Search Results (206)

We report the synthesis and characterization of the novel pyridinium salts from (E)-2-(pyridin-4-ylmethylene)hydrazine-1-carboximidamide. The pyridinium salts were obtained via the reaction of guanylhydrazone derived from pyridine-4-carbaldehyde with phenacyl bromides. Structural characterization was carried out using IR, ¹H, and ¹³C NMR spectroscopy and mass spectrometry. Full article

Engineering phase-selective gel composites presents a promising route to enhance both CO₂ adsorption and conversion efficiency in photocatalytic systems. In this work, Cu₉S₅/TiO₂ gel composites were synthesized via a hydrazine-hydrate-assisted hydrothermal method, using TiO₂ derived from a microwave-assisted sol–gel process. The resulting materials exhibit a porous gel-derived morphology with highly dispersed Cu₉S₅ nanocrystals, as confirmed by XRD, TEM, and XPS analyses. These structural features promote abundant surface-active sites and interfacial contact, enabling efficient CO₂ adsorption. Among all samples, the optimized 0.36Cu₉S₅/TiO₂ composite achieved a methane production rate of 34 μmol·g⁻¹·h⁻¹, with 64.76% CH₄ selectivity and 88.02% electron-based selectivity, significantly outperforming Cu₉S₈/TiO₂ synthesized without hydrazine hydrate. This enhancement is attributed to the dual role of hydrazine: facilitating phase transformation from Cu₉S₈ to Cu₉S₅ and modulating the interfacial electronic environment to favor CO₂ capture and activation. DFT calculations reveal that Cu₉S₅/TiO₂ effectively lowers the energy barriers of critical intermediates (*COOH, *CO, and *CHO), enhancing both CO₂ adsorption strength and subsequent conversion to methane. This work demonstrates a gel-derived composite strategy that couples efficient CO₂ adsorption with selective photocatalytic reduction, offering new design principles for adsorption–conversion hybrid materials. Full article

Some studies performed in our laboratory on pyrrole and its derivatives pointed towards the enrichment of the evaluations of these promising chemical structures for the potential treatment of neurodegenerative conditions in general and Parkinson’s disease in particular. A classical Paal-Knorr cyclization approach is applied to synthesize the basic hydrazine used for the formation of the designed series of hydrazones (15a–15g). The potential neurotoxic and neuroprotective effects of the newly synthesized derivatives were investigated in vitro using different models of induced oxidative stress at three subcellular levels (rat brain synaptosomes, mitochondria, and microsomes). The results identified as the least neurotoxic molecules, 15a, 15d, and 15f applied at a concentration of 100 µM to the isolated fractions. In addition, the highest statistically significant neuroprotection was observed for 15a and 15d at a concentration of 100 µM using three different injury models on subcellular fractions, including 6-hydroxydopamine in rat brain synaptosomes, tert-butyl hydroperoxide in brain mitochondria, and non-enzyme-induced lipid peroxidation in brain microsomes. The hMAOA/MAOB inhibitory activity of the new compounds was studied at a concentration of 1 µM. The lack of a statistically significant hMAOA inhibitory effect was observed for all tested compounds, except for 15f, which showed 40% inhibitory activity. The most prominent statistically significant hMAOB inhibitory effect was determined for 15a, 15d, and 15f, comparable to that of selegiline. The corresponding selectivity index defined 15f as a non-selective MAO inhibitor and all other new hydrazones as selective hMAOB inhibitors, with 15d indicating the highest selectivity index of >471. The most active and least toxic representative (15d) was evaluated in vivo on Rotenone based model of Parkinson’s disease. The results revealed no microscopically visible alterations in the ganglion and glial cells in the animals treated with rotenone in combination with 15d. Full article

Hydrazine, a highly toxic and reactive compound widely used as rocket fuel, poses significant environmental and health risks, particularly in long-term space missions. This study investigates the cometabolic capacity of Chlorella vulgaris and seven extremophilic Bacillus spp. strains—isolated from the arid Dead Sea region—to tolerate and degrade hydrazine at concentrations up to 25 ppm. The microalga C. vulgaris reduced hydrazine levels by 81% within 24 h at 20 ppm, while the Bacillus isolates achieved an average reduction of 45% over 120 h. Identified strains included B. licheniformis, B. cereus, and B. atrophaeus. Co-culture experiments demonstrated that C. vulgaris and B. cereus (isolate ISO-36) stably coexisted without antagonistic effects, suggesting a synergistic detoxification interaction. Flow cytometry revealed that most bacteria transitioned into spores under stress, highlighting a survival adaptation. Titanium, representing a biocompatible material common in aerospace hardware, did not inhibit microbial growth or hydrazine degradation. These findings underscore the potential of Dead Sea-derived microbial consortia for cometabolic hydrazine detoxification and support the feasibility of converting spacecraft components into functional photobioreactors. This approach offers dual-use benefits for space missions and industrial wastewater treatment. Future studies should investigate degradation pathways, stress resilience, and bioreactor scale-up. Full article

