J. Serb. Chem. Soc. 74 (11) 1155–1193 (2009)
UDC 615.285+541.459:616.936; JSCS–3909; doi: 10.2298/JSC0911155О; Review

Review

Antimalarial peroxides
DEJAN M. OPSENICA and BOGDAN A. ŠOLAJA*

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

*Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 51, 11158 Belgrade, Serbia

(Received 19 May 2009)

The problem of endemic malaria continues unabated globally. Malaria affects 40 % of the global population, causing an estimated annual mortality of 1.5–2.7 million people. The World Health Organization (WHO) estimates that 90 % of these deaths occur in sub-Saharan Africa AMong infants under the age of five. While a vaccine against malaria continues to be elusive, chemotherapy remains the most viable alternative towards treatment of the disease. During last years, the situation has become urgent in many ways, but mainly because of the development of chloroquine-resistant (CQR) strains of Plasmodium falciparum (Pf). The discovery that artemisinin (ART, 1), an active principle of Artemisia annua L., expresses a significant antimalarial activity, especially against CQR strains, opened new approaches for combating malaria. Since the early 1980s, hundreds of semisynthetic and synthetic peroxides have been developed and tested for their antimalarial activity, the results of which were extensively reviewed. In addition, in therapeutic practice, there is no reported case of drug resistance to these antimalarial peroxides. This review summarizes recent achievements in the area of peroxide drug development for malaria chemotherapy.

Keywords: antimalarial; peroxides; trioxanes; trioxolanes; tetraoxanes; chimeras.

J. Serb. Chem. Soc. 74 (11) 1195–1205 (2009)
UDC 547.783+542.913+54.02:532.74; JSCS–3910; doi: 10.2298/JSC0911195D; Original scientific paper

Synthesis, structure and solvatochromism of 5-methyl-5-(3- or 4-substituted phenyl)hydantoins
NATALIJA D. DIVJAK, NEBOJŠA R. BANJAC, NATAŠA V. VALENTIĆ and GORDANA S. UŠĆUMLIĆ
Department of Organic Chemistry, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, P.O. Box 3505, 11120 Belgrade, Serbia

(Received 1 July 2008, revised 8 July 2009)

Several 5-methyl-5-(3- or 4-substituted phenyl)hydantoins were prepared and their ultraviolet absorption spectra were recorded in the region 200–400 nm in twelve solvents of different polarity. The effect of solvent dipo¬larity/polarizability and solvent/solute hydrogen bonding interactions were analyzed by means of the linear solvation energy relationship (LSER) concept proposed by KAMlet and Taft. The lipophilic activity of the investigated hydantoins was estimated by calculation of log P values with Advanced Chemistry Development Software. The calculated values of log P were correlated with the contribution of hydrogen bond donor–solvent interactions. By employing the thus obtained linear dependence, the pharmacological activity of the studied hydantoin derivatives is discussed.

Keywords: hydantoins; absorption frequencies; LSER; lipophilicity parAMeter; specific solvent, interactions; pharmacological activity.

J. Serb. Chem. Soc. 74 (11) 1207–1218 (2009)
UDC 544.182.342:544.147:544.144.2; JSCS–3911; doi: 10.2298/JSC0911207M; Original scientific paper

Structural requirements for ligands of the δ-opioid receptor
VUK I. MIĆOVIĆ, MILOVAN D. IVANOVIĆ*^,** and LJILJANA DOŠEN-MIĆOVIĆ*^,**
Institute for General and Physical Chemistry, Belgrade, Serbia

*Faculty of Chemistry, University of Belgrade, Studentski trg 12–16, 11158 Belgrade, Serbia

**ICTM, Center for Chemistry, University of Belgrade, Njegoševa 12, Belgrade, Serbia

(Received 22 October 2008, revised 28 May 2009)

The δ-opioid receptor is sensitive to ligand geometry. In order to assist the synthesis of new δ-selective opioid ligands, the structure elements of δ-selective opioid ligands necessary for their effective binding were investigated. The automated docking procedure with a flexible ligand was used to simulate the binding of 17 δ-selective ligands to the δ-receptor. It was found that voluminous N-alkyl groups reduce the binding potency of naltrindole derivatives by preventing the ligands from adopting the preferred conformation in the receptor. This was confirmed by enantiospecific binding of chiral compounds where only one enantiomer adopts the naltrindole-like preferred conformation in the binding pocket. Voluminous groups replacing the hydroxyl group in the 3-hydroxybenzyl fragment of naltrindole analogs reduce the binding potency due to unfavorable steric interactions with the receptor. The two diastereoisomers of the potent δ-opioid ligand SNC80 confirmed the preferred binding conformation and the major receptor–ligand interactions.

