Classical and Advanced Chemical Sciences
Liquid-liquid extraction of cobalt (II) ions have been carried out using 0.05 M solution of N,N’-ethylenebis (4-propionyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine) (H2PrEtP) Schiff base in chloroform. Various parameters for the extraction such as effect of pH, concentrations of the extractant, cobalt(II) ion , phase ratio and synergistic effect of 4-propionyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one (HPrP) have been investigated and optimized. Extraction with single ligand was observed to have a pH1/2 of 7.05 with percentage extraction of 53.24 % corresponding to logD value of 0.0563, and optimum pH of 9.25 with percentage extraction of 98.43 %, logD value of 1.7971. The synergistic effect of HPrP on the extraction significantly lowered the pH1/2 from pH 7.05 (near neutral) to pH 6.25 (slightly acidic) with percentage extraction of 52.60 % corresponding to logD value of 0.0451. Optimum extraction of 99.30 was observed at pH 8.26 when the mixed ligands, H2PrEtP and HPrP were used. The extraction of cobalt (II) ions increased rapidly as the concentrations of the ligands H2PrEtP increased from 2.5×10-3 M to 4.0×10-2 M and that of HPrP from 2.5×10-3 M to to 2.5×10-2. Variation of the metal concentration did not have much effect on the extractions, hence the percentage extraction was relatively high over all the metal concentrations studied.
Keywords: distribution, cobalt(II), N,N’-ethylenebis(4-propionyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine), effect of pH and synergist
This study is concerned with the synthesis and characterization of γ-lactams 3a-3h. These compounds were prepared by reacting phenylsuccinic anhydride with the appropriate Schiff bases (imines) 2a-2h by heating at 51-61 ˚C in chloroform with moderate yields (70- 92 %). The structures of these γ-lactams were established on the basis of the spectral studies using IR, 1H-NMR,13C-NMR, HSQC 1H-13CNMR, and MS.
Keywords: γ-lactams, cycloaddition, imines, NMR
The liquid–liquid and liquid-solid extractions of samarium(III) from aqueous nitrate solution using D2EHPA (di-2-ethylhexyl phosphoric acid) and chelating resin “Chelex 100” as extractants is investigated to recover samarium(III) from aqueous solution. The effect of operating parameters, such as time, nitrate ion, aqueous phase acidity, concentration of the extractant, resin mass, ion strength, temperature on the samarium extraction and various acid solutions on the metal stripping from the loaded organic phase and resin are investigated. The synergistic effect showed that addition of D2EHPA to TOP (Tri-iso-octyl-phosphate) extraction was obtained for the volume ratio 4.5/0.5. The thermodynamic functions like free energy (G), enthalpy (H) and entropy (S) of extraction mechanism are discussed. Solid phase extraction is found to be more suitable than the liquid–liquid extraction for samarium(III) recovery. By liquid-liquid extraction the removed quantity was 93.26 mg g-1; for the liquid-solid extraction by Chelex 100 resin the removed quantity was 19 mg g-1. The stripping efficiency was found to be quantitative in HNO3 and HCl 1 M. The robustness of the procedure is demonstrated by the average recoveries obtained (>99.6 %) for samarium(III).
Keywords: samarium(III); Chelex 100; D2EHPA; optimization; solid phase extraction; liquid–liquid extraction; rare earth elements
The bridged peri-aroylnaphthalene compound having cyclohexane-cis-1,2-dioxy-hinge moiety connecting two benzoyl groups was successfully synthesized through the nucleophilic aromatic substitution of 1,8-bis(4-fluorobenzoyl)-2,7-dimethoxynaphthalene and cyclohexane-cis-1,2-diol. The compound consists of two ingredients in solution. The ingredients were successfully separated by repeated preparative thin layer chromatographical treatments to give stable solids. By the aid of 1H NMR spectroscopic time course tracing, the ingredients have proved to undergo mutual transformations between them to yield an equilibrium mixture of constant fraction values by standing the individual solution within several weeks, revealing that the ingredients are conformational isomers to each other. Spatial organizations of the isomers of the bridged compound in solution have been elucidated by difference NOE measurement showing rough geometry of the isomers as two “extended” forms.
