Showing papers in "Monatshefte Fur Chemie in 2018"
TL;DR: This review provides a comprehensive resource, summarizing a broad range of important quinolone applications with great utility as a resource concerning both chemical modifications and also novel hybrid bifunctional therapeutic agents.
Abstract: This review is aimed to provide extensive survey of quinolones and fluoroquinolones for a variety of applications ranging from metal complexes and nanoparticle development to hybrid conjugates with therapeutic uses. The review covers the literature from the past 10 years with emphasis placed on new applications and mechanisms of pharmacological action of quinolone derivatives. The following are considered: metal complexes, nanoparticles and nanodrugs, polymers, proteins and peptides, NO donors and analogs, anionic compounds, siderophores, phosphonates, and prodrugs with enhanced lipophilicity, phototherapeutics, fluorescent compounds, triazoles, hybrid drugs, bis-quinolones, and other modifications. This review provides a comprehensive resource, summarizing a broad range of important quinolone applications with great utility as a resource concerning both chemical modifications and also novel hybrid bifunctional therapeutic agents.
62 citations
TL;DR: In this paper, the capacity (moles gas per kg solvent) at a given temperature and partial pressure of the gas, and the corresponding Henry's law constant is described by means of the capacity of deep eutectic solvents (DES) for the reversible capture of carbon dioxide and sulfur dioxide.
Abstract: Deep eutectic solvents (DES) are competitive solvents for the reversible capture of carbon dioxide and sulfur dioxide. They are ‘green’, i.e., friendly to the environment and inexpensive to produce. The solubilities of these gases in a variety of DES have been collected from the literature and reviewed and are described by means of the capacity (moles gas per kg solvent) at a given temperature and partial pressure of the gas, and the corresponding Henry’s law constant. The saturation molalities at 0.1 MPa partial gas pressure for the solubility of CO2 in the commonly used choline chloride-based DES at 313.15 K are between 0.2 and 0.7 mol kg−1. The corresponding values for SO2 are some order of magnitude larger. The gas solubility increases linearly with the partial pressure but diminishes with increasing temperatures, the negative enthalpy of solution showing the process to be exothermic.
34 citations
TL;DR: Quinoline-2,4-diones reacted with 2-(2-oxo-1,2-dihydroindol-3-ylidene)malononitrile in pyridine to give 2′-amino 2,5′-dioxo-5′,6′-dimethylpoly(indoline-3,4′-pyrano[3,2c]quinoline)-3′-carbonitriles in good to excellent yields as mentioned in this paper.
Abstract: Quinoline-2,4-diones reacted with 2-(2-oxo-1,2-dihydroindol-3-ylidene)malononitrile in pyridine to give 2′-amino-2,5′-dioxo-5′,6′-dihydrospiro(indoline-3,4′-pyrano[3,2-c]quinoline)-3′-carbonitriles in good to excellent yields The structures of all new products were proven using one- and two-dimensional NMR, IR, and mass spectral data, and in five cases X-ray structural analyses The possible mechanism for the reaction is also discussed
27 citations
TL;DR: A series of 4-(1-azolyl)aniline derivatives (azole,= izole, benzimidazole and pyrazole) underwent diazotization reaction by NaNO2/HCl and were consequently treated with aromatics such as phenol, N,N-dimethylaniline, 2-naphthol, and 8-hydroxyquinoline to give the coupled azo compounds.
Abstract: A series of 4-(1-azolyl)aniline derivatives (azole = imidazole, benzimidazole, pyrazole, 3-methylpyrazole, and 4-methylpyrazole) underwent diazotization reaction by NaNO2/HCl. The diazonium salts were consequently treated with aromatics such as phenol, N,N-dimethylaniline, 2-naphthol, and 8-hydroxyquinoline to give the coupled azo compounds. The antibacterial activities of some of the products were evaluated against Gram-negative [Escherichia coli (ATCC 25922)] and Gram-positive [Staphylococcus aureus (ATCC 25923)] bacteria. Moreover, in vitro examinations for a series of the products corroborated anticancer activities against MCF7 breast cancer cells.