Keywords: molecular modeling; δ-opioid receptor; ligand–receptor interactions; docking simulation.

J. Serb. Chem. Soc. 74 (11) 1219–1228 (2009)

UDC 547.78+547.772+542.913+54-41:615.281-188; JSCS–3912; doi: 10.2298/JSC0911217D; Short communication

Short communication

Synthesis and characterization of selected fused isoxazole and pyrazole derivatives and their antimicrobial activity
VIJAY V. DABHOLKAR and FAISAL Y. ANSARI

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

(Received 4 July 2008, revised 28 May 2009)

New potent antibacterials, fused isoxazole and pyrazole derivatives, were synthesized using 5,5-dimethylcyclohexane-1,3-dione (1) and 3-[(4-chlorobenzylidene)AMino]-2-thioxoimidazolidin-4-one (2) as synthons. Aromatic aldehydes on condensation with 1 and 2 gave 2-arylidene-5,5-dimethylcyclohexane-1,3-dione (3) and 5-arylidene-3-[(4-chlorobenzylidene)AMino]-2-thioxoimidazolidin-4-one (4), respectively. Compounds 3 and 4 were forced to undergo heterocyclization reaction with nucleophilic reagents to give the title compounds. The newly synthesized heterocyles (5–8) were characterized based on their chemical properties and spectroscopic data, and were found to inhibit Staphylococcus aureus and Corynebacterium diphtheriae.

Keywords: isoxazole; pyrazole; thiohydantoin; dimedone; antibacterial activity.

J. Serb. Chem. Soc. 74 (11) 1229–1240 (2009)
UDC 58.056:634.84:581.45; JSCS–3913; doi: 10.2298/JSC0911229B; Original scientific paper

J. Serb. Chem. Soc. 74 (11) 1241–1248 (2009)

J. Serb. Chem. Soc. 74 (11) 1249–1258 (2009)

UDC 546.982-386+547.171’26:542.913; JSCS–3915; doi: 10.2298/JSC0911249Z; Original scientific paper

J. Serb. Chem. Soc. 74 (11) 1259–1271 (2009)

UDC 546.472’492.004.12:548.7:547.772:543.57; JSCS–3916, doi: 10.2298/JSC0911259J; Original scientific paper

Transition metal complexes with pyrazole-based ligands.

Part 29. Reactions of zinc(II) and mercury(II) thiocyanate with 4-acetyl-3-AMino-5-methylpyrazole

ŽELJKO K. JAĆIMOVIĆ, GORAN A. BOGDANOVIĆ*, BERTA HOLLÓ**, VUKADIN M. LEOVAC** and KATALIN MÉSZÁROS SZÉCSÉNYI**

Faculty of Metallurgy and Technology, Podgorica, Montenegro, Serbia

*”Vinča” Institute of Nuclear Sciences, Laboratory of Theoretical Physics and Condensed Matter Physics, Belgrade, Serbia

**Faculty of Sciences, Department of Chemistry, Novi Sad, Serbia

(Received 2 June, revised 4 October 2009)

The work is concerned with the crystal and molecular structures of zinc(II) and mercury(II) complexes with 4-acetyl-3-AMino-5-methyl-pyrazole (aAMp) of the coordination formulae [Zn(NCS)₂(aAMp)₂] and (HaAMp)₂[Hg(SCN)₄]. The zinc(II) complex was obtained by the reaction of a warm methanolic solution of aAMp with a mixture of zinc(II) nitrate and AMmonium thiocyanate, whereas the mercury(II) complex was prepared by the reaction of a warm ethanolic solution of aAMp and a warm, slightly acidified aqueous solution of [Hg(SCN)₄]^2-. Both complexes have a tetrahedral geometry, which in the case of zinc complex is formed by monodentate coordination of two aAMp molecules and two isothiocyanate groups. The Zn(II) and Hg(II) atoms have significantly deformed coordination geometry. In both crystal structures the pyrazole derivative has a planar form, probably stabilized by an intrAMolecular N–H···O hydrogen bond. Apart from the X-ray structural analysis, the isolated complexes were characterized by elemental analysis, IR spectroscopy, conductometric measurements and thermal analysis.

