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Keywords = pyrazolonates

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19 pages, 4823 KB  
Article
From Bench to Bioactivity: An Integrated Medicinal Development Based on Kinetic and Simulation Assessment of Pyrazolone-Oxadiazole Coupled Benzamide as Promising Inhibitors of Diabetes Mellitus
by Manal M. Khowdiary and Shifa Felemban
Pharmaceuticals 2025, 18(11), 1595; https://doi.org/10.3390/ph18111595 - 22 Oct 2025
Viewed by 196
Abstract
Background: In this research work, novel pyrazolone-derived oxadiazole-based benzamide derivatives (1–10) were synthesized through unique and facile synthetic routes. Introduction: These scaffolds were designed to be therapeutically more effective and have fewer side effects. Methods: To confirm the structure of analogs [...] Read more.
Background: In this research work, novel pyrazolone-derived oxadiazole-based benzamide derivatives (1–10) were synthesized through unique and facile synthetic routes. Introduction: These scaffolds were designed to be therapeutically more effective and have fewer side effects. Methods: To confirm the structure of analogs in detail, we employed 1HNMR, 13CNMR, and HREI-MS spectroscopy. The potential of all derivatives was tested by screening them against alpha-amylase and alpha-glucosidase in comparison with reference anti-diabetic drug acarbose (4.50 ± 0.20 µM and 4.90 ± 0.30 µM). Results & Discussion: Among all tested analogs and standard drugs, derivative 3 proved to be the most promising candidate. It exhibited the most powerful inhibitory effect (IC50 = 3.20 ± 0.20 µM and 3.60 ± 0.10 µM). To further investigate its activity, the experimental results were supported by in silico investigations. Molecular docking demonstrated strong and viable interactions between enzymes and the most potent compound. DFT calculations validated the electronic configuration, stability, and reactivity of lead molecules. Furthermore, the ADMET profile predicted the favorable drug likeness properties and low toxicity. The results of docking were further confirmed via molecular dynamics analysis, whereas the pharmacophore model of analog 3 supports the formation of a stable hydrogen bond network of derivatives with the receptor site of the enzyme. Conclusions: Collectively in silico and in vitro results underscore the therapeutic potential of these derivatives for the effective treatment of diabetes in the future. Full article
(This article belongs to the Section Medicinal Chemistry)
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11 pages, 1278 KB  
Article
Investigation of Low-Toxicity Azoic Direct Dyes Synthesized from 4,4′-Diaminobenzanilide
by Maria Elena Radulescu-Grad, Simona Popa, Giannin Mosoarca and Vasile Daniel Gherman
Processes 2025, 13(8), 2505; https://doi.org/10.3390/pr13082505 - 8 Aug 2025
Viewed by 436
Abstract
In this paper, a toxicological investigation was carried out on a series of azoic direct dyes generally with an affinity for cellulosic fibers, presenting symmetrical and asymmetrical structures having as a central component a non-carcinogenic, mutagenic, or teratogenic and accessible precursor potential substitute [...] Read more.
In this paper, a toxicological investigation was carried out on a series of azoic direct dyes generally with an affinity for cellulosic fibers, presenting symmetrical and asymmetrical structures having as a central component a non-carcinogenic, mutagenic, or teratogenic and accessible precursor potential substitute for benzidine, namely 4,4′-diaminobenzanilide, and, as coupling components, 2-hydroxybenzoic acid, 2-hydroxy-3,6-naphthalenesulfonic acid, 2-amino-8-hydroxynaphthalene-6-sulfonic acid, 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid, 1-(4′-sulfophenyl)-3-methyl-5-pyrazolone, and 2-hydroxy-6-naphthalenesulfonic acid, respectively. For the purpose of their safe use, this study shows the results regarding the toxicity of the above-mentioned dyes, obtained through biological tests on colonies of Hydractinia echinata (H. echinata). The toxicity tests were performed on heterotrophic bacteria cultures obtained from the Bega River. The minimum toxic concentration was monitored using the dilutions 0.6 g/L, 24 g/L, and 48 g/L, obtained by dilution of a stock solution of 60 g/L. The symmetric dye with the coupling component 2-hydroxybenzoic acid presents the highest degree of toxicity, the lowest being shown by dyes with symmetric and asymmetric structures with the following coupling components: 2-amino-8-hydroxynaphthalene-6-sulfonic acid, 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid, 1-(4′-sulfophenyl)-3-methyl-5-pyrazolone, and 2-hydroxy-6-naphthalenesulfonic acid. Full article
(This article belongs to the Section Biological Processes and Systems)
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28 pages, 5314 KB  
Article
Environmental Cyanide Pollution from Artisanal Gold Mining in Burkina Faso: Human Exposure Risk Analysis Based on a Conceptual Site Model
by Edmond N’Bagassi Kohio, Seyram Kossi Sossou, Hela Karoui and Hamma Yacouba
Int. J. Environ. Res. Public Health 2025, 22(7), 1125; https://doi.org/10.3390/ijerph22071125 - 16 Jul 2025
Cited by 1 | Viewed by 1518
Abstract
Artisanal and small-scale gold mining (ASGM) in Burkina Faso increasingly relies on cyanide, intensifying concerns about environmental contamination and human exposure. This study assessed free cyanide levels in water and soil across three ASGM sites—Zougnazagmiline, Guido, and Galgouli. Water samples (surface and groundwater) [...] Read more.