25 citations
TL;DR: By acid-catalyzed reaction of substituted isatins with Girard’s reagent T, new water-soluble isatin-3-acylhydrazones were obtained with high yields and their antimicrobial activity was evaluated.
Abstract: By acid-catalyzed reaction of substituted isatins with Girard’s reagent T, new water-soluble isatin-3-acylhydrazones were obtained with high yields. Their antimicrobial activity was evaluated. Selective activity against Gram-positive bacteria (S. aureus 209p and B. cereus 8035) and yeast-like fungus Candida albicans 855–653 along with low hematoxicity was established.
25 citations
TL;DR: The synthesized Schiff base ligand and its metal complexes demonstrate mild antibacterial and antifungal activities against these organisms and against two pathogenic bacteria as Gram-positive and Gram-negative bacteria.
Abstract: A hydrazone Schiff base ligand was synthesized by the condensation of 3-formyl-4-hydroxycoumarin and oxalyldihydrazide in the molar ratio 2:1. The Schiff base ligand acts as a mono-, bi-, tri- or even tetradentate ligand with metal cations in the molar ratios 1:1 or 2:1 (M:L) to yield either mono- or binuclear complexes as keto or enol isomers, where M = Co(II), Ni(II), Cu(II), VO(IV), and Fe(III). The ligand and its metal complexes were characterized by elemental analyses, IR, 1H NMR, mass, and UV–Vis spectroscopy. Furthermore, the magnetic moments were calculated from the measured electric conductivities of the complexes. According to the received data, the dihydrazone ligand contains one or two units of ONO domains and can bind to the metal ions via the azomethine nitrogen, the carbonyl oxygen atoms, and/or the phenolic oxygen atoms. Electronic spectra and the magnetic moments of all complexes show that the complexes’ geometries are either octahedral, tetrahedral, square planar, or square pyramidal. Cyclic voltammograms of the mononuclear Co(II) and Ni(II) complexes show quasi-reversible peaks. Tests against two pathogenic bacteria as Gram-positive and Gram-negative bacteria for both, the Schiff base ligand and its metal complexes were carried out. In addition, also one kind of fungi was tested. The synthesized complexes demonstrate mild antibacterial and antifungal activities against these organisms.
23 citations
TL;DR: In this article, an efficient, mild, and eco-friendly procedure of 1-aminoalkyl-2-phenol/Betti base from one-pot three-component condensations of aldehyde, phenol, and morpholine in the presence of sulfated polyborate catalyst, under a solvent-free condition at 100°C, is described.
Abstract: In this work, efficient, mild, and eco-friendly procedure of 1-aminoalkyl-2-phenol/Betti base from one-pot three-component condensations of aldehyde, phenol, and morpholine in the presence of sulfated polyborate catalyst, under a solvent-free condition at 100 °C, is described. The key advantages of the present method are short reaction time, high yields, aqueous work-up procedure, low cost, stable, reusable catalyst, and solvent-free reaction conditions.
23 citations
TL;DR: In this paper, the serum-binding preferences of two metallodrugs with anticancer activities in vivo were studied in mice bearing a CT-26 tumor, namely organoruthenium compound plecstatin-1 and isosteric osmium analog.
Abstract: Size-exclusion chromatography–inductively coupled plasma–mass spectrometry (SEC–ICP–MS) was used to study the serum-binding preferences of two metallodrugs with anticancer activities in vivo, namely the organoruthenium compound plecstatin-1 and its isosteric osmium analog. The complexes were administered intraperitoneally into mice bearing a CT-26 tumor. Comparing the total metal content of mouse whole blood and serum underlined that the metallodrugs are mainly located in serum and not in the cellular fraction of the blood samples. In mouse serum, both compounds were not only found to bind extensively to the serum albumin/transferrin fraction but also to immunoglobulins. Free drug was not observed in any of the samples indicating rapid protein binding of the metallodrugs. These findings were validated by spiking human serum with the respective compounds ex vivo. An NCI-60 screen is reported for the osmium analog, which revealed a relative selectivity for cancer cell lines of the ovary and the central nervous system with respect to plecstatin-1. Finally, a COMPARE 170 analysis revealed disruption of DNA synthesis as a possible treatment effect of the osmium-based drug candidate.