Keywords: zinc(II) complex; mercury(II) complex; 4-acetyl-3-AMino-5-methyl¬pyrazole; crystal structure; thermal analysis.

J. Serb. Chem. Soc. 74 (11) 1273–1282 (2009)

UDC 547.652-304.4:546.562’742’472:543.635.6; JSCS–3917; doi: 10.2298/JSC0911273K; Original scientific paper

1-Naphthylazo derivatives of some 1,3-dicarbonyl compounds and their Cu(II), Ni(II) and Zn(II) complexes

K. KRISHNANKUTTY, MUHAMMED BASHEER UMMATHUR* and PERUMPALLI UMMER

Department of Chemistry, University of Calicut, Kerala-673635, India

*Department of Chemistry, Unity Women’s College, Manjeri, Kerala-676122, India

(Received 16 March, revised 12 July 2009)

The coupling of diazotized 1-AMinonaphthalene with 1,3-dicarbonyl compounds (acetylacetone, methylacetoacetate and acetoacetanilide) yielded a new series of bidentate ligand systems (HL). Analytical, IR, ¹H-NMR and mass spectral data indicate that the compounds exist in the intrAMolecularly hydrogen bonded keto-hydrazone form. With Ni(II), Cu(II) and Zn(II), these potential monobasic bidentate ligands formed [ML₂] type complexes. The IR, ¹H-NMR and mass spectral data of the complexes are consistent with the replacement of the chelated hydrazone proton of the ligand by a metal ion, thus leading to a stable six-membered chelate ring involving the hydrazone nitrogen and the hydrogen bonded carbonyl oxygen. The Ni(II) and Zn(II) chelates are diAMagnetic, while the Cu(II) complexes are parAMagnetic. In the metal complexes of the naphthylazo derivatives of acetylacetone and methylacetoacetate, the acetyl carbonyl is involved in coordination, whereas in the chelates of the naphthylazo derivative of acetoacetanilide, the anilide carbonyl is bonded with the metal ion.

Keywords: naphthylhydrazones; Cu(II), Ni(II) and Zn(II) complexes; IR, mass and NMR spectra.

J. Serb. Chem. Soc. 74 (11) 1283–1292 (2009)

UDC *T-2 toxin:66.021.3+549–032.61; JSCS–3918; doi: 10.2298/JSC0911283D; Original scientific paper

T-2 toxin adsorption by hectorite

ALEKSANDRA DAKOVIĆ, ŽIVKO SEKULIĆ, GEORGE E. ROTTINGHAUS*, ANA STOJANOVIĆ, SONJA MILIĆEVIĆ and MILAN KRAGOVIĆ

Institute for Technology of Nuclear and Other Mineral Raw Materials, P.O. Box 390, 11000 Belgrade, Serbia

*Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA

(Received 4 February 2009)

The adsorption of T-2 toxin by the natural smectite mineral – hectorite at pH 3.0, 7.0 and 9.0 was investigated. The results of T-2 toxin adsorption on hectorite showed that the T-2 adsorption capacity decreased with increasing concentration of adsorbent in the suspension for all the investigated pH values. From the adsorption isotherms, an increase in T-2 toxin adsorption with increasing initial T-2 toxin concentration was observed for all the investigated pH values. The T-2 toxin adsorption by hectorite followed a non-linear (Langmuir) type of isotherm at pH 3.0, 7.0 and 9.0, with correlation coefficients (r²) of 0.943 at pH 3.0, 0.919 at pH 7.0 and 0.939 at pH 9.0. The estimated maximum T-2 toxin adsorption by hectorite based on the Langmuir fit to the data (9.178 mg/g at pH 3.0, 9.930 mg/g at pH 7.0, and 19.341 mg/g at pH 9.0), indicated that the adsorption of T-2 toxin by hectorite is pH dependent. The obtained data suggest the existence of specific active sites in hectorite onto which the T-2 toxin is adsorbed.

Keywords: smectite; hectorite; mycotoxins; T-2 toxin; adsorption.

