Vol 9, No 3 (2018)

September 2018

Table of Contents


Hakan Arslan
DOI 10.5155/eurjchem.9.3.i-ii.1779
Editorial Board
Hakan Arslan
DOI 10.5155/eurjchem.9.3.iii-vii.1780
Graphical Contents

Research Article

John Nicolson Low, James Lewis Wardell, Cristiane Franca da Costa, Marcus Vicinius Nora Souza, Ligia Rebelo Gomes
DOI 10.5155/eurjchem.9.3.151-160.1734

In order to further investigate the structural chemistry of oximes and to further establish the main structural arrangements adopted, we have determined the crystal structure of and carried out Hirshfeld surface calculations on three heteroaryl oximes, namely (Z)-thiophene-2-carbaldehyde oxime (1), (Z)-1H-pyrrole-2 carbaldehyde oxime (2) and (Z)-5-nitrofuran-2-carbaldehyde oxime (3). As confirmed by both techniques, the major intermolecular interactions in each compound are classical N—H···O hydrogen bonds, which link the molecules into C3 chains. Such an arrangement has been previous reported as an important aggregation mode for oximes. Secondary interactions, C—H···π and C—H···O interactions, in compounds 1 and 2, and interactions involving the nitro group oxygen atoms in compound 3 link the chains into three dimensional arrays.

Mamadou Balde, Said Ennahar, Stephanie Dal, Severine Sigrist, Alassane Wele, Eric Marchioni, Diane Julien-David
DOI 10.5155/eurjchem.9.3.161-167.1723

The extraction of bioactive compounds from medicinal plants requires methods which are as diverse as the chemical nature of the compounds themselves. In this study, a 96-well microplate was used where solvent mixtures spanning wide ranges of selectivity and polarity were tested with the objective of extracting a broad range bioactive compounds from plant material. Microplate wells were filled with plant material and the solvents and their mixtures were added. The obtained extracts were assessed in terms of their total antioxidant activity, oxygen radical absorbance capacity and effects on cell viability. An aqueous extract, generally used by traditional therapists, was also included in the study. The results showed that the extracts using methanol with acetic acid (0.1%, v:v), chloroform/ethanol, butanol/DMF, butanol/acetonitrile, ethylene glycol with acetic acid (0.1%, v:v), MTBE/DMSO, ethylene glycol, pentane/ethanol (v:v), ethanol, DMF, DMF with acetic acid (0.1%, v:v), DMSO, DMSO with acetic acid (0.1%, v:v) and THF had a higher antioxidant activity than the aqueous extract. Extracts with greater antioxidant activity than the aqueous extract were obtained largely from solvent mixtures with the exception of ethanol, DMF, DMSO and THF. The antioxidant activity obtained in TEAC varied between 1474.1±4.4 and 3183.0±16.0 μmol TE/g dry extract respectively for aqueous and THF extracts; in ORAC between 1727.7±8.4 and 2683.5±11.7 μmol TE/g dry extract for aqueous and DMSO acetic acid 1%, respectively, with mean ±SEM. In TEAC the THF extract had the highest antioxidant potential with 3183.0±16.0 μmol TE / g dry extract. The DMSO acetic acid (0.1%, v:v) extract had the highest antioxidant potential in ORAC with 2683.5±11.7 μmol TE / g dry extract. Cell viability test using β-pancreatic cells showed that only the acidified methanol extract was toxic after one hour of incubation. After 24 hours, cell viability was less than 70% for extracts using butanol/acetonitrile, MTBE/DMF, acidified methanol, pentane/ethanol and acidified DMF.

Bushra Shamshad, Rifat Ara Jamal, Uzma Ashiq, Mohammad Mahroof-Tahir, Muhammad Saleem
DOI 10.5155/eurjchem.9.3.168-177.1735

In order to further reveal the chemistry and biochemistry of chromium(III) complexes, the present work illuminates the formation of chromium(III) complexes with aroylhydrazine ligands with their physical, chemical and spectral studies. Another significant contribution of this study is the evaluation of the cytotoxic activity, antiglycation property and carbonic anhydrase inhibition study of synthesized chromium(III)-aroylhydrazine complexes. Synthesis and structural investigation of aroylhydrazine ligands (1-7) and their chromium(III) complexes (1a-7a) were carried out by using elemental analysis (C, H, N), physical (conductivity measurements) and spectral (EI-Mass, ESI-Mass, FTIR and UV-Visible) methods. These physical, analytical and spectral data supports that all chromium(III)-aroylhydrazine complexes exhibit an octahedral geometry in which ligand exhibits as a bidentate coordination and two water molecules coordinated at equatorial positions with general formula [Cr(L)2(H2O)2]Cl3. Cytotoxic investigations shows that synthesized chromium(III)-aroylhydrazine complexes were not found to be toxic against normal cells so these compounds were further studied for other biological activities. Moreover, aroylhydrazine ligands and their chromium(III) complexes were examined for their antiglycation activity in which ligands were found inactive whereas chromium(III)-aroylhydrazine complexes showed significant inhibition of the process of protein glycation. Similarly, in carbonic anhydrase inhibition studies all aroylhydrazine ligands were observed inactive while some of chromium(III)-aroylhydrazine complexes showed potential in carbonic anhydrase inhibition.