Artisanal and small-scale gold mining (ASGM) in Burkina Faso increasingly relies on cyanide, intensifying concerns about environmental contamination and human exposure. This study assessed free cyanide levels in water and soil across three ASGM sites—Zougnazagmiline, Guido, and Galgouli. Water samples (surface and groundwater) and topsoil (0–20 cm) were analyzed using the pyridine–pyrazolone method. Data were statistically and spatially processed using SPSS version 29.0 and the Google Earth Engine in conjunction with QGIS version 3.34, respectively. A site conceptual model (SCM) was also developed, based on the literature review, field observations, and validation by multidisciplinary experts in public health, toxicology, ecotoxicology, environmental engineering, and the mining sector, through a semi-structured survey. The results showed that 9.26% of the water samples exceeded the WHO guideline (0.07 mg/L), with peaks of 1.084 mg/L in Guido and 2.42 mg/L in Galgouli. At Zougnazagmiline, the water type differences were significant (F = 64.13; p < 0.001), unlike the other sites. In the soil, 29.36% of the samples exceeded 0.5 mg/kg, with concentrations reaching 9.79 mg/kg in Galgouli. A spatial analysis revealed pollution concentrated near the mining areas but spreading to residential and agricultural zones. The validated SCM integrates pollution sources, transport mechanisms, exposure routes, and vulnerable populations, offering a structured tool for environmental monitoring and health risk assessment in cyanide-impacted mining regions. Full article
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13 pages, 3616 KB  
Article
Synthesis, Structure, and Luminescence Properties of Zinc(II) Complex with a Spacer-Armed Tetradentate N2O2-Donor Schiff Base
by Alexey Gusev, Elena Braga, Kirill Mamontov, Mikhail Kiskin and Wolfgang Linert
Inorganics 2025, 13(5), 173; https://doi.org/10.3390/inorganics13050173 - 19 May 2025
Viewed by 1108
Abstract
A zinc complex bearing a pyrazolone-based azomethine ligand has been synthesized for blue-emitting organic light-emitting diodes (OLEDs). The azomethine ligand H2L and the complex [ZnL·H2O] were characterized by IR, 1H NMR, XRD, and TGA/DSC techniques. According to a single-crystal [...] Read more.
A zinc complex bearing a pyrazolone-based azomethine ligand has been synthesized for blue-emitting organic light-emitting diodes (OLEDs). The azomethine ligand H2L and the complex [ZnL·H2O] were characterized by IR, 1H NMR, XRD, and TGA/DSC techniques. According to a single-crystal X-ray diffraction analysis, the complex [ZnL·H2O] has a molecular structure. Its solid-state PL maxima appear to be at 416 nm and emit moderate blue emission with a quantum yield (QY) of 2%, with a dehydrated form of the complex showing greater efficiency with a QY of 55.5%. ZnL-based electroluminescent devices for OLED applications were fabricated. The devices exhibit blue emission with brightness up to 5300 Cd/A. Full article
(This article belongs to the Section Coordination Chemistry)
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12 pages, 4625 KB  
Article
Enhanced Circularly Polarized Green Luminescence Metrics from New Enantiopure Binary Tris-Pyrazolonate-Tb3+ Complexes
by Jiaxiang Liu, Yongwen Zhang, Ruijuan Yao, Haitao Ren, Weijie Wang, Haohao Feng, Wentao Li and Zongcheng Miao
Molecules 2024, 29(24), 5887; https://doi.org/10.3390/molecules29245887 - 13 Dec 2024
Cited by 1 | Viewed by 1183
Abstract
Achieving superior circularly polarized luminescence brightness (BCPL) is an important subject and continuous challenge for chiroptical materials. Herein, by applying a binary molecular design for the synthesis of chiral organo-Tb3+ molecules, a novel pair of mononuclear chiral tris-pyrazolate-Tb [...] Read more.