Keywords: molecular structure in solution, bridged peri-aroylnaphthalene compound, cyclohexane-cis-1,2-dioxy-hinge, stable conformational isomer
The bridged peri-aroylnaphthalene compounds having 1,3-benzendioxy-hinge units were newly synthesized and the spatial organization in solution was characterized in comparison with isomeric derivatives having 1,2-benzenedioxy-hinge unit and a non-bridged analogue. 1,2-Benzenedioxy and 1,3-benzendioxy-hinge units, which connect the edge carbon atoms of aroyl groups, afford the distinct difference in rotation ability of benzene ring of aroyl groups. The sharpness/broadness and the non-equivalency of 1H NMR signals of aromatic protons demonstrate the highly congested and hinge-depending spatial organization of these bridged peri-aroylnaphthalene molecules. Furthermore, the significant magnetic field deviation of the signals in 1H NMR spectra proves the presence of effective induced magnetic field especially for the middle proton at the 2-position of the 1,3-benzenedioxy unit.
Keywords: non-coplanarly aromatic ring accumulation, bridged structure, spatial organization in solution, specific magnetic field effect
The title compound, methyl 6-amino-5-cyano-2-methyl-4-(3-nitrophenyl)-4H-pyran-3-carboxylate (C15H13N3O5), was synthesized, in 92 % yield, by one-pot multicomponent reaction of 3-nitrobenzaldehyde, malononitrile and methyl acetoacetate using 10 mol% urea as an organo-catalyst at room temperature.. It crystallizes in the triclinic space group P -1 with the unit-cell parameters: a= 8.1780(4), b= 8.3787(4), c= 11.8005(6) Å, α = 75.703(4)o, β = 86.017(4)o, γ = 72.983(4)o and Z = 2. The crystal structure was solved by direct methods using single-crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R-value of 0.0538 for 1896 observed reflections. The molecules within the unit cell are stabilized by C-H…O, N-H…O and N-H…N type of hydrogen bonding. In addition π-π interactions are also observed in the crystal structure.
Keywords: crystal structure, direct methods, hydrogen bond
A simple, sensitive and accurate spectrophotometric method is developed for the quantitative determination of metoclopramide hydrochloride and tranexamic acid drugs. The method is based on the interaction between these drugs and 9-chloroacridine reagent. The spectra of the products show maximum absorption at 470 and 479 nm and Beer’s law is obeyed in the concentration range of 2-50 and 1-40 μg mL-1 with molar absorptivity values 8.50×103 and 7074×103 L mol-1 cm-1 for above drugs respectively. The average percent recoveries are 99.90 % and 98.60 % respectively, and relative standard deviation (RSD) is ≤ 0.456 % for both drugs. In addition, the stability constant has been determined and the reaction mechanism is proposed. The method has been applied successfully for the assay of metoclopramide hydrochloride and tranexamic acid in pharmaceutical formulations and compared favourably with the amounts mentioned in formulations.
Keywords: metoclopramide hydrochloride, tranexamic acid, 9-chloroacridine, spectrophotometry
2-Amino-6-(2-oxo-2H-chromen-3-yl)-4-phenylnicotino-nitrile was reacted with cyclohexanone, formic acid, acetic anhydride, acetophenone, triethylorthoformate and hydrazine hydrate to give the corresponding pyridopyrimidine and pyridopyridine derivatives. On the other hand, 2-amino-4-(3-chloro-phenyl)-6-(2-oxo-2H-chromen-3-yl)nicotinonitrile was cyclized by reacting it with urea, thiourea, formamide, triethylorthoformate, hydrazine hydrate and cyclohexanone to give the corresponding cyclic pyridopyridine, pyridopyrimidine and pyridotriazine derivatives. The potential cytotoxicity activity of compounds 7, 8, 16 and 17 was tested against breast carcinoma cell line by SRB (Sulphorhodamine-B) assay.