23 citations
TL;DR: Compounds possessing a very high antibacterial activity, comparable to that of a commercial antibacterial agent oxytetracycline, against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus were identified.
Abstract: Benzimidazole derivatives are potential candidates for drug development. They are efficiently synthesized and possess various biological properties including antibacterial activity. A series of functionalized benzimidazole derivatives bearing N-(4-chloro- or fluorophenyl)pyrrolidin-2-one or N-(4-chloro- or fluorophenyl)aminobutanoic acid moiety were synthesized. Compounds possessing a very high antibacterial activity, comparable to that of a commercial antibacterial agent oxytetracycline, against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus were identified. Some of the synthesized compounds exhibited significant antioxidant activity.
22 citations
TL;DR: The reaction between chitin-derived heterocycle 3-acetamido-5-acetylfuran and aliphatic ketones results in the formation of a novel dihydrodifuropyridine scaffold as discussed by the authors.
Abstract: The reaction between the chitin-derived heterocycle 3-acetamido-5-acetylfuran and aliphatic ketones results in the formation of a novel dihydrodifuropyridine scaffold.
22 citations
TL;DR: The developed methodology for classification of Not From Concentrate (NFC) juices is a promising analytical tool to ensure the authenticity and good quality of juices.
Abstract: The food authenticity assessment is an increasingly important issue in food quality and safety. The application of an electronic nose based on ultra-fast gas chromatography technique enables rapid analysis of the volatile compounds from food samples. Due to the fact that this technique provides chemical profiling of natural products, it can be a powerful tool for authentication in combination with chemometrics. In this article, a methodology for classification of Not From Concentrate (NFC) juices was presented. During research samples of 100% orange juice, 100% apple juice, as well as mixtures of these juices with known percentage of base juices were tested. Classification of juice samples was carried out using unsupervised and supervised statistical methods. As chemometric methods, Hierarchical Cluster Analysis, Classification Tree, Naive Bayes, Neural Network, and Random Forest classifiers were used. The ultra-fast GC technique coupled with supervised statistical methods allowed to distinguish juice samples containing only 1.0% of impurities. The developed methodology is a promising analytical tool to ensure the authenticity and good quality of juices.
TL;DR: For the first time, the regiochemistry of this reaction was unambiguously proven by X-ray structural analysis and the quantum-chemical calculation performed at the M06-2X/6-31G(d) (PCM) theoretical level affords a basis for explaining the course of reaction as well as the nature of transition states.
Abstract: 5-(Nitromethyl)-3-phenyl-4,5-dihydroisoxazole was obtained as a product of a high-yielding [3 + 2] cycloaddition reaction of in situ-generated benzonitrile N-oxide and 3-nitroprop-1-ene. For the first time, the regiochemistry of this reaction was unambiguously proven by X-ray structural analysis. The quantum-chemical calculation performed at the M06-2X/6-31G(d) (PCM) theoretical level affords a basis for explaining the course of reaction as well as the nature of transition states. Next, further DFT calculations together with spectral data shed light on structural aspects of the product.
TL;DR: A new series of 1,2,4-triazine unsymmetrical disulfanes were prepared and evaluated as anticancer activity compounds against MCF-7 human breast cancer cells with some of them acting as low micromolar inhibitors.