Leslaw Sieron, Agnieszka Czylkowska, Bartlomiej Rogalewicz
DOI 10.5155/eurjchem.9.3.178-181.1742

A new gadolinium(III) complex with 4,4’-bipyridine (4-bpy) and dibromoacetate ligand of general formula [Gd(4-bpy)(CBr2HCOO)3(H2O)]n, has been synthesized, crystallized and characterized by a single-crystal X-ray diffraction analysis. The gadolinium atom has an unsymmetrical eight-coordinate geometry, being coordinated by six oxygen atoms of dibromoacetate anions, one nitrogen atom of 4-bpy and one water molecule. The complex is a one-dimensional polymer as a result of dibromoacetate ligand bridging with the repeating monomeric units. There are π...π stacking interactions between the 4-bpy rings as well as O–H...O and O–H...N hydrogen bonds. Crystal Data for C16H13Br6GdN2O7 (Mw = 981.99 g/mol): triclinic, space group P-1 (no. 2), a = 9.7368(4) Å, b = 11.5416(4) Å, c = 11.7634(4) Å, α = 104.2750(10)°, β = 94.060(2)°, γ = 92.6900(10)°, = 1275.08(8) Å3, Z = 2, T = 90 K, μ(CuKα) = 28.190 mm-1, Dcalc = 2.558 g/cm3, 8399 reflections measured (7.782° ≤ 2Θ ≤ 133.18°), 4006 unique (Rint = 0.0409, Rsigma = 0.0639) which were used in all calculations. The final R1 was 0.0527 (I > 2σ(I)) and wR2 was 0.1396 (all data).

Sema Akay, Berkant Kayan
DOI 10.5155/eurjchem.9.3.182-188.1738

A lack of serotonin in the brain is associated with depression. Selective serotonin reuptake inhibitors (SSRIs) are widely used to help treat depression and associated symptoms. A method has been developed for the simultaneous determination of SSRIs by high-temperature liquid chromatography (HTLC). Citalopram, paroxetine, fluoxetine, and sertraline compounds, which are widely used as antidepressant active agents, have been chosen as SSRIs. The separation of the SSRIs have been carried out by using four different column types, including XTerra MS C18, Zorbax SB-Phenyl, Alltima C18 and Phenyl Hypersil columns, and their chromatographic performances have been evaluated. The best separation has been obtained on the Zorbax SB-Phenyl column (150 mm × 4.6 mm, 5 μm) among the four different columns studied. The separation temperature and the composition of mobile phase were examined for the optimization of chromatographic separation. Chromatographic separation of SSRIs has been carried out at temperatures ranging from 100 to 200 °C with variable flow rates (0.5-1.5 mL/min). Water:acetonitrile:acetic acid mixtures containing with 10 or 20% acetonitrile and 2% acetic acid have been used as mobile phase. The best separation was observed at volume ratio of 78:20:2 (water:acetonitrile:acetic acid) at elevated temperature on the Zorbax SB-Phenyl column. The wavelength of UV detector was set at 254 nm. All four analytes were eluted within 8 min at 200 °C. At the end of working, it was observed that the retention times of all four analytes decreased with increasing temperature and was stated that the temperature was an effective parameter for chromatographic separation. Furthermore, the relationship between retention factor and separation temperature was examined using Van’t Hoff plots and the results demonstrated with correlation coefficient greater than 0.91 on Zorbax SB Phenyl column. Consequently, the proposed HTLC method for separation and analysis of SSRIs may be used as a green alternative technique.

