European Journal of Chemistry

The title compound 5-methyl-1,3-bis(3-nitrobenzyl)pyrimidine-2,4(1H,3H)-dione was obtained by reaction of thymine with 3-nitrobenzylbromide in the presence of cesium carbonate. Characterization of the product was achieved by NMR spectroscopy and its stability was probed in basic condition using UV-Visible analysis. Furthermore, the molecular structure was confirmed by X-ray diffraction analysis. The compound crystallizes in orthorhombic Pna21 space group with unit cell parameters a = 14.9594 (15) Å, b = 25.711 (3) Å, c = 4.5004 (4) Å, V = 1731.0 (3) ų and Z = 4. The crystal packing of the title compound is stabilized by intermolecular hydrogen bond, π···π and C−H···π stacking interactions. The intermolecular interactions were furthermore analyzed through the mapping of different Hirshfeld surfaces. The two-dimensional fingerprint revealed that the most important contributions to these surfaces come from O···H (37.1%), H···H (24%) and H···C/C···H (22.6%) interactions. The interaction energies stabilizing the crystal packing were calculated and were presented graphically as framework energy diagrams. Finally, the energy-framework analysis reveals that π···π and C−H···π interactions energies are mainly dispersive and are the most important forces in the crystal.

In order to increase the activity and selectivity towards to light olefins in the Fischer-Tropsch synthesis, new support for the role of iron (Fe) are presented. Thus, SBA-15 was synthetized and doped with different alkaline metals preserving the structural characteristics of the mesoporous solid. The samples were characterized by X-ray diffraction at low angles, N₂ adsorption, atomic absorption spectroscopy, CO₂ desorption at programmed temperature and isopropanol test. The alkaline metals (Li, K and Cs) introduction into the channels of the solid, generate basic sites of different strength that are not present in the SBA-15 without doping and do not produce significant changes in the structural and textural properties of the SBA-15, only a densification in the walls of the channels is evidenced. According to the alkaline metal used and through CO₂ adsorption and isopropanol decomposition, it was possible to established the order by the total number of sites: Li >> K » Cs, and the force order for both types of sites (weak and intermediate): Li > Cs > K.

Copper(II) α-benzoin oxime complex was synthesized by the reaction between copper(II) benzoate and α-benzoin oxime. The poly methacrylic acid-ethylene glycol dimethacrylate (MAA-EGDMA) was applied as support of copper complex catalyst for oxidation of alcohols to aldehydes using NaClO. The structure and morphology of immobilized Cu(II)-benzoin oxime have been studied by using different analysis including Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM) and Thermal Gravimetric Analysis (TGA). The yield of aldehydes was determined by Gas Chromatography (GC) analysis. The immobilized Cu(II)-benzoin oxime indicated a high catalytic activity compared to its absence for the alcohol oxidation with sodium hypochlorite. The effect of the reaction time and temperature, the solvent type, the amounts of catalyst and NaClO were optimized to obtain maximum yield. The prepared catalyst had various benefits such as being inexpensive, environmentally friendly manner, recyclable, reducing the reaction time and increasing the yield. A reaction mechanism is proposed for oxidation of alcohols in the presence of the catalyst.

In this study, a series of 1,2,4-triazol-3-carbohydrazide derivatives and compound of 1,2,4-triazole-3-(4H)-thion have been synthesized. Structures and purity of the new compounds were confirmed by the use of their chromatographic and spectral data besides microanalysis. Four different bacterial stains for the study of the biological activity of compounds 6g, 7c, 7g and 7i; two Gram-positive strains, and two Gram-negative strains have been used. Compound 6g was found to be the most active of the four tested compounds against Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus, with an inhibition zone diameter of 16, 9, and 10 mm, respectively. Calculating the minimal inhibitory concentration value (MIC) for the positive drugs who formed an inhibition zone in the agar well diffusion method, we found that both compounds 6g and 7i were the most active of the four tested compounds against Pseudomonas aeruginosa and Bacillus cereus with an MIC value of 0.5 µg/mL for both bacteria. These results suggest that these two compounds could be considered as potential antibacterial agents against a range of bacteria.