Abstract: A new series of 1,2,4-triazine unsymmetrical disulfanes were prepared and evaluated as anticancer activity compounds against MCF-7 human breast cancer cells with some of them acting as low micromolar inhibitors. Evaluation of the cytotoxicity using an MTT assay, the inhibition of [3H]-thymidine incorporation into DNA demonstrated that these products exhibit cytotoxic effects on breast cancer cells in vitro. The most effective compounds with 59 and 60 µM compared to chlorambucil with 47 µM were disulfanes bearing methyl and methoxy substituent in an aromatic ring. Furthermore, all new 14 compounds were obtained with 22–74% yield via mild and efficient synthesis of the sulfur–sulfur bond formation from thiols and symmetrical disulfanes using 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). The molecular structure of the newly obtained compounds was confirmed by X-ray analysis. The conformational preferences of disulfide system were characterized using theoretical calculations at DFT level and statistical distributions of C–S–S–C torsion angle values based on the Cambridge Structural Database (CSD). The DFT calculations and CSD searching show two preferential conformations for C–S–S–C torsion angle close to ± 90° and relatively large freedom of rotation on S–S bond in physiological conditions. The molecular docking studies were performed using the human estrogen receptor alpha (ERα) as molecular target to find possible binding orientation and intermolecular interactions of investigated disulfanes within the active site of ERα. The S…H–S and S…H–C hydrogen bonds between sulfur atoms of bisulfide bridge and S–H and C–H groups of Cys530 and Ala350 as protein residues play crucial role in interaction with estrogen receptor for the most anticancer active disulfane.
TL;DR: It is suggested to use the Debye–Einstein integral fit as a standard method to describe heat capacities in the range between 0 and 300 K so that the derived thermodynamic functions are obtained on the same theory-related semi-empiric basis.
Abstract: Thermodynamic data of various crystalline solids are assessed from low temperature heat capacity measurements, i.e., from almost absolute zero to 300 K by means of semi-empirical models. Previous studies frequently present fit functions with a large amount of coefficients resulting in almost perfect agreement with experimental data. It is, however, pointed out in this work that special care is required to avoid overfitting. Apart from anomalies like phase transformations, it is likely that data from calorimetric measurements can be fitted by a relatively simple Debye–Einstein integral with sufficient precision. Thereby, reliable values for the heat capacities, standard enthalpies, and standard entropies at T = 298.15 K are obtained. Standard thermodynamic functions of various compounds strongly differing in the number of atoms in the formula unit can be derived from this fitting procedure and are compared to the results of previous fitting procedures. The residuals are of course larger when the Debye–Einstein integral is applied instead of using a high number of fit coefficients or connected splines, but the semi-empiric fit coefficients keep their meaning with respect to physics. It is suggested to use the Debye–Einstein integral fit as a standard method to describe heat capacities in the range between 0 and 300 K so that the derived thermodynamic functions are obtained on the same theory-related semi-empiric basis. Additional fitting is recommended when a precise description for data at ultra-low temperatures (0–20 K) is requested.
TL;DR: In this article, the enantioselective separation of phenylalanine was attained in reversed phase mode at 45°C with acetonitrile/water containing 1.5% acetic acid (90/10, v/v) as mobile phase (resolution value was 1.49, selectivity factor were 1.38).
Abstract: l-Phenylalanine molecularly imprinted polymers were synthesized by bulk polymerization. Methacrylic acid and acrylamide were tested as functional monomers. Ethanol and acetonitrile were used as porogenic solvents. Optimal composition of polymerization mixture was methacrylic acid, template, and ethylene glycol dimethacrylate in molar ratio 1:5:26. MIP was applied as HPLC chiral stationary phase. The influences of the mobile phase composition, flow rate, column temperature, and column length on the efficiency of enantioseparation were investigated. The enantioselective separation of phenylalanine was attained in reversed phase mode at 45 °C with acetonitrile/water containing 1.5% acetic acid (90/10, v/v) as mobile phase (resolution value was 1.49, selectivity factor was 1.38). Applicability of polymeric stationary phase prepared for l-phenylalanine was tested for analysis of dietary supplement sample. The UV detection limits for both enantiomers were 1 mg cm−3 (S/N = 3). Good linearity was observed from 1 to 10 mg cm−3.