Viktor Vrabel, Lubomir Svorc, Julius Sivy, Stefan Marchalin, Peter Safar
DOI 10.5155/eurjchem.9.3.189-193.1758

We report the crystal and molecular structure of a new isoquinoline-derivative, namely methyl O-[(11R, 11aS)-4-oxo-1, 3, 4, 6, 11, 11a-hexahydro-2H-pyrido[1, 2-b]isoquinolin-11-yl]carbonodithioate (I), C15H17NO2S2, which crystallizes in the non-centrosymmetric space group P212121 and its absolute structure was confirmed by anomalous dispersion effects in diffraction measurements on the crystals. Two central six-membered heterocyclic rings adopt a distorted half-chair conformation. The molecules are linked by a combination of weak C—H∙∙∙O, C—H∙∙∙S, C—H∙∙∙p inter- and intra-molecular interactions resulting in a three-dimensional network in the crystal structure. Crystal Data for C15H17NO2S2 (=307.41 g/mol): orthorhombic, space group P212121 (no. 19), a = 5.2804(5) Å, b = 8.1347(17) Å, c = 35.015(4) Å, = 1504.1(4) Å3, Z = 4, T = 298(2) K, μ(MoKα) = 0.354 mm-1, Dcalc =1.358 g/cm3, 20270 reflections measured (5.522° ≤ 2Θ ≤ 50.69°), 2757 unique (Rint = 0.0346, Rsigma = 0.0203) which were used in all calculations. The final R1 was 0.0389 (I > 2σ(I)) and wR2 was 0.0965 (all data).

Ragaa Magdy, Ahmed Hemdan, Nermine Victor Fares, Maha Farouk
DOI 10.5155/eurjchem.9.3.194-201.1727

Trandolapril has no sharp peak in its zero-order spectrum, therefore it is difficult to be measured by direct spectrophotometry. In this study, direct univariate spectrophotometric methods were developed and validated for determination of Trandolapril and Verapamil combination in pure and tablet dosage forms. The first method for measuring both Trandolapril and Verapamil is Absorbance Subtraction (AS), this method depends on the presence of iso-absorptive point in the zero-order curve at 217 nm. It has the advantage of measuring the concentration of both Trandolapril and Verapamil from unified regression equation at the iso-absorptive point. The second, third and fourth methods were applied on the first order spectra of the studied drugs. Second method is Derivative Subtraction (DS) for Trandolapril and Derivative subtraction followed by spectrum subtraction (DS-SS) for Verapamil. The third and fourth methods are constant value and concentration value methods. In the concentration value method, the concentration of the drugs is determined from the graphical representation without the use of regression equations. All the developed methods were validated as per International Conference on Harmonization guidelines and the results proved that the developed methods are simple, accurate, and selective. Moreover, a statistical comparison between the developed methods and a reference method was done. Also, One-way ANOVA statistical test was done between all the proposed spectrophoto-metric methods and results showed no significant differences.

Mohammad Nasir Uddin, Jahangir Alam, Syeda Rahimon Naher
DOI 10.5155/eurjchem.9.3.202-212.1709

The adsorption capacity of chromium(III) from synthetic waste water solution by a low cost biomaterial, Jute Stick Powder (JSP)was examined. A series of batch experiments were conducted at different pH values, adsorbent dosage and initial chromium concentration to investigate the effects of these experimental conditions. To analyze the metal adsorption on to the JSP, most common adsorption isotherm models were applied. To study the reaction rate, the kinetic and diffusion models were also applied. The morphological structure and variation of functional groups in the JSP before and after adsorption was examined by scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FT-IR). Maximum chromium removal capacities of JSP was 84.34%with corresponding equilibrium uptake 8.4 mg/g from 50 mg/L of synthetic metal solution in 60 minutes of contact time at pH = 6.0 and 28 °C with continuous stirring at 180 rpm. The percent sorption of the biomass decreased with increasing concentration of metal ion but increased with decreasing pH, increasing contact time and adsorbent doses. Data for this study indicated a good correspondence with both isotherms of Langmuir and Freundlich isotherm. The analysis of kinetic indicated that Chromium was consistent with the second-order kinetic adsorption model. The rate of removal of Cr(III) ions from aqueous solution by JSP was found rapid initially within 5-30 minutes and reached in equilibrium in about 40 minutes. The investigation revealed that JSP, a low cost agricultural byproduct, was a potential adsorbent for removal of heavy metal ions from aqueous solution.

