European Journal of Chemistry
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Synthesis and crystal structure determination of a new 1D polymer adduct of 1,2-di(pyridin-4-yl)ethane, based on B-N dative bonded eight-membered cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane
Full text linkA novel 1D polymer of 1,2-di(pyridin-4-yl)ethane (L1), connected via B-N dative-bonded adduct with an eight-membered cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane [Ph6B2Si2O4]·L1 was synthesized and characterized. The new compound [Ph6B2Si2O4]·L1 was prepared by the reaction of cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane and bis(pyridyl)ethane in a mixture of diethyl ether and petroleum ether solvents at reflux. The 1D polymer [Ph6B2Si2O4]·L1 was characterized by single-crystal X-ray diffraction, nuclear magnetic resonance, and FT-IR spectroscopy. The single crystal X-ray diffraction studies reveal that the aforementioned compound crystalized in the monoclinic crystal system with a centrosymmetric space group of P21/n (no. 14), a = 16.5378(4) Å, b = 12.6201(3) Å, c = 20.4904(5) Å, β = 96.689(2)°, V = 4247.43(18) Å3, Z = 4, T = 173.0 K, μ(MoKα) = 0.130 mm-1, Dcalc = 1.233 g/cm3, 14630 reflections measured (4.96° ≤ 2Θ ≤ 56.424°), 8424 unique (Rint = 0.0235, Rsigma = 0.0460) which were used in all calculations, the final R1 was 0.0455 (I > 2σ(I)) and wR2 was 0.1201 (all data). Furthermore, the compound exhibits various noncovalent interactions in the crystal packing, such as intermolecular and intramolecular, as well as hydrogen bonding. This study demonstrates the potential for making novel materials via the combination of cyclodiboradisiloxanes (Lewis acid) and nitrogen-containing ligands (Lewis bases)
Synthesis and structural depiction of the isomeric benzimidazole pair and its in-silico anti-SARS-CoV-2 activities
Full text linkThe present work presents a straightforward synthesis, spectroscopic and structural depiction, and in silico anti-SARS-CoV-2 activity of an isomeric monosubstituted benzimidazole pair, 2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol (L1O) and 4-(1H-benzo[d]imidazol-2-yl)-2-methoxyphenol (L1P). The derivatives were synthesized by a coupling of aromatic aldehydes and o-phenylenediamine in ethanol under reflux. Different spectroscopic methods and X-ray structural analysis were employed to characterize the compounds. The crystal structure of L1O reveals that the o-vanillin substituted benzimidazole compound crystallizes in a monoclinic system and adopts a planar geometry. In silico anti-SARS-CoV-2 proficiencies of synthetic derivatives were evaluated against the main protease (Mpro) and nonstructural proteins (nsp2 and nsp7) of SARS-CoV-2. Molecular docking reveals the binding scores for the L1O-Mpro, L1O-nsp2 and L1O-nsp7 complexes as -11.31, -6.06 and -8.13 kcal/mol, respectively, while the binding scores for the L1P-Mpro, L1P-nsp2 and L1P-nsp7 complexes as -10.62, -5.09 and -6.91 kcal/mol, respectively, attributing the excellent conformational stability for both the isomeric benzimidazole derivatives
Single and mixed dithiocarbamato metal(III) complexes (Co, Rh, and Ir): Crystal and molecular structure description and interplay
Full text linkThis review focuses on the crystal and molecular structures of single and mixed dithiocarbamate ligands of cobalt, rhodium, and iridium in the +3 oxidation state. The complexities of their chelating and bridging modes come into play through modification of the substituents on the carbamate nitrogen atoms of the ligands and additional coordination of secondary phosphino-containing ligands, culminating in various applications such as biological, analytical, medicine, and catalysis. Other considerations include the geometrical coordination environments around the metal centres and their comparison with isostructural congeners. The distortions around the metal centres and their subsequent effects on the symmetries of bonds in the primary and secondary coordination spheres are discussed. The trans-effects of secondary P-ligands and their effects on geometrical alignment and structural stability have become valuable yardsticks in analyzing structural modifications and stabilities
Sulfonamides and sulfonate esters: Synthetic routes, proposed mechanisms, and crystallographic characterizations
Full text linkThe sulfonamide and sulfonate moieties are key structural features in many pharmaceuticals, agrochemicals, and materials and have proven useful as synthetic precursors. In this review, synthetic routes for sulfonamides and sulfonate esters were examined to gain insight into the mechanism behind the sulfonylation of amines and alcohols, which remains largely unknown and highly dependent on the reaction conditions used. Furthermore, the review delves into crystallographic characterizations of previously reported sulfonamide and sulfonate ester compounds, unraveling trends associated with crucial steric and electronic factors that influence their crystallization. This exploration not only enhances our understanding of the structural nuances of these compounds, but also paves the way for informed design strategies in synthetic and medicinal chemistry. In essence, this review endeavors to provide a holistic perspective on sulfonamides and sulfonate esters, bridging the realms of synthesis, mechanism elucidation, and structural characterization
Investigation of the antioxidant properties of Persea americana seed flour altered by the fermentation process with Lactobacillus plantarum