Achieving superior circularly polarized luminescence brightness (BCPL) is an important subject and continuous challenge for chiroptical materials. Herein, by applying a binary molecular design for the synthesis of chiral organo-Tb3+ molecules, a novel pair of mononuclear chiral tris-pyrazolate-Tb3+ enantiomers, [Tb(PMIP)3(R,R-Ph-PyBox)] (2) and [Tb(PMIP)3(S,S-Ph-PyBox)] (5), have been synthesized and characterized. The three 1-phenyl-3-methyl-4-(isobutyryl)-5-pyrazolone (HPMIP) ligands play the role of efficient luminescence sensitizers and strong light-harvesting antennas, while the enantiopure 2,6-bis(4-phenyl-2-oxazolin-2-yl) pyridine ligand (R,R/S,S-Ph-PyBox) is employed as the strong point-chiral inducer. With the proper combination of the HPMIP and Chiral-Ph-PyBox within the Tb3+ enantiomers, strong (PMIP)-centered π-π* electronic absorption (ε263 nm = 38,400–39,500 M−1 cm−1) and brilliant high-purity ligand-sensitized Tb3+-centered green luminescence (ΦPL = 47–48%) were observed. In addition, a clear circularly polarized luminescence (CPL) activity (|glum| = 0.096–0.103) was also observed, resulting in a strong BCPL (610–623 M−1 cm−1) for the two Tb3+ enantiomers from the hypersensitive transitions. Our results offer an effective path to develop high-performance chiroptical organo-Tb3+ luminophores. Full article
(This article belongs to the Special Issue Rare Earth Based Luminescent Materials)
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28 pages, 1639 KB  
Review
Metamizole in the Management of Musculoskeletal Disorders: Current Concept Review
by Naveen Jeyaraman, Filippo Migliorini, Shrideavi Murugan, Swaminathan Ramasubramanian, Sangeetha Balaji, Nicola Maffulli and Madhan Jeyaraman
J. Clin. Med. 2024, 13(16), 4794; https://doi.org/10.3390/jcm13164794 - 14 Aug 2024
Cited by 1 | Viewed by 14473
Abstract
Metamizole, or dipyrone, has been used for decades as a non-narcotic analgesic, providing pain relief from musculoskeletal disorders and antipyretic and antispasmolytic properties. Despite being in use since the 1920s, its mechanism of action still needs to be discovered. Despite causing fewer adverse [...] Read more.
Metamizole, or dipyrone, has been used for decades as a non-narcotic analgesic, providing pain relief from musculoskeletal disorders and antipyretic and antispasmolytic properties. Despite being in use since the 1920s, its mechanism of action still needs to be discovered. Despite causing fewer adverse effects when compared to other analgesics, its harmful effects on the blood and lack of evidence regarding its teratogenicity make the usage of the drug questionable, which has led to it being removed from the drug market of various countries. This narrative review aims to provide a detailed insight into the mechanism of action and efficacy, comparing its effectiveness and safety with other classes of drugs and the safety profile of metamizole. Full article
(This article belongs to the Section Orthopedics)
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14 pages, 3919 KB  
Article
α-Carbonyl Rh-Carbenoid Initiated Cascade Assembly of Diazobarbiturates with Alkylidene Pyrazolones for Synthesis of Spirofuropyrimidines
by Yue Zhang, Yu-Hang Mi, Kuo Wang and Hong-Wu Zhao
Molecules 2024, 29(13), 3178; https://doi.org/10.3390/molecules29133178 - 3 Jul 2024
Viewed by 1666
Abstract
Catalyzed by Rh2(esp)2 (10 mol%) and (±)-BINAP (20 mol%) in DCE at 80 °C, the cascade assembly between diazobarbiturates and alkylidene pyrazolones proceeded readily and produced spiro-furopyrimidines in 38–96% chemical yields. The chemical structure of the prepared spirofuro-pyrimidines was firmly [...] Read more.