TL;DR: In this paper, a novel bioactive 2-methylindole-substituted pyrido[2,3-d]pyrimidine derivatives were synthesized through an unprecedented one-pot three-component reaction of aromatic aldehydes, 6-amino-N, N-dimethyuracil, 3-(2-methyl-1H-indol-3-yl)-3-oxopropanenitrile in the presence of Fe3O4@SiO2-IL nanocatalyst as an efficient and magnetically retri
Abstract: Novel bioactive 2-methylindole-substituted pyrido[2,3-d]pyrimidine derivatives were synthesized through an unprecedented one-pot three-component reaction of aromatic aldehydes, 6-amino-N,N-dimethyuracil, 3-(2-methyl-1H-indol-3-yl)-3-oxopropanenitrile in the presence of Fe3O4@SiO2-IL nanocatalyst as an efficient and magnetically retrievable catalyst. The assessment of antibacterial activity exhibited promising activities in most of the synthetic compounds.
TL;DR: The possibility of using an electronic nose as an alternative method to gas chromatography for the online monitoring and evaluation of efficiency of the n-butanol vapors biofiltration process in a transient state was investigated.
Abstract: Malodorous odors, by definition, are unpleasant, irritating smells being a mixture of volatile chemical compounds that can be sensed at low concentrations. Due to the increasing problem of odor nuisance associated with odor sensations, and thus the need to remove them from the air, deodorization techniques are commonly used. Biofiltration is one of the methods of reducing odorants in the air stream. In the paper, the possibility of using an electronic nose as an alternative method to gas chromatography for the online monitoring and evaluation of efficiency of the n-butanol vapors biofiltration process in a transient state was investigated. Three calibration models were used in the research, i.e., multiple linear regression, principal component regression, and partial least-square regression. The obtained results were compared with the theoretical values.
TL;DR: Both antimicrobial and antiinflammatory results are excellent, among all compounds, sodium acrylate compounds are quite promising against microbial strains and matrix metalloproteins (MMPs).
Abstract: An improved one pot, multi-component synthesis of tri- and tetrasubstituted coumarin–imidazole hybrid has been synthesized at C4 position in good to excellent yield. The reaction was performed under various catalysts and optimization condition results obtained are satisfactory. Wherein, trisubstituted coumarin–imidazole hybrid compounds were converted into phenyl-imidazole acrylates. Further, all the newly synthesized compounds were screened for their antimicrobial activity against Gram-positive Bacillus flexus and Gram-negative Pseudomonas spp. bacterial strains and two strains of fungi studies having Scopulariopsis spp. and Aspergillus terreus organisms. Similarly, antiinflammatory activity of all the compounds was screened against MMP-2 and MMP-9. Both antimicrobial and antiinflammatory results are excellent, among all compounds, sodium acrylate compounds are quite promising against microbial strains and matrix metalloproteins (MMPs). All the isolated compounds were characterized by IR, NMR, and mass spectral analysis.
TL;DR: In this article, the shape of the titration curve indicates that the ion exchange reaction of interlayer K+ to H+ proceeds at pH 7.5-8.5 at a rate as high as 5%min−1.
Abstract: The K2La2Ti3O10 layered oxide was synthesized by high-temperature technique. Ion exchange properties of K2La2Ti3O10·H2O were investigated by continuous potentiometric titration of its suspension in KOH with HCl. The shape of the titration curve indicates that the ion-exchange reaction of interlayer K+ to H+ proceeds at pH 7.5–8.5 at the rate as high as 5% min−1. Samples obtained during the titration experiment at pH 9.8, 4.8, and 1.4 were examined by XRD, TG, ICP-AES, and SEM–EDX. Protonation already occurs at pH > 9.8, while at pH 4.8 a substitution degree of 76% is observed. K2La2Ti3O10 was found to be unstable against K+ leaching, which results in irreversible ion-exchange even when the sample is washed with distilled water. The protonation of the layered oxide significantly suppresses its photocatalytic activity in the reaction of hydrogen production from aqueous isopropanol solution, which correlates with the decreasing amount of intercalated water.
TL;DR: Chalcones and their pyrazine analogs synthesized by Claisen-Schmidt condensation were tested for inhibition of aldose reductase, which is the key enzyme in the development of secondary diabetic complications as discussed by the authors.