Vahidreza Darugar, Mohammad Vakili, Sayyed Faramarz Tayyari, Fadhil Suleiman Kamounah, Raheleh Afzali
DOI 10.5155/eurjchem.9.3.213-221.1713

The stability of two stable cis-enol forms in two categories of β-diketones, including para-substituted of trifluorobenzoylacetone (X-TFBA) and 1-aryl-1,3-diketone malonates (X-ADM, X: H, NO2, OCH3, CH3, OH, CF3, F, Cl, and NH2) has been obtained by different theoretical methods. According to our results, the energy difference between the mentioned stable chelated enol forms for the titled compounds is negligible. The theoretical equilibrium constants between the two stable cis-enol of the mentioned molecules are in excellent agreement with the reported experimental equilibrium constant. In addition, the effect of different substitutions on the intramolecular hydrogen bond strength has been evaluated. The correlation between Hammett para-substituent constants, σp. with the theoretical and experimental parameters related to the strength of hydrogen bond in p-X-TFBA and p-X-ADM molecules also investigated by means of density functional theory calculations. The electronic effects of para-substitutions on the intramolecular hydrogen bond strength were determined by NMR and IR data related to intramolecular hydrogen bond strength, geometry, natural bond orbital results, and topological parameters. These parameters were correlated with the Hammett para-substituent constants, σp. Good linear correlations between σp and the several parameters related to the hydrogen bond strength, in this study were obtained.

Jaykishon Swain, Amit Sahoo, Bhikari Charana Bhatta
DOI 10.5155/eurjchem.9.3.222-227.1719

The extraction behavior of Zr(IV) with tri-n-octyl amine (TOA) in kerosene was studied through a new method of solvent extraction. The mechanism of extraction and the species extracted were identified. Quantitative extraction of Zr(IV) with TOA in kerosene was studied by changing different parameters such as acid variation, diluent effect, metal concentration variation, extractant variation, effect of salting out reagent concentration and effect of temperature. It was observed that the percentage of extraction of Zr(IV) increased when the concentration of TOA and the percentage of extraction also increased when the metal ion concentration increased. The percentage of Zr(IV) became 97.4% with 0.1 M TOA from 3.0 M sulphuric acid. Kerosene was found to be effective diluent for the extraction of Zr(IV) with TOA.

Farah Samih Zeitouni, Mohammad Fawzi Amira, Gehan Moustafa El-Subruiti, Ghassan Omar Younes
DOI 10.5155/eurjchem.9.3.228-235.1728

The experimental kinetic study of aquation for both complexes bromopentaammine cobalt(III) and chloropentaammine cobalt(III) ions in the presence of tartarate solution in mixed solvent media of water with tert-butanol (10-50%, v:v) was examined spectrophotometrically at different temperatures (30-60 °C) by comparing the special effects of the leaving group of chloro and bromo on the rate constant of aquation. Comparison of kip (rate constant of ion-pairing) for both complexes and show the non-linear plots of log (kip) ion-pair rate constants against the reciprocal of the dielectric constant D. The thermodynamic analyses of the kinetic data for both complexes have been discussed in terms of solvent effect on the ion-pair aquation reactions. The obtained isokinetic temperatures of these systems indicate the existence of compensation effect arising from solute-solvent interaction. The excessive change of ΔHip* and ΔSip* with the mole fraction of the co-solvent can be recognized to the change of the physical properties of the solvent-water mixture with the solvent structure. Undersized changes in ΔGip* with the mole fraction of the co-solvent was found, representing a compensating effects between ΔHip* and ΔSip*.

Mohammad Saidur Rahman, Sayeda Shakila Alam, Kamrunnahar Happy, Mohammad Mamun Hossain, Mohammad Khademul Islam, Foni Bushon Biswas
DOI 10.5155/eurjchem.9.3.236-240.1732

A distinctive feature of polyphenolics is the possession of biological properties such as antioxidant and antimicrobial activities. Simple synthesis and study about such important class of compounds and their analogs are very important to enhance the understanding of their role in human health and diseases. Accordingly, a series of chalcones (2a-f) have been synthesized by Claisen-Schmidt condensation reaction with required acetophenones and aromatic aldehydes in high yields. The conversion of chalcones to the corresponding flavones (1a-g) taking minimal amount of dimethyl sulfoxide with iodine in presence of sulfuric acid was carried out under microwave conditions in high yields.

Mohamed Rizk, Maha Mahmoud Abou El-Alamin, Mervat Isaac Moawad
DOI 10.5155/eurjchem.9.3.241-250.1724

Simple and sensitive second derivative and synchronous spectrofluorimetric methods have been developed and validated for the quantitative determination of oxytocin and ergometrine maleate in their pure and combined dosage forms. The methods are based on the derivatization reaction of oxytocin with fluorescamine reagent, which yielded a highly fluorescent compound measured at 486 nm after excitation at 390 nm. Ergometrine was directly measured in combination with oxytocin, since it exhibits native fluorescence at 421 nm after excitation at 300 nm. Quantitation of oxytocin in presence of ergometrine was also successful at 482 and 477 nm using second derivative and synchronous spectrofluorimetry, respectively. Different experimental parameters were studied and optimized. The relative fluorescence intensity versus concentration plot was rectilinear over the range of 0.04-0.75 and 5-100 ng/mL for oxytocin and ergometrine, respectively. The methods were successfully applied for the determination of both drugs in their prepared combined ampoules. The methods were validated and compared with the reference chromatographic method; they revealed good accuracy and reproducible results. The proposed methods showed high accuracy and sensitivity, with no requirement of multiple steps or previous chemical separation.