Catalyzed by Rh2(esp)2 (10 mol%) and (±)-BINAP (20 mol%) in DCE at 80 °C, the cascade assembly between diazobarbiturates and alkylidene pyrazolones proceeded readily and produced spiro-furopyrimidines in 38–96% chemical yields. The chemical structure of the prepared spirofuro-pyrimidines was firmly confirmed by X-ray diffraction analysis. Full article
(This article belongs to the Special Issue Recent Advances in Transition Metal Catalysis)
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11 pages, 1335 KB  
Article
Synthesis, Characterization and Antimicrobial and Anticancer Evaluations of Some Novel Heteroannulated Difuro[3,2-c:3′,2′-g]Chromenes
by Najla A. Alshaye, Magdy A. Ibrahim and Al-Shimaa Badran
Molecules 2024, 29(10), 2319; https://doi.org/10.3390/molecules29102319 - 15 May 2024
Cited by 1 | Viewed by 1343
Abstract
The goal of this study was directed to synthesize a novel class of annulated compounds containing difuro[3,2-c:3′,2′-g]chromene. Friedländer condensation of o-aminoacetyl derivative 3 was performed with some active methylene ketones, namely, 1,3-cyclohexanediones, pyrazolones, 1,3-thiazolidinones and barbituric acids, furnished [...] Read more.
The goal of this study was directed to synthesize a novel class of annulated compounds containing difuro[3,2-c:3′,2′-g]chromene. Friedländer condensation of o-aminoacetyl derivative 3 was performed with some active methylene ketones, namely, 1,3-cyclohexanediones, pyrazolones, 1,3-thiazolidinones and barbituric acids, furnished furochromenofuroquinolines (4,5), furochromenofuropyrazolopyridines (68), furochromenofurothiazolopyridines (9,10) and furochromenofuropyridopyrimidines (11, 12), respectively. Also, condensation of substrate 3 with 5-amine-3-methyl-1H-pyrazole and 6-amino-1,3-dimethyluracil, as cyclic enamines, resulted in polyfused systems 13 and 14, respectively. In vitro antimicrobial efficiency of the prepared heterocycles against microbial strains exhibited variable inhibition action, where compound 3 was the most effective against all kinds of microorganisms. A significant cytotoxic activity was seen upon the annulation of the starting compound with thiazolopyridine (9 and 10) as well as pyridopyrimidine moieties (11, 12 and 14). The spectroscopic and analytical results were used to infer the structures of the novel synthesized compounds. Full article
(This article belongs to the Section Organic Chemistry)
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16 pages, 5179 KB  
Article
A Rapid and Accurate UHPLC Method for Determination of Monosaccharides in Polysaccharides of Different Sources of Radix Astragali and Its Immune Activity Analysis
by Yali Guo, Lijun Wang, Kaishuang Liu, Meifang Li, Yibao Jin, Lifei Gu, Xie-An Yu, Shuhong Wang, Ping Wang, Bing Wang and Tiejie Wang
Molecules 2024, 29(10), 2287; https://doi.org/10.3390/molecules29102287 - 13 May 2024
Cited by 5 | Viewed by 2331
Abstract
With the escalating demand for Astragalus polysaccharides products developed from Radix Astragali (RA), the necessity for quality control of polysaccharides in RA has become increasingly urgent. In this study, a specific method for the simultaneous determination of seven monosaccharides in polysaccharides extracted from [...] Read more.