Abstract: Chalcones and their pyrazine analogs synthesized by Claisen–Schmidt condensation were tested for inhibition of aldose reductase, which is the key enzyme in the development of secondary diabetic complications. The most active compounds exerted IC50 values within the micromolar scale, and their interactions with the enzyme were described in a molecular docking study. Antioxidant activity of several representative compounds was explored in DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, revealing significant scavenging for 4-hydroxy-substituted derivatives endowed with electron-donating methoxy substituent in position 3 of the ring B. To conclude, the novel chalcones hydroxylated and methoxylated in the B-ring and their pyrazine analogs exhibited significant aldose reductase inhibition activity, albeit lower in comparison with the reference epalrestat. Medium antioxidant activity (not exceeding the antioxidant efficacy of the standard Trolox) was shown by the representative compounds tested.
TL;DR: A number of asymmetrical thioethers combining sterically hindered catechol moiety and different groups (polar, non-polar or redox active) at sulfur atom have been synthesized as discussed by the authors.
Abstract: A number of asymmetrical thioethers combining sterically hindered catechol moiety and different groups (polar, non-polar, or redox active) at sulfur atom have been synthesized. Redox transformations of sulfides were studied by cyclic voltammetry. The electrooxidation of thioethers at the first stage leads to the formation of o-benzoquinones. The presence of a redox-active thioether linker and additional phenolic fragment favors to an extension of the range of redox properties for such functionalized catechols. The introduction of the thioether fragment into catechol ring affects not only the electrochemical behavior of the compounds, but also the antioxidant activity. The antioxidant activities of the compounds were evaluated using 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH) assay, the oxidative damage of the DNA, the reaction of 2,2′-azobis(2-amidinopropane dihydrochloride) (AAPH)-induced glutathione depletion, and the process of lipid peroxidation of rat liver (Wistar) homogenates in vitro. The compounds have greater antiradical effect than 3,5-di-tert-butylcatechol (CatH2) in DPPH assay. In the course of the AAPH-induced oxidative DNA damage, all tested compounds exhibit inhibitory activity unlike CatH2. Among the compounds under investigation, three catechol thioethers reveal mostly antioxidant properties. Several compounds with polar groups possess dual anti/prooxidant activity. The thiolation of catechol ring can change properties of target thiothers by a variation of different organic fragments at sulfur atom.
TL;DR: In this paper, the synthesis and determination of antimycobacterial activity and acid dissociation constants of polyfunctionalized 3-[2-(pyrrolidin-1-yl)thiazole-5-carbonyl]-2H-chromen-2-one derivatives, containing thiazole, coumarin, and pyrrolidine octahydropyrrolo[3,4-c]pyrrole moieties were reported.
Abstract: This study reports on synthesis and determination of antimycobacterial activity and acid dissociation constants of polyfunctionalized 3-[2-(pyrrolidin-1-yl)thiazole-5-carbonyl]-2H-chromen-2-one derivatives, containing thiazole, coumarin, and pyrrolidine octahydropyrrolo[3,4-c]pyrrole moieties. The products were synthesized by a cyclization reaction of 5,5-diphenylpyrrolidine N-aroylthioureas or methyl 5-substituted 4,6-dioxo-3,3-diphenyloctahydropyrrolo[3,4-c]pyrrole-1-carboxylate N-aroylthioureas and 3-(bromoacetyl)coumarin with good to excellent yield (81–97%). The compounds exhibited antimycobacterial activity against the M. tuberculosis H37Rv strain with minimum inhibitory concentration values in the range of 31.25–125 μg/cm3. Acid dissociation constants of the compounds were determined using data which were obtained using a potentiometric titration method in 50% (v/v) dimethyl sulfoxide–water hydroorganic solvent at 25 ± 0.1 °C, at an ionic background of 0.1 mol/dm3 of NaCl. Acid dissociation constants were calculated using the HYPERQUAD computer program. The acid dissociation constants obtained might be associated with SH, OH, and two NH groups, which were formed by the protonation of thiazole and pyrrolidine rings.