Mohamed Rizk, Maha Sultan, Mona Elshahed, Mourad Ali
DOI 10.5155/eurjchem.9.3.251-257.1731

A stability indicating spectrofluorimetric method is developed for the determination of naratriptan hydrochloride in pharmaceutical formulation. The proposed method is based on investigation of the native fluorescence spectral behaviour of the drug in aqueous phosphate buffer (pH = 7.0±0.2).The fluorescence intensity is measured at 355.0 nm after excitation at 230.0 nm. The fluorescence-concentration plot is linear over the concentration range 8.0-80.0 ng/mL, with lower detection limit of 2.6 ng/mL and quantification limit of 7.6 ng/mL. The method is successfully applied to the analysis of the studied drug in its commercial tablet. Furthermore, the proposed method is applied in dissolution study of tablet; the results are in good agreement with those obtained with the reference method. The proposed method is approved to be a stability-indicating assay after exposure of the drug to different forced degradation conditions, such as acidic, alkaline and oxidative conditions, according to International Conference on Harmonization guidelines.

Ines Fitouri, Habib Boughzala
DOI 10.5155/eurjchem.9.3.258-268.1762

The title compounds are members of the M2O-CuO-P2O5 system (M = Li, Na, K and Rb), where the lithium, sodium, potassium, rubidium and cesium phases have already been structurally characterized. The studied diphosphates LiNaCuP2O7, LiKCuP2O7 and Rb0.5Na1.5CuP2O7 belong to a large family of materials of general formula, MM’CuP2O7 (M, M’ = Monovalent cation) where the elements M and M’ ionic radii are decisive in the structural type determination. They were synthesized by solid-state reactions. The X-ray structural analysis show that these compounds crystallize in the P21/n monoclinic lattice where the CuO5 pyramidal square are linked to nearly eclipsed P2O7 groups by corner sharing to build up corrugated layers [CuP2O7]2- extending perpendicularly to [010]. The Li+, Na+, K+ and Rb+ cations reside in the interlayer space and in cavities delimited by the anionic network. In this study, the synthesis, the structure, the powder diffraction, the infrared spectroscopy, the thermal analysis (DTA/TGA) and a structural comparison are presented. The structural models were validated by Bond Valence-Sum (BVS) and charge distribution (CHARDI) analysis.

Yousef Mohammad Hijji, Rajeesha Rajan, Hani Darwish Tabba, Imad Ali Abu-Yousef, Said Mansour, Hamdi Ben Yahia
DOI 10.5155/eurjchem.9.3.269-274.1751

Nitriles are versatile organic precursors in organic synthesis and have numerous applications. An efficient microwave assisted method for conversion of aromatic aldehydes to the corresponding nitriles is reported. Aldehydes are readily converted to oxime followed by acetylation and acetic acid elimination to provide nitriles in good yields within minutes. The method proved to be efficient for the synthesis of aromatic and heterocyclic nitriles. The reaction proceeds smoothly by microwave at 150 °C for 5 minutes. The obtained products are isolated simply by filtration or extraction.

Maysoon Mohammed Almahdi, Ahmed Elsadig Mohamed Saeed, Nadia Hanafy Metwally
DOI 10.5155/eurjchem.9.3.275-280.1765

A quantitative structure-activity relationships (QSAR) studies were carried out by correlating activity against human breast adenocarcinoma cell line MCF-7 of series of α,β-unsaturated carbonyl compounds with their physicochemical descriptors using multiple linear regression method. The predictability of the QSAR model was estimated using internal and external predictivity methods. The best QSAR model was selected, having the squared correlation coefficient r2 = 0.84684, correlation coefficient r = 0.9202, standard deviation s = 0.38484, and cross-validated squared correlation coefficient Q2 = 0.7621. Model obtained was used to predicted the activity against breast cancer for a set of designed α,β-unsaturated carbonyl compounds (A1-A16). Docking studies was performed for A1-A16 compounds to evaluated their inhibition on c-Met kinase, which has been overexpressed in a number of cancers.