Full text linkThis study aims to investigate the effect of Lactobacillus plantarum fermentation on the antioxidant potential of Persea americana seed flour. The half-maximal inhibitory concentration (IC50) value of avocado seed flour after fermentation for 24, 48, and 72 h was compared with the unfermented avocado seed flour using the measurement of free radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). Additionally, the change in pH value was measured to confirm the continuous fermentation process within the desired period. The results for the DPPH assay for unfermented, 24, 48, and 72 h fermented avocado seed flour were 61.5±0.71, 51.18±0.10, 46.00±0.21, 43.73±0.21 µg/mL, respectively, which indicated a significant increase (p < 0.05) of IC50 values of avocado seed flour with the fermentation. Furthermore, with the fermentation period, there was a significant decrease in the pH value for the 72-hour fermented sample (4.15±0.03) compared to the unfermented sample (6.81±0.04). These results supported avocado seed as an important by-product source for the further development of health-promoting products, by confirming the increased antioxidant capacity of avocado seed flour after fermentation
Exploring the influence of ionic liquids on bimetallic gold nanoclusters and cellobiose through DFT analysis
Full text linkWe conducted density functional theory (DFT) studies to investigate the potential cleavage of cellobiose into smaller fragments in an ecofriendly manner using bimetallic nanoclusters in an ionic liquid (IL) medium. The presence of IL solvent layers notably influences the behavior of gold clusters during the binding. Our study involves the simultaneous consideration of metal clusters and ILs to compute cellobiose structures. Our computational analysis reveals weak interactions between IL and cellobiose, whereas metal clusters exhibit robust binding to cellobiose via glycosidic oxygen. Introducing heterogeneity in metal clusters enhances their binding to cellobiose. Incorporation of hetero-metals induces polarization in the clusters, leading to dipole formation, as indicated by the electrostatic potential maps of halogenated clusters. Among the investigated clusters, those containing [Au3Br(6IL)] exhibit notably strong binding to cellobiose, weakening the glycosidic bond by up to 7%. However, despite the strong interaction with metal clusters in an IL solvent, cleavage of the glycosidic bond remains elusive
Aqueous hydrotropes: An efficient and reusable catalyst for the synthesis of 3-carboxy-coumarin motifs at room temperature
Full text linkThe coumarin moiety plays an important role in the large number of natural products possessing different kinds of biological diversity. Coumarin carboxylic acids show a wide range of biological activities in the pharmaceutical and agricultural fields. Knoevenagel condensation is one of the important reaction pathways for synthesizing coumarin derivatives, and many methodologies have been developed to synthesize this class of compounds. A more environmentally friendly method of synthesizing 3-carboxy coumarins has been successfully carried out using 50% aqueous NaPTS hydrotropes at room temperature, along with various substituted 2-hydroxy benzaldehydes and Meldrum’s acid. This process involves Knoevenagel condensation followed by intramolecular cyclization, providing better product yields (78-95%)
Methods for synthesizing hydroxamic acids and their metal complexes
Full text linkIn previously published works, the antibacterial, antifungal, antimycobacterial and anticancer activities of hydroxamic acids (HA) and their complexes were reported. Our recently published work shows that aliphatic HA with a number of carbon atoms equal to 12 (C12) and its Fe(II), Fe(III), Ni(II), Cu(II) and Zn(II) complexes are significantly active against bacteria (Staphylococcus aureus, Escherichia coli), fungal (Candida albicans) and mycobacteria (Mycobacterium smegmatis). Furthermore, the inhibitory activities against biofilms of Mycobacterium tuberculosis, Mycobacterium bovis BCG, Mycobacterium marinum and Pseudomonas aeruginosa were observed with a large number of HA and their complexes. Suberoylanilide HA and resminostat were approved to treat cutaneous T cell lymphoma and in clinical trials to treat advanced hepatocellular carcinoma, respectively. In view of the interesting biological properties of this family of chemical compounds, the synthesis of HA has been reported in numerous research articles in recent years but this is the second review article dedicated to their synthetic methods and the first review for their complexes. The aim of this review is to highlight optimal and rational methods for the synthesis of HA and their complexes. HA are obtained in near-quantitative yields from carboxylic acid, ethyl chloroformate, N-methylmorpholine and hydroxylamine. As for their complexes, the synthesis methods described are fairly similar and would all appear to be optimal. The main criteria are the number of equivalents of HA, the type of metal salt or solvent used and the reaction conditions
Environmentally benign synthesis of substituted iodinated flavones as precursors for prenyl-/geranyl flavones from the corresponding chalcones
Full text linkFlavones have biological properties because of the existence of oxoheterocyclic ring moieties, and day by day create research interest areas because of their important biological activity. Iodine-substituted flavones were synthesized from the corresponding chalcones through an exhaustive iodination reaction. Generally, it is seen that halogenated flavones show better biological activity. Moreover, the introduction of iodine in the ring moiety facilitates the incorporation of highly active side chains, such as prenyl and geranyl groups through the formation of C-C bonds by numerous coupling reactions such as Sonogashira coupling. To achieve such target molecules, a planned chemical synthesis was conducted. For comparison, microwave irradiation (MWI) and conventional heating (CH) methods were used to synthesize a series of iodine-substituted flavone compounds with different substitutes (4a-d) from their corresponding chalcones (3a-d). Unfortunately, 3e chalcone (1-hydroxynapthalene substituted flavone) did not convert to 4e flavones. In the microwave method, a notable decrease in time required in the reaction and an increase in % yield of the reaction were remarked. Characterization and conformation of all synthesized compounds were done using ultraviolet, infrared, and nuclear magnetic resonance spectroscopy and elemental analysis