TL;DR: In this paper, the authors report the underlying mechanism of the photosensitized dimerization process in the triplet state and demonstrate that this is a stepwise reaction, traversing a long-lived triplet biradical intermediate, which is characterized as a Frenkel exciton with very small charge transfer character.
Abstract: Cyclobutane thymine dimerization is the most prominent DNA photoinduced damage. While the ultrafast mechanism that proceeds in the singlet manifold is nowadays well established, the triplet-state pathway is not completely understood. Here we report the underlying mechanism of the photosensitized dimerization process in the triplet state. Quantum chemical calculations, combined with wavefunction analysis, and nonadiabatic molecular dynamics simulations demonstrate that this is a stepwise reaction, traversing a long-lived triplet biradical intermediate, which is characterized as a Frenkel exciton with very small charge-transfer character. The low yield of the reaction is regulated by two factors: (i) a relatively large energy barrier that needs to be overcome to form the exciton intermediate, and (ii) a bifurcation of the ground-state potential-energy surface that mostly leads back to the Franck–Condon region because dimerization requires a very restricted combination of coordinates and velocities at the event of non-radiative decay to the ground state.
TL;DR: In this paper, the interaction between human serum albumin (HSA) and haloperidol (HPD) was studied by fluorescence and absorption spectroscopy and molecular modeling under physiological conditions.
Abstract: The interaction between human serum albumin (HSA) and haloperidol (HPD) was studied by fluorescence and absorption spectroscopy and molecular modeling under physiological conditions. Fluorescence spectroscopic data showed that the fluorescence quenching of HSA was a result of the formation of the HPD–HSA complex. Spectroscopic analysis of the emission quenching at different temperatures revealed that the quenching mechanism of human serum albumin by haloperidol shows a dynamic quenching. The binding constant (K) and the binding sites (n) between haloperidol and HSA were estimated to be 7.94 × 103 dm3 mol−1 and 1.12 at 298 K. The results of thermodynamic parameters, ΔH (− 89.56 kJ mol−1), ΔS (225.94 J mol−1 K−1) and ΔG (− 15.69 kJ mol−1), indicated that the binding process was spontaneous and the van der Waals interactions and hydrogen bonds were the main forces to stabilize the complex. The distance between the donor (HSA) and acceptor (HPD) molecules was obtained according to Forster energy transfer. The effects of metal ions (Ca2+, Mg2+, Cu2+, and Fe3+) on the binding constant of the haloperidol–HSA complex were also investigated. Finally, the binding of haloperidol to HSA was modeled using the molecular docking method. Molecular docking results were in agreement with the experimental conclusions of the thermodynamic parameters.
TL;DR: Three-component reactions of oxindole derivatives, thiosemicarbazide with dialkyl acetylenedicarboxylate (or maleimide) led to novel indole-hydrazono thiazolidinones in high-to-excellent yields, which are assumed to be used as effective antioxidant and antibacterial agents.
Abstract: Three-component reactions of oxindole derivatives, thiosemicarbazide with dialkyl acetylenedicarboxylate (or maleimide) led to novel indole-hydrazono thiazolidinones in high-to-excellent yields. The antioxidant activities of the synthesized compounds were studied by 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay. Among the products, those with amide moiety exhibited better antioxidant activities than other ester derivatives of indole-hydrazono thiazolidinones. Minimum bactericidal concentration (MBC) was evaluated against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) at different concentrations. However, the MBC values for compounds with amide group in their skeleton exhibited higher antibacterial activity than compounds with ester group. Therefore, it is assumed that these compounds could be used as effective antioxidant and antibacterial agents.
TL;DR: An analytical method for rapid and simultaneous quantitative determination of benzene, toluene, and xylenes in complex hydrocarbon mixtures has been proposed in this article, which consists of obtaining infrared absorption data by attenuated total reflectance Fourier transform infrared spectrometric method in the fingerprint region.