With the escalating demand for Astragalus polysaccharides products developed from Radix Astragali (RA), the necessity for quality control of polysaccharides in RA has become increasingly urgent. In this study, a specific method for the simultaneous determination of seven monosaccharides in polysaccharides extracted from Radix Astragali (RA) has been developed and validated using ultra-performance liquid chromatography equipped with an ultraviolet detector (UHPLC-UV) for the first time. The 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatizations were separated on a C18 column (Waters ACQUITYTM, Milfor, MA, USA, 1.8 µm, 2.1 × 100 mm) using gradient elution with a binary system of 5 mm ammonium formate (0.1% formic acid)-acetonitrile for 24 min. Additionally, seven monosaccharides showed good linear relationships (R2, 0.9971–0.9995), adequate precision (RSD < 4.21%), and high recoveries (RSD < 4.70%). The established method was used to analyze 109 batches of RA. Results showed that the Astragalus polysaccharides (APSs) mainly consist of mannose (Man), rhamnose (Rha), glucose (Glu), galactose (Gal), arabinose (Ara), xylose (Xyl); and fucose (Fuc); however, their composition was different among RA samples from different growth patterns, species, growth years, and origins, and the growth mode of RA and the age of wild-simulated RA can be accurately distinguished by principal component analysis (PCA). In addition, the immunological activity of APSs were also evaluated jointly by measurement of the NO release with RAW264.7, with the results showing that APSs have a promoting effect on the release of NO and exhibit a significant correlation with Man, Glu, Xyl, and Fuc contents. Accordingly, the new established monosaccharides analytical method and APS-immune activity determination in this study can provide a reference for quality evaluation and the establishment of quality standards for RA. Full article
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17 pages, 2912 KB  
Article
Applying Machine Learning and Statistical Forecasting Methods for Enhancing Pharmaceutical Sales Predictions
by Konstantinos P. Fourkiotis and Athanasios Tsadiras
Forecasting 2024, 6(1), 170-186; https://doi.org/10.3390/forecast6010010 - 16 Feb 2024
Cited by 16 | Viewed by 12168
Abstract
In today’s evolving global world, the pharmaceutical sector faces an emerging challenge, which is the rapid surge of the global population and the consequent growth in drug production demands. Recognizing this, our study explores the urgent need to strengthen pharmaceutical production capacities, ensuring [...] Read more.
In today’s evolving global world, the pharmaceutical sector faces an emerging challenge, which is the rapid surge of the global population and the consequent growth in drug production demands. Recognizing this, our study explores the urgent need to strengthen pharmaceutical production capacities, ensuring drugs are allocated and stored strategically to meet diverse regional and demographic needs. Summarizing our key findings, our research focuses on the promising area of drug demand forecasting using artificial intelligence (AI) and machine learning (ML) techniques to enhance predictions in the pharmaceutical field. Supplied with a rich dataset from Kaggle spanning 600,000 sales records from a singular pharmacy, our study embarks on a thorough exploration of univariate time series analysis. Here, we pair conventional analytical tools such as ARIMA with advanced methodologies like LSTM neural networks, all with a singular vision: refining the precision of our sales. Venturing deeper, our data underwent categorisation and were segmented into eight clusters premised on the ATC Anatomical Therapeutic Chemical (ATC) Classification System framework. This segmentation unravels the evident influence of seasonality on drug sales. The analysis not only highlights the effectiveness of machine learning models but also illuminates the remarkable success of XGBoost. This algorithm outperformed traditional models, achieving the lowest MAPE values: 17.89% for M01AB (anti-inflammatory and antirheumatic products, non-steroids, acetic acid derivatives, and related substances), 16.92% for M01AE (anti-inflammatory and antirheumatic products, non-steroids, and propionic acid derivatives), 17.98% for N02BA (analgesics, antipyretics, and anilides), and 16.05% for N02BE (analgesics, antipyretics, pyrazolones, and anilides). XGBoost further demonstrated exceptional precision with the lowest MSE scores: 28.8 for M01AB, 1518.56 for N02BE, and 350.84 for N05C (hypnotics and sedatives). Additionally, the Seasonal Naïve model recorded an MSE of 49.19 for M01AE, while the Single Exponential Smoothing model showed an MSE of 7.19 for N05B. These findings underscore the strengths derived from employing a diverse range of approaches within the forecasting series. In summary, our research accentuates the significance of leveraging machine learning techniques to derive valuable insights for pharmaceutical companies. By applying the power of these methods, companies can optimize their production, storage, distribution, and marketing practices. Full article
(This article belongs to the Section Forecasting in Economics and Management)
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5 pages, 1258 KB  
Proceeding Paper
Synthesis and Evaluation of Thiomethyl-Substituted (4Z)-4-[(Pyrazol-4-yl)methylene]pyrazolone as an Optical Chemosensor
by Paola V. Mazón Ayala, Juan Carlos Romero-Benavides and Jorge Heredia-Moya
Chem. Proc. 2023, 14(1), 50; https://doi.org/10.3390/ecsoc-27-16123 - 15 Nov 2023
Viewed by 1233
Abstract
Developing colorimetric devices for detecting chemical species is essential in many fields; nevertheless, developing effective chemosensors for many heavy and transition metal ions remains an important issue. As a result, in recent years, the use of colorimetric sensors for the selective and sensitive [...] Read more.