A new series of imidazole linked thiazolidinone hybrid molecules was designed and subsequently synthesized through a feasible, three step reaction protocol. The structures of these molecules were established using FT-IR, ¹H NMR, ¹³C NMR and HRMS techniques. In vitro susceptibility tests against some Gram positive (Staphylococcus aureus and Bacillus subtilis) and Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) exhibited broad spectrum potency of the molecules. The most potent molecule (S2A7) amongst the screened molecules, showed minimum inhibitory concentration (MIC) value not less than 2.0 µg/mL which was at par with the reference drug Streptomycin. Structure activity relationships revealed nitro and chloro groups being crucial for bioactivity when present at meta position of arylidene ring in 3-(3-(imidazol-1-yl)propyl)-5-(benzylidene)-2-(phenylimino)thiazolidin-4-one. Deoxyribonucleic acid (DNA)and bovine serum albumin (BSA) binding studies for S2A7 under simulated physiological pH were probed using UV-Visible, fluorescence quenching, gel electrophoresis and molecular docking techniques. These studies established that S2A7 has strong binding affinity towards DNA and binds at the minor groove of DNA with binding constant (K_b) of 0.1287×10² L/mol. Molecular docking simulations of S2A7 with DNA and BSA predicted binding affinity of -9.2 and -7.2 kcal/mol, respectively. Van der Waals forces and hydrogen bonding interactions were predicted as the main forces of interaction. With DNA, S2A7 exhibited specific binding affinity towards adenine-thiamine base pairs. The compound S2A7 forms a stable complex with BSA by binding at subdomain IIIA implying high bio-distribution of the compound.

Gadolinium-based contrast agent interacts with the human body temporarily and improves the pictures of inside of the body produced by magnetic resonance imaging, computed tomography, X-rays and ultrasound and it also helps to distinguish the normal from abnormal conditions. In this study, the authors developed a simple, rapid, reliable and robust inductively coupled plasma mass-spectrometry method for estimation of gadolinium in gadolinium-based contrast agents to check the drug quality and ensure the patient safety. The samples were digested at 160°C using the microwave digestion system and the gadolinium was extracted in 0.4% (w/w) nitric acid. Interference of deposited gadolinium on sample cone and skimmer cone were investigated and evaluated. The developed method was validated as per ICH Q2 (R1) guideline and USP<730>. The precision was evaluated with six independent assays of gadolinium in each gadolinium-based contrast agent. The test method was found linear (r² > 0.999) with five different levels covered from 25~200%, and accurate, mean recoveries were 92.5~107.5% at three different levels covered from 50~150%. The robustness was performed by changing the nitric acid concentration (0.4±0.04%, w/w) in diluent system. This method is suitable to quantitatively determine the amount of gadolinium in gadolinium-based contrast agent of drug products in presence of excipients used in formulation and also in drug substance.

In regards to the Cannizzaro reaction and its peculiar mechanism, some researchers have presented a free radical mechanism for the Cannizzaro reaction, while others have found that it is feasible through an ionic mechanism, but the actual mechanism has not been finalized yet. The researchers have given the proof of both the mechanisms through their papers published. Actually, Cannizzaro reaction may occur through both mechanisms depending on both molecular structure and different conditions which are yet to be explained. Recently published papers describe that free radical mechanism occurs only in a heterogeneous medium, while an ionic mechanism occurs in a homogeneous medium. We revealed no explanation of the molecular structure-based reason, responsible for a radical or an ionic mechanism. The present paper reviews not only homogeneous/heterogeneous medium conditions but also molecular structure-based facts, which may be responsible for the Cannizzaro reaction to occur through the radical or ionic mechanism, and that may be acceptable to the scientific society. Besides, Density Functional Theory study using Gaussian software was also involved in the explanation of the molecular structure, responsible for one of the two mechanisms. Also, the present paper specifies all points related to future perspectives on which additional studies are required to understand the actual mechanism with a definite molecular structure in the different reaction media.

The triptan drug such as eletriptan in combination with hydrochloride (ETP) is a 5-HT₁ receptor agonist used to treat the migraine headache. Human serum albumin (HSA), the fundamental serum protein, executes various functions, that includes transporting and binding of many ligands. HSA binding interaction with ETP is elucidated from molecular docking in composite with fluorescence (emission, 3D and synchronous), UV-vis and FT-IR spectroscopy at 296, 304 and 312 K (pH = 7.40). ETP after interaction modified the HSA secondary structure and its micro-environments. Energy transfer and thermodynamic parameters were evaluated. Various quenching and binding constants were computed for formed ETP-HSA complex. The dominant interactive forces for ETP and HSA binding are hydrogen bonds join up with van der Waals extent possibly at site III (IB). The presence of Ca²⁺, Co²⁺, Na⁺, Mg²⁺ and Fe³⁺ ions significantly affected binding ability of ETP towards HSA. The essentialness of this investigation is beneficial in life sciences, medicinal chemistry, pharmaceutical industry and clinical medicine.

