium(III) was successfully separated from commonly associated metal ions, such as Zn(II), Pb(II), Cd(II), Hg(II), Bi(III), Al(III), Se(IV), Sb(III), Sn(IV), In(III), Tl(I) and Tl(III). However, gallium(III) was separated from Fe(III) from weak organic acid media. The procedure was also extended to the determination of gallium(III) in bauxite ore by the standard addition method.

Keywords: liquid–liquid extraction; gallium(III); 2-OAP; recovery of gallium from bauxite.

J. Serb. Chem. Soc. 75 (8) 1115–1124 (2010)

UDC 547.214+546.881’77–31+544.478:66.094.258.094.3; JSCS–4036; doi: 10.2298/JSC091204099M; Original scientific paper

Oxidative dehydrogenation of isobutane over supported V–Mo mixed oxides

GHEORGHIŢA MITRAN, IOAN-CEZAR MARCU, ADRIANA URDĂ and IOAN SĂNDULESCU

Department of Technological Chemistry and Catalysis, Faculty of Chemistry, University of Bucharest, 4-12, Blv. Regina Elisabeta, 030018, Bucharest, Romania

(Received 4 December 2009)

Vanadium–molybdenum oxides supported on Al₂O₃, CeO₂ and TiO₂ were prepared by a “wet” impregnation method, characterized using XRD, N₂ adsorption, UV–Vis spectroscopy, electrical conductivity measurements and tested in the oxidative dehydrogenation of isobutane. The catalytic performance in the oxidative dehydrogenation of isobutane at 400–550 °C depended on the nature of support and on the content of VMoO species on the support. The catalysts supported on alumina were more active and selective than those supported on ceria and titania.

Keywords: vanadia–molybdena catalysts; isobutene; oxidative dehydrogenation.

J. Serb. Chem. Soc. 75 (8) 1125–1148 (2010)

UDC 504.45+502.37(282.243.7)(497.11); JSCS–4037; doi: 10.2298/JSC091102075Z; Original scientific paper

Long-term changes in the eco-chemical status of the Danube River in the region of Serbia

IVAN ŽIVADINOVIĆ, KONSTANTIN ILIJEVIĆ*, IVAN GRŽETIĆ* and ALEKSANDAR POPOVIĆ*

Srbijavode, Bulevar umetnosti 2, 11070 Belgrade, Serbia

*Faculty of Chemistry, University of Belgrade, Studentski trg 12–16, 11000 Belgrade, Serbia

(Received 2 November, revised 8 December 2009)

The Danube River is an international river, one part of which flows through Serbia. The eco-chemical status of the Danube River is a constant topic of interest both at the local level, in each country through which the Danube flows, and at the international level. General interest to ensure the sustainable and equitable use of waters and freshwater resources in the Danube River Basin led to the development of a system for monitoring the river, which has produced data sets of its eco-chemical status. These have been collected over many years in Serbia; however, the present interest was focused only on the period from 1992 until 2006, i.e., a 15-year period. The process of defining trends of selected eco-chemical parAMeters, using linear regression analysis with a defined level of significance, and their separation from natural variability is of the highest importance for defining the changes in the water parAMeters. Through them, the fate and behavior of the eco-chemical parAMeters of the Danube in Serbia can be recognized and the prediction of their trends in the near future can be attempted. The obtained results revealed a constant improvement and acceptable trends of the eco-chemical status of the Danube River, as well as, substantial differences in the quality of the inflowing and out flowing water.

Keywords: Danube River; long-term spatial and temporal trends; self-puri-fication; linear regression.

J. Serb. Chem. Soc. 75 (8) 1149–1159 (2010)

*CYP1A+*MT:504.054(26):597; JSCS–4038; doi: 10.2298/JSC091204099M; Original scientific paper

CYP1A and metallothionein expression in the hepatopancreas of Merluccius merluccius and Mullus barbatus from the Adriatic Sea

MIRJANA MIHAILOVIĆ, MIODRAG PETROVIĆ, NEVENA GRDOVIĆ, SVETLANA DINIĆ, ALEKSANDRA USKOKOVIĆ, MELITA VIDAKOVIĆ, ILIJANA GRIGOROV, DESANKA BOGOJEVIĆ, SVETLANA IVANOVIĆ-MATIĆ, VESNA MARTINOVIĆ, JELENA ARAMBAŠIĆ, DANIJELA JOKSIMOVIĆ*, SVETLANA LABUS-BLAGOJEVIĆ** and GORAN POZNANOVIĆ

Institute for Biological Research “Siniša Stanković”, University of Belgrade, Belgrade, Serbia

*Institite of Marine Biology, Kotor, Montenegro

**Milan Jovanović-Batut Institute for Public Health, Belgrade, Serbia

(Received 29 October, revised 11 December 2009)

The enzyme CYP1A is an established biomarker of fish exposure to polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). The metallothioneins (MT), a fAMily of Cys-rich proteins, bind a wide range of metals and participate in their metabolism. The aim of the study was to exAMine the correlation between CYP1A and MT expression in commercially important fish species Mullus barbatus and Merluccius merluccius and contAMinants (PAHs, PCBs, toxic metals) in seawater and sediment from three localities with different level of contAMination in the Adriatic Sea in winter, i.e., PlatAMuni, Valdanos and the port of Bar. The relative concentration of CYP1A was the highest in both fish species from Bar. Increased concentrations of PCBs in the seawater were observed only in Bar. A species-specific higher increase in the protein concentration of CYP1A was observed in Mullus barbatus compared to Merluccius merluccius. The levels of MT were the highest in Merluccius merluccius from Bar and in Mullus barbatus from Valdanos. The induction of MT correlated with the elevated concentrations of Cu and Pb determined by chemical analysis of the seawater from Bar and Valdanos, respectively. According to the chemical analysis of the seawater and the biological response of the fish, the PlatAMuni locality exhibited the lowest level of contAMination.

Keywords: CYP1A; metallothionein; polycyclic aromatic hydrocarbons; polychlorinated biphenyls; metals; fish.

J. Serb. Chem. Soc. 75 (8) 1161–1165 (2010)

UDC 541.121+536.247+544.35:504.75; JSCS–4039; doi: 10.2298/JSC100223100V; Extended abstract

EXTENDED ABSTRACT

Liquid–liquid equilibria in solutions with potential ecological importance

ZORAN P. VIŠAK

Centro Química Estrutural, Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001, Lisboa, Portugal

(Received 23 February, revised 18 March 2010)

In the last three years, our research follows two main issues, defined by the slogans: “green meets toxic” and “green meets green”. The first issue considers the potential use of AMbient friendly solvents for toxic organic compounds of industrial and practical importance. The other is related to liquid phase behavior in solutions of ecologically sustainable substances. The “green” solvents studied are: ionic liquids, liquid poly(ethylene glycol), glycerol and 1,2- and 1,3-propanediol.

Keywords: sustainable solvents; phase equilibria, poly(ethylene glycol); glycerol; propanediols; ionic liquids.

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