Developing colorimetric devices for detecting chemical species is essential in many fields; nevertheless, developing effective chemosensors for many heavy and transition metal ions remains an important issue. As a result, in recent years, the use of colorimetric sensors for the selective and sensitive detection of metal ions has grown in popularity. Pyrazolones and their derivatives are heterocyclic compounds that have attracted interest due to their biological and pharmacological features. As a result, they have been used in various areas, including agriculture, medicine, organic synthesis, and analytical chemistry. However, the potential for chemosensing has yet to receive much attention. In this study, thiomethyl-substituted (4Z)-4-[(pyrazol-4-yl)methylene]pyrazolone was synthesized, and its ability to act as an optical chemosensor for several metals was evaluated. According to preliminary results, this molecule could be an optical chemosensor to detect Fe3+, Sn2+, and Al3+. Full article
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17 pages, 3326 KB  
Article
New Sustainable Solvent Extraction Pathways for Rare Earth Metals via Oximes Molecules
by Maria Atanassova, Rositsa Kukeva and Vanya Kurteva
Molecules 2023, 28(22), 7467; https://doi.org/10.3390/molecules28227467 - 7 Nov 2023
Cited by 12 | Viewed by 2651
Abstract
A study on the synergistic extraction of Eu(III) ions with a series of chelating ligands and determination of the process parameters is presented by employing ionic liquids and typical organic diluents. The investigations of the liquid–liquid extraction, commonly applied in the separation science [...] Read more.
A study on the synergistic extraction of Eu(III) ions with a series of chelating ligands and determination of the process parameters is presented by employing ionic liquids and typical organic diluents. The investigations of the liquid–liquid extraction, commonly applied in the separation science of 4f and 5f-ions acidic chelating compounds, 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HP), 4-benzoyl-3-phenyl-5-isoxazolone (HPBI), and 2-thenoyltrifluoroacetone (HTTA) alone and in combination with two synergistic agents, meso-hexamethylpropyleneamine oxime (S2: HM-PAO) and its bis-imine precursor (S1: pre-HM-PAO), are presented. The interaction between the two extractants (acidic/neutral) in deuterochloroform was studied using 1H, 13C, and 1H-1H NOESY experiments. Several conclusions are given highlighting the role of the ionic diluent in complexation processes and selectivity with an employment of the two synergistic agents for various metal s-, p-, d-, and f-cations in the Periodic table, with almost 25 metal ions. The objective was to optimize a system for 4f-ions solvent extraction based on the new oxime molecules with β-diketone/isoxazolone/pyrazolone partnership. As detailed above, slight enhancements of extraction efficiencies were obtained either by using basic synergistic agents such as HM-PAO and/or using pre-HM-PAO. A competitive solvent extraction test of nearly 18 f-ions by various ligands (HTTA, S1, S2, and HPBI) and the two mixtures HTTA−S1 and HTTA−S2 diluted in ILs or organic diluents was also conducted in order to evaluate the switchable diluent impact. Additionally, electron paramagnetic resonance (EPR) spectroscopy was used to study the established chemical species with Cu2+ cations in the obtained organic extracts involving the two synergistic molecules. Full article
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18 pages, 4615 KB  
Article
Diastereoselective Cascade Cyclization of Diazoimides with Alkylidene Pyrazolones for Preparation of Pyrazole-Fused Oxa-Bridged Oxazocines
by Kuo Wang, Yue Zhang, Lu-Yu Cai, Xiu-Qing Song, Chen Wang, Jia-Rui Zhang, Yi-Fan Pan and Hong-Wu Zhao
Molecules 2023, 28(20), 7021; https://doi.org/10.3390/molecules28207021 - 10 Oct 2023
Viewed by 1924
Abstract
Under the catalysis of Rh2(OAc)4 (10 mol%) and binapbisphosphine ligand (±)-L3 (20 mol%) in DCE at 80 °C, the cascade cyclization of diazoimides with alkylidenepyrazolones underwent stereoselectively (dr > 20:1), affording pyrazole-fused oxa-bridged oxazocines in reasonable chemical yields. The [...] Read more.