J. Serb. Chem. Soc. 74 (11) 1293–1302 (2009)

UDC 669.112.227+669.14.018.8:620.193; JSCS–3919 doi: 10.2298/JSC0911293Y; Original scientific paper

Effect of solution treatment conditions on the sensitization of austenitic stainless steel

XIAOFEI YU*, SHENHAO CHEN*,** and LIANG WANG*

*Department of Chemistry, Shandong University, Jinan 250100, PR China

**State Key Laboratory for Corrosion and Protection, Shenyang 110016, PR China

(Received 5 February, revised 27 May 2009)

In this study, the impact of the conditions of solution treatment on the degree of sensitization (DOS) of austenitic stainless steel (AISI 304) was investigated in detail. The results derived from the electrochemical potentiodynAMic reactivation (EPR) test indicated that the DOS decreased as the solution treatment temperature and time increased. The reason for this was studied via the SEM morphologies and EDS results, which indicated that the grain size influenced the DOS. Furthermore, cellular automaton (CA) was utilized to simulate grain growth, the precipitation of Cr-rich carbides and the three dimensional distribution of the chromium concentration, which vividly illuminated the effect of the grain size on the DOS and was in accordance with the experiment results.

Keywords: intergranular corrosion; degree of sensitization; cellular automaton; austenitic stainless steel.

J. Serb. Chem. Soc. 74 (11) 1303–1318 (2009)

UDC 547.263/.265+547.593:541.25:531.75; JSCS–3920; doi: 10.2298/JSC0911303R; Original scientific paper

Densities and excess molar volumes of alcohol + cyclohexylAMine mixtures

IVONA R. RADOVIĆ, MIRJANA LJ. KIJEVČANIN, ALEKSANDAR Ž. TASIĆ, BOJAN D. DJORDJEVIĆ and SLOBODAN P. ŠERBANOVIĆ

Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, P. O. Box 35-03, 11120 Belgrade, Serbia

(Received 2 April, revised 28 August 2009)

Densities of binary mixtures of 1-propanol, or 2-butanol, or 1-pentanol + cyclohexylAMine were measured at temperatures from 288.15 to 313.15 K and atmospheric pressure, while the densities for the system 2-methyl-2-pro-panol + cyclohexylAMine were measured at temperatures from 303.15 to 323.15 K and atmospheric pressure. All measurements were performed using an Anton Paar DMA 5000 digital vibrating-tube densimeter. From the experimental densities, the excess molar volumes, V^E, were calculated.

Keywords: binary mixtures; densities; excess molar volumes; alcohols; cyclohexylAMine.

J. Serb. Chem. Soc. 74 (11) 1319–1333 (2009)

UDC 504.3.054:614.78:614.71(497.11); JSCS–3921; doi: 10.2298/JSC0911319J; Original scientific paper

Physical and chemical characterization of the particulate matter suspended in aerosols from the urban area of Belgrade

JASMINKA D. JOKSIĆ, MILENA JOVAŠEVIĆ-STOJANOVIĆ, ALENA BARTONOVA*, MIRJANA B. RADENKOVIĆ, KARL-ESPEN YTTRI*, SNEŽANA MATIĆ-BESARABIĆ** and LJUBIŠA IGNJATOVIĆ***

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

*NILU, Norwegian Institute for Air Research, P.O. Box 100, 2027 Kjeller, Norway

**Public Health Institute, Bul .Despota Stefana 54, 11000 Belgrade, Serbia

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

(Received 25 February, revised 15 May 2009)

In the pharmaceutical industry, an important step consists in the removal of possible drug residues from the involved equipments and areas. The cleaning procedures must be validated and methods to determine trace AMounts of drugs have, therefore, to be considered with special attention. An HPLC–UV method for the determination of digoxin residues on stainless steel surfaces was developed and validated in order to control a cleaning procedure. Cotton swabs, moistened with methanol were used to remove any residues of drugs from stainless steel surfaces, and give recoveries of 85.9, 85.2 and 78.7 % for three concentration levels. The precision of the results, reported as the relative standard deviation (RSD), were below 6.3 %. The method was validated over a concentration range of 0.05–12.5 µg mL^-1. Low quantities of drug residues were determined by HPLC–UV using a Symmetry C18 column (150´4.6) mm, 5 µm) at 20 °C with an acetonitrile–water (28:72, v/v) mobile phase at a flow rate of 1.1 mL min^-1, an injection volume of 100 µL and were detected at 220 nm. A simple, selective and sensitive HPLC–UV assay for the determination of digoxin residues on stainless steel was developed, validated and applied.

Keywords: cleaning validation; digoxin; swab analysis; residues.

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