Abstract: An analytical method for rapid and simultaneous quantitative determination of benzene, toluene, and xylenes in complex hydrocarbon mixtures has been proposed. The method consists of obtaining infrared absorption data by attenuated total reflectance Fourier transform infrared spectrometric method in the fingerprint region (630–1000 cm−1). The spectroscopic data were treated by partial least squares and least squares support vector machine (LS-SVM) methods. The LS-SVM results were obtained using radial basis function and parameter optimization was performed using the simplex method. Root mean squares of cross-validation (RMSECV) values of 0.34 for benzene, 1.85 for toluene, and 1.24 for xylenes using PLS algorithm and RMSECV values of 0.37 for benzene, 1.34 for toluene, and 1.1 for xylenes using LS-SVM algorithm were obtained.
TL;DR: In this article, a simple and facile synthesis of pyrazolyl/isoxazolyl 1,3,4-oxadiazole derivatives from the synthetic intermediates of carboxylates adopting conventional and ultrasound irradiation methods was described.
Abstract: This study aimed at describing a simple and facile synthesis of pyrazolyl/isoxazolyl 1,3,4-oxadiazole derivatives from the synthetic intermediates pyrazolyl/isoxazolyl carboxylates adopting conventional and ultrasound irradiation methods. In fact ultrasound-promoted synthesis led to the formation of title compounds in higher yields and in shorter reaction times when compared with conventional methods. All the compounds were characterized by IR, 1H NMR, 13C NMR, and mass spectra. The synthesized compounds were evaluated for their antioxidant and anti-inflammatory activities. The bioassay results indicated that some title compounds were found to be more potent than standard drugs. Amongst all the tested compounds furanyl/pyridinyl linked pyrazolyl/isoxazolyl methoxyphenylsulfonylmethyloxadiazoles were identified as potential antioxidant and anti-inflammatory agents.
TL;DR: Applying density functional theory, a simple computational method is developed for the prediction of the reactivity of aryl/alkyl-substituted tetrazines in inverse electron demand Diels–Alder reactions.
Abstract: The tetrazine ligation is one of the fastest bioorthogonal ligations and plays a pivotal role in time-critical in vitro and in vivo applications. However, prediction of the reactivity of tetrazines in inverse electron demand Diels–Alder-initiated ligation reactions is not straight-forward. Commonly used tools such as frontier molecular orbital theory only give qualitative and often even wrong results. Applying density functional theory, we have been able to develop a simple computational method for the prediction of the reactivity of aryl/alkyl-substituted tetrazines in inverse electron demand Diels–Alder reactions.
TL;DR: In this article, a 5E-principle for effective communication of chemists with the general public is proposed, which answers the questions that chemistry and chemists have faced in the last few decades in connection with communication with the public.
Abstract: The goal of this article is to introduce a different approach to reducing chemophobia. Analysis of the current public image of chemistry, especially the consequences of prevailing chemophobia, can form a basis for changing this negative and dangerous situation for chemistry. Thanks to its unique analytical problem-solving process, analytical chemistry can play an important role in the strategy to reduce chemophobia. The core part of the article describes a newly designed 5E-principle for effective communication. We are convinced that this principle exactly answers the questions that chemistry and chemists have faced in the last few decades in connection with communication with the general public. Three case studies illustrate the application of the proposed 5E-principle for enhancing anti-chemophobic communication of chemists with laymen.
TL;DR: In this article, an efficient and entirely green protocol for preparation of 1-(amido/amino)alkyl-2-naphthols via one-pot multi-component reaction of an aldehyde, 2-Naphthol or phenol and amides or amines using activated Fuller's earth as a heterogeneous catalyst under the solvent-free condition is described.
Abstract: An efficient and entirely green protocol for preparation of 1-(amido/amino)alkyl-2-naphthols via one-pot multi-component reaction of an aldehyde, 2-naphthol or phenol and amides or amines using activated Fuller’s earth as a heterogeneous catalyst under the solvent-free condition is described. This catalyst provides several advantages such as low-cost, stability, reusability, and excellent yields. High catalytic activity and ease of recovery are additional eco-friendly attributes of this catalytic system.