New benzoylthiourea derivative, N-(4-formylpiperazine-1-carbonothioyl)benzamide was prepared by the reaction of benzoylisothiocyanate with 1-piperazinecarboxaldehyde in acetone as solvent. The compound was characterized by FT-IR and multinuclear ¹H and ¹³C NMR spectroscopy techniques. The benzoylthiourea molecule was obtained in crystalline form by recrystallization in DMSO. Single crystal X-ray diffraction study indicates that compound crystallized in triclinic crystal system and crystal data for C₁₃H₁₅N₃O₂S, space group P-1 (no. 2), a = 7.3016(9) Å, b = 7.7380(9) Å, c = 12.9815(16) Å, α = 103.581(4)°, β = 102.153(4)°, γ = 102.409(4)°, V = 669.46(14) Å³, Z = 2, T = 296(2) K, μ(MoKα) = 0.243 mm^-1, Dcalc = 1.376 g/cm³, 31184 reflections measured (6.72° ≤ 2Θ ≤ 53.46°), 2822 unique (R_int = 0.0582) which were used in all calculations. The final R₁ was 0.0501 (>2σ(I)) and wR₂ was 0.1493 (all data). Intramolecular N-H···O hydrogen bond is stabilized the trans geometry of the thiono and the carbonyl groups. The heterocyclic piperazine ring makes a dihedral angle of 48.50(15)° with the benzene ring. Antioxidant test by DPPH method showed that compound exhibits good antioxidant activity of about 75%.

A simple, ultra-sensitive, and highly selective spectrophotometric method has been established for the trace quantification of zinc (Zn), using 2-hydroxynaphthaldehyde benzoylhydrazone (HNABH). Zn forms a pale yellowish-green complex (maximum absorption at 426 nm) with HNABH (1:1, v:v) in a marginally acidic solution (0.00005-0.00023 M H₂SO₄). The average molar absorption coefficient and Sandell’s sensitivity were found: 2.87×10⁵ L/mol.cm and 12 ng/cm² of Zn, respectively. The observed linearity range for Zn was 0.01-50 mg/Lwith a detection limit of 1 µg/L. The analysis of biological, food, and vegetable samples using the suggested method were found to be in tremendous accord with those acquired by Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The method has high precision and accuracy (s = ±0.01 for 0.5 mg/L). The limit of quantification of the proposed method was 10 µg/L.

Pharmaceutical chemistry deals with the process of isolating organic compounds from natural sources or chemically synthesizing them in order to explore potential drugs. Drugs are small molecules, used to prevent or treat various diseases. Of several lead molecules, only few of them reach clinical trial phases and emerge as effective drugs, whereas the majority will be eliminated at different stages. On the other hand, due to the lack of proper identification of their pharmacokinetic properties and biological potential, many small molecules fail to reach this stage. This could be because of the fact that it is either time consuming and costly or there is full of uncertainty due to lack of analyses that are necessary for the confirmation. In the post-genomic era, computational methods have been implemented in almost all stages of drug research and development owing to the drastic increase in the available knowledge about small molecules and the target biomacromolecule. This includes identifying the suitable and specific targets for drug candidates, lead discovery, lead optimization and ultimately preclinical phases. In this context, numerous websites have become highly valuable and influence the drug development and discovery process. Here, we have attempted to bring together some of the online computational approaches and tools that are available to facilitate research efforts in the field of drug discovery and drug design. The output information from these tools is extremely helpful in selecting and deciding about the future direction or specific path needed to be followed by the researchers. These computational methods are indeed help to focus the intended research in the right direction. As detailed in this review, the information provided about the servers and methods should be useful throughout the process of screening of synthesized or chemical database originated small molecules to find the appropriate targets along with the active sites without depending on any commercial tools or time-consuming and costly assays. It should however be remembered that the bioinformatics-based prediction cannot completely replace the wet lab data of chemical compounds or specific assays.