Keywords: 3-Acetyl coumarin, Nicotino-nitrile, Pyridopyrimidine, Naphthyridine, Antitumor
The complex crystallizes in orthorhombic crystal system with space group Pbca. The unit cell parameters are: a=12.346(15) Å, b= 9.0931(9) Å, c= 25.136(5) Å, Z=4. The asymmetric unit comprises of half molecule with nickel(II) cation lies on an inversion centre. The Ni(II) atom is coordinated in a distorted octahedral arrangement. The variation in C–S bond lengths involving the xanthate ligands indicates the presence of double bond character due to delocalization over the two C–S bonds. The crystal structure was refined to a final reliability index (R-value) of 0.0594 for 1714 observed reflections. The amyl chain attached to the dithiocarbonato group contains disorder over two sets of sites with occupancy ratios of 0.683: 0.317. The crystal structure is stabilized by weak C-H…π interactions.
Keywords: xanthates, crystal structure, direct methods, interactions, octahedral
Pyrimidines and pyrans are the special class of heterocyclic compounds with a broad spectrum of biological activities such as anticancer, antiviral, antibacterial, antioxidant, antiallergic and antidepressant. The use of pyran derivatives is not only limitted in cosmetics, pigments and biodegradable agrochemicals but also constitute a structural unit of many natural products. Therefore researchers have synthesized these condensed heterocycles through different complex pathways as target structures for biological studies. This review focuses on the various strategies followed for the convenient synthesis of pyrimidine and pyran based heterocyclic compounds. The steps included condensation followed by cyclization or MCR, either in a step-wise manner or in one pot has been achieved successfully to obtain these two classes of heterocycles under different conditions. Diethyl oxalate, diethyl malonate, malononitrile and ethyl cyanoacetate are the most common reagents used for the synthesis of pyrimidines and pyrans appended on different heterocyclic skeletons.
Keywords: heterocycles, pyrimidines, pyrans, diethyl malonate, malononitrile
A mild and efficient method has been reported for the preparation of Schiff base through the condensation reaction of various aromatic aldehydes with substituted aromatic amines in the presence of silica supported γ-Ferrite (ferric oxide) as a heterogeneous catalyst under solvent-free conditions. and this Schiff base used for Environmentally benign synthesis followed by the reaction with chloroacetylchloride in green conditions to yield the β-lactams (a-l) with excellent yields. The advantages of this eco-friendly, mild economic method are such as simplicity of the reaction procedure, moderate to high product yields, and simple working steps, very short reaction times.
Keywords: Schiff bases, β-lactams, SiO2/γ-Fe2O3, heterogenous catalyst, 1,2,4-triazoles
A series of four chemically-similar-looking benzothiazole structures have been analyzed for their crystallographic comparison, weak intermolecular interaction analysis and lattice energy calculations. All the crystal structures are planar. However, the hydrazinyl group is slightly deviated with respect to the benzothiazole moiety in each structure. The N-H...N hydrogen bond plays an important role in the stabilization of the crystal packing in these derivatives. The related interactions of the type N-H...π, C-H...S and N....N act as an important linkage in most of the molecular pairs. A computational method has been used for the quantification of intermolecular interactions, as it allows partitioning of total interaction energy into corresponding coulombic, polarization, dispersion and repulsion contribution which facilitates a better understanding of the nature of intermolecular interactions contributing towards the crystal packing. The dispersive energy, however, lends significant contribution to the stabilization of these structures, thus making the combined nature of interaction energy in all the four molecules as predominately dispersive.
Keywords: Crystallography; Benzothiazole; Lattice energy; Intermolecular interactions; Hydrogen bonding
β-Carbonylamines were synthesized using the Mannich reaction. An aldehyde and an amine were condensed to form an imine compound, followed by the addition of concentrated sulphuric acid and acetophenone. The resulting compounds were characterised by IR, 1H and 13C NMR and mass spectroscopy.
Keywords: Mannich reaction, -carbonylamines, spectral study
The title compound, (2-methyl-phenoxy)-acetohydrazide, was synthesized by refluxing compounds o-cresol, ethyl chloroacetate and anhydrous potassium carbonate in the presence of dry acetone. The compound crystallizes in the monoclinic crystal system with space group P21/n having unit cell parameters: a = 11.5460(2), b = 6.86700(10), c = 12.7506(3)Å, β = 110.022(2)º and Z = 4 . The crystal structure was solved by direct method using single crystal x-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R- value of 0.0377 for 1619 observed reflections. In the crystal structure, molecules are linked into infinite two-dimensional networks by the N–H···N and N–H···O, C−H…O and C−H…π type of hydrogen bonds.