Under the catalysis of Rh2(OAc)4 (10 mol%) and binapbisphosphine ligand (±)-L3 (20 mol%) in DCE at 80 °C, the cascade cyclization of diazoimides with alkylidenepyrazolones underwent stereoselectively (dr > 20:1), affording pyrazole-fused oxa-bridged oxazocines in reasonable chemical yields. The chemical structure and relative configuration of title products were firmly identified by X-ray diffraction analysis. Full article
(This article belongs to the Section Organic Chemistry)
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36 pages, 6604 KB  
Article
New Azo Dyes-Based Mg Complex Pigments for Optimizing the Anti-Corrosion Efficiency of Zinc-Pigmented Epoxy Ester Organic Coatings
by Miroslav Kohl, Fouzy Alafid, Karolína Boštíková, Marek Bouška, Anna Krejčová, Jan Svoboda, Stanislav Slang, Ludmila Michalíčková, Andréa Kalendová, Radim Hrdina, Ladislav Burgert, Eva Schmidová, Pravin P. Deshpande and Abhijit A. Bhopale
Coatings 2023, 13(7), 1276; https://doi.org/10.3390/coatings13071276 - 20 Jul 2023
Cited by 8 | Viewed by 3294
Abstract
This work addresses the possibilities of using synthesized novel magnesium complex dyes in zinc pigmented organic coatings based on epoxyester resin to reduce the zinc content in these coatings while maintaining or increasing the anticorrosive efficiency of them. The magnesium complexes Mg-Dye-I (C [...] Read more.
This work addresses the possibilities of using synthesized novel magnesium complex dyes in zinc pigmented organic coatings based on epoxyester resin to reduce the zinc content in these coatings while maintaining or increasing the anticorrosive efficiency of them. The magnesium complexes Mg-Dye-I (C34H26MgN8O6), Mg-Dye-II (C26H19MgN3O5), Mg-Dye-III (C17H10MgN2O3), and Mg-Dye-IV (C25H18MgN4O6) with a series of azo carboxylate ligands were prepared from the diazo-coupling reaction of anthranilic acid with 5-methyl-2-phenyl-3-pyrazolone (Dye I; C17H14N4O3), anthranilic acid with naphthol AS-PH (Dye II; C26H21N3O5), anthranilic acid with 2-naphthol (Dye III; C17H12N2O3), and 2-amino-5-nitrophenol with naphthol AS-PH (Dye IV; C25H20N4O6). The synthesized novel magnesium complex dyes were characterized by analytical methods. Model coatings containing these dyes at pigment volume concentrations (PVCs) = 1, 3, 5 and 10% and zinc at a ratio of pigment volume concentration/critical pigment volume concentration (PVC/CPVC) = 0.60 were formulated to study the inhibitory properties of the individual synthesized magnesium complex dyes. Model coatings containing inorganic pigments (MgO and Ca-Mg-HPO4) at PVCs = 1%, 3%, 5% and 10% and zinc at PVC/CPVC = 0.60 were also formulated. The coating pigmented only by zinc at PVC/CPVC = 0.60 was prepared as a standard organic coating. Corrosion resistance was also evaluated by potentiodynamic polarization studies and electrochemical impedance spectroscopy. The properties of organic coatings were also tested using other standardized and derived corrosion tests. In addition, the mechanical properties of the studied organic coatings were determined using standard tests. The aim of the work was to verify the possible synergistic efficiency of novel magnesium complex dyes by improving the mechanical, anti-corrosion, and chemical properties of zinc pigmented organic coatings. Full article
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7 pages, 2204 KB  
Communication
Photoinduced Ring Opening of Methyl 1-Aryl-5-oxo-6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazole-2-carboxylates in the Presence of Diaryl Disulfides
by Nejc Petek and Uroš Grošelj
Molbank 2023, 2023(2), M1670; https://doi.org/10.3390/M1670 - 15 Jun 2023
Viewed by 1642
Abstract
Among the methods used for the synthesis of functionalized heterocyclic compounds, photochemistry has gained immense popularity due to the reactivity of intermediates in photoinduced reactions. In this study, we report on the effect of diaryl disulfides as hydrogen atom transfer catalysts on the [...] Read more.
Among the methods used for the synthesis of functionalized heterocyclic compounds, photochemistry has gained immense popularity due to the reactivity of intermediates in photoinduced reactions. In this study, we report on the effect of diaryl disulfides as hydrogen atom transfer catalysts on the photoinduced transformations of pyrazolo[1,2-a]pyrazolones. After excitation with visible light, these compounds are susceptible to C–N bond cleavage, followed by intermolecular hydrogen atom abstraction. By modifying the reaction conditions, we have developed two novel methods for the synthesis of highly substituted pyrazoles. Full article
(This article belongs to the Collection Heterocycle Reactions)
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