Keywords: Crystal structure, Direct methods, Hydrogen bond
Materials and Environmental Chemistry
The influence of polymer matrix on the activity of composite material containing cobalt nanoparticles in Fischer-Tropsch synthesis was studied. It was found that the structure of the polymer matrix affects active centers formation. Magnetometry techniques in situ and XRD confirmed the presence of the metal cobalt and its oxide phases which are the active centers of different type effect.
Keywords: Fischer-Tropsch synthesis, cobalt catalysts, polymer, polyconjugated system, magnetometry
Degradation of a non-biodegradable azo-dye (Evans blue) has been carried out by the heterogeneous photo-Fenton like processes using copper pyrovanadate (Cu3V2(OH)2O7·2H2O) as a catalyst. This catalyst was prepared by wet chemical method. These catalysts were characterized by different techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) surface area analysis. The effect of various parameters such as initial pH, concentration of dye, amount of catalyst, amount of H2O2 and light intensity on the reaction rate has also been studied. The various parameters like chemical oxygen demand (COD), conductance, pH, TDS, salinity and dissolved oxygen (DO) in the reaction mixture has been determined before and after treatment. The rate of photo-Fenton degradation of this dye followed pseudo-first order kinetics. A tentative mechanism involving •OH radicals as an oxidant for degradation of dye has been proposed.
Keywords: copper pyrovanadate, heterogeneous, degradation, photo-Fenton
Samples of particulate matter were collected during the winter season from the urban area of Tirana, Albania. Qualitative analyses of particulate matter were performed using Scanning Electron Microscope (SEM) coupled with high Energy Dispersive X-Ray Spectrometer (EDS). Based on chemical analysis and the morphology (the size and shape of particles), the most abundant groups in all sampling days were aluminosilicates (fly ash and soil particles), calcium rich and carbonaceous particles. Air mass trajectories show the presence of Saharan dust during 80 % of sampling days.
Keywords: Scanning Electron Microscope (SEM), particulate matter, morphology, elemental composition, source
Despite the development of advanced technology (or because of its development) environmental pollution, including particularly dangerous air pollutions, are really serious today. Photocatalytic air treatment has the potential for degradation of both, organic and inorganic contaminants including particularly dangerous nitrogen oxides and volatile organic compounds from indoor as well as outdoor air. Photocatalytic methods have a great advantage - do not lead to adsorption of pollutants but lead to degradation and mineralization of organic and inorganic compounds. The attractiveness of photocatalysis results also from features such as ability of using cheap and abundant sunlight as an energy source or mild conditions of process. This article briefly summaries the broad range of studies: from modeling and photoreactor design, through laboratory experiment to large scale application within recent 5 years. Our goal was not only to summarize a recent works but to demonstrate that the photocatalytic air cleaning is not a technology of a distant future, but is already technology available today.
Keywords: photocatalysis, semiconductor, air pollutants
High entropy alloys are more corrosion resistance than 316L stainless steel HEA are used as implantation material Because its unique properties and better corrosion resistances behaviors. The improved corrosion behavior could be attributed to the different chemical composition as well as the formation of a unique high entropy atomic structure with a maximum degree of disorder. It is also possible to achieve high-hardness and high-abrasion performance at high temperature, microstructure and properties of several HEA. High entropy alloys are prepared by various methods such as powder metallurgy laser cladding etc, are discussed. The corrosion resistance of HEAs and its applications also discussed.
Keywords: High entropy alloys, corrosion resistance, micro structure, properties, applications
Chemical and Biological Aspects of Life
The growth of new blood vessels contributes to numerous malignant, ischemic, inflammatory, infectious and immune disorders. There are two forms of vascular remodeling associated with physiological and pathological processes; angiogenesis and arteriogenesis. It is shown in this study that, practically in all investigated models, the process of intussusceptive angiogenesis, etc. is the first step. Chemical agents lead to the development of intussusceptive angiogenesis in liver that could be the main reason for hemodynamic disturbance.
Keywords: TEM, intussusceptive angiogenesis, liver
The objective of the present study is to evaluate the values of cancer antigen (CA15-3) and alpha feto protein (AFP) in patients with breast and prostate cancer. The results revealed the values for CA 15-3 in serum of G1 showed a highly significant increase compared to normal healthy subjects, but CA15-3 in serum of G2 was compatible with control. The results showed the value of serum AFP in G1 (was not significant different) when compared to control, while a highly significant difference in G2 was noticed when compared to healthy subjects.
Keywords: CA15-3, AFP, breast cancer, prostate cancer.
To elucidate the overall metabolism of sugars in coffee fruits, in situ metabolism of exogenously supplied 14C-glucose were investigated in segments of pericarps and seeds of two cultivars of Coffea arabica and C. canephora fruits obtained from different growth and ripening stages. The coffee fruits were categorized into five stages 1 to 5 which were corresponding to young, developing, mature (green), ripening (pink) and fully-ripened (red) fruits, respectively. The rates of uptake and metabolism of [U-14C]glucose in fruits of the stages 1–3 was higher than in fruits of stages 4–5. Release of 14CO2 which represented cellular respiration was high in both pericarp and seeds of C. arabica and C. canephora up to the stage 3, but it gradually reduced and the minimum was found in the fully ripened stage 5 fruits. The highest incorporation of radioactivity into the methanol-soluble metabolites was found in the stage 2 fruits. In pericarp, incorporation of radioactivity into the acidic component (mainly consisted of organic acids) was much higher than into basic component (mainly consisted free amino acids). In seeds, significant amounts of the radioactivity were found in the basic fractions especially at the stages 4 and 5. [U- 14C]glucose was converted to fructose and sucrose in both pericarp and seeds. Only small rate of sucrose synthesis from [14C]glucose was detected 18 h after administration, however, its relative rate is slightly increased at stages 4-5 fruits. Incorporation of radioactivity into the methanol-insoluble metabolites (mainly consisted protein starch and cell wall constituents) was found in any stages of fruits. The maximum rates were found in pericarp and seeds of developing (stage 2) fruits of C. arabica and in those at early three stages 1–3 of C. canephora. Possible metabolic routes and relative participation of carbon in different metabolite biosynthesis in coffee fruits are discussed.
Keywords: Carbohydrate, biosynthesis, metabolism, Coffea arabica, Coffea canephora
Ecological contamination is a distressing issue at the present. It deals with every aspect of our life including birth to death. The problem is not from a pinpoint source; rather it is a wide problem which contains many more aspects beyond our imagination in air, water, land etc. Many types of health hazard are in our surroundings and they gradually exposed to us. Occupational exposure to harmful substance is a very important human health hazard Industrial empowerment worsts the problem. Check on polluting industries in Dindigul District at Kulathur. A person cannot avoid this type of health hazard. Foundry industry is strongly set at Kulathur and as such polluting the area and affect the life of nearby living persons and workers. Iron is the world's most commonly used metal and can usually be found with other elements in the form of steel. The frequently recorded health disorders between iron and steel industry workers includes: respiratory and skin problems as well as noise-related hearing impairment. An assessment has been done for the occupational hazard at iron foundry through haemoglobin concentration and total erythrocyte count. A decrement in total erythrocyte count (TLC) different Leukocyte count (DLC) and haemoglobin concentration (Hb conc.) has been found in foundry workers which is alarming to take rehabilitate steps.
Keywords: health hazards, foundry industry, hemoglobin count, total leukocyte count (TLC), differential leukocyte count (DLC)
A kidney stone, also known as a renal calculus (from the Latin rēnēs, "kidneys" and calculus, "pebble") is a solid concretion or crystal aggregation formed in the kidneys from dietary minerals in the urine. It was found that mandelic acid is a good inhibitor for calcium carbonate, calcium phosphate and calcium oxalate mineralization and on increasing the strength of inhibitor solution its inhibition efficiency is increased. Mandelic acid is a more efficient inhibitor for calcium carbonate salt comparing to calcium phosphate and calcium oxalate. Simultaneous dynamic model was proved to be more efficient than reservoir dynamic model. Karaunda extract is a good inhibitor for the dissolution of kidney stone. The percentage of dissolution of powder stone is more than the whole renal stone.
Keywords: kidney stone, mandelic acid, nephrolithiasis, ureterolithiasis, cystolithiasis