In this study, the design and synthesis of a novel series of cinnamic acid and 1,2,4-triazole hybrids were reported, aiming to enhance antioxidant and lipoxygenase inhibitory activities through pharmacophore combination. Cinnamic acid derivatives and 1,2,4-triazoles exhibit a broad spectrum of biological activities; therefore, by synthesizing hybrid molecules, we would like to exploit the beneficial characteristics of each scaffold. The general synthetic procedure comprises three synthetic steps, starting from the reaction of appropriate substituted cinnamic acid with hydrazine monohydrate in acetonitrile with cyclohexane and resulting in the formation of hydrazides. Consequently, the hydrazides reacted with phenylisothiocyanate under microwave irradiation conditions. Then, cyclization proceeded to the 1,2,4-triazole after the addition of NaOH solution and microwave irradiation. All the synthesized derivatives have been studied for their ability (a) to interact with the free radical DPPH, (b) inhibit lipid peroxidation induced by AAPH, and (c) inhibit soybean lipoxygenase. The synthesized derivatives have shown significant antioxidant activity and have been proved to be very good lipoxygenase inhibitors. Compounds 4b and 4g (IC₅₀ = 4.5 μM) are the most potent within the series followed by compound 6a (IC₅₀ = 5.0 μM). All the synthesized derivatives have been subjected to docking studies related to soybean lipoxygenase. Compound 4g exhibited a docking score of −9.2 kcal/mol and formed hydrophobic interactions with Val126, Tyr525, Lys526, Arg533, and Trp772, as well as a π−cation interaction with Lys526. Full article

Two pyrene derivatives, substituted at position 1 with isoxazole or NH-pyrazole, were synthesized in 85–87% yield starting from 1-acetylpyrene and via the cyclocondensation reaction of a β-enaminone intermediate with hydroxylamine or hydrazine. The photophysics of the two 5-(1-pyrenyl)-1,2-azoles were explored, revealing that only the isoxazole derivative exhibits good emission properties (ϕ_F ≥ 74%) but without solvatofluorochromism behavior. However, both probes exhibited noticeable photophysics in the aggregated state (in the presence of H₂O and/or in the solid state) and through acid–base interactions (using TFA and TBACN), leveraging the basic and acidic character of the analyzed 1,2-azoles, which was also investigated by ¹H NMR spectroscopy. Therefore, the selective incorporation of N-heteroaromatic units into the pyrene scaffold effectively modulates the photophysics and environmental sensitivity of the corresponding probes. Full article

Bacterial infections, particularly those caused by multidrug-resistant strains, remain a significant global public health challenge. The growing resistance to traditional antibiotics highlights the urgent need for novel antibacterial strategies. Herein, we successfully synthesized three types of nitrogen-doped carbon dots (tBuCz-CDs, HAH-CDs, and EC-CDs) via hydrothermal method using tert-butyl carbazate, hydroxyacetic acid hydrazide, and ethyl carbazate as precursors. tBuCz-CDs, HAH-CDs, and EC-CDs exhibited potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), with minimum inhibitory concentrations (MICs) of 100, 100, and 150 µg/mL, respectively. Their antibacterial effect on MRSA was comparable to that of the widely used antibiotic vancomycin hydrochloride, as shown by the zone of inhibition assay. Furthermore, the carbon dots exhibited low cytotoxicity and hemolytic activity showing their excellent biocompatibility both in vitro and in vivo. They also significantly promoted wound healing compared to untreated controls. Notably, the serial passaging of MRSA exposed to these carbon dots did not result in the bacterial resistance. Mechanistic studies revealed that the carbon dots exerted antibacterial effects through multiple mechanisms, including the disruption of bacterial membranes, inhibition and eradication of biofilm formation, generation of reactive oxygen species, and DNA damage. This work highlights the potential of nitrogen-doped CDs as a promising material for combating drug-resistant bacterial infections and underscores their potential for further biomedical development. Full article

In rocketry today, conventional hypergolic propellant combinations typically use hydrazine-derived fuels and oxidizers based on nitrogen tetroxide. Due to their high toxicity and consequently expensive handling, safer alternatives, so-called “green hypergolics”, are currently being developed. The ionic liquid-based fuels [EMIM][SCN], HIP_11 and HIM_30, paired with highly concentrated hydrogen peroxide as an oxidizer, are three candidates for such green hypergolics, which are currently under research at the German Aerospace Center (DLR). These combinations have been shown to exhibit reliable hypergolic ignition. For a better understanding of the reaction process and to assess the risks in working with these propellants, it is desirable to determine their combustion products. A test setup was designed to extract the gaseous combustion products from hypergolic drop tests. The gas samples were analyzed using Fourier-transform infrared spectroscopy and the gaseous combustion products were determined from the infrared spectra. Additional tests with varied oxidizer concentration or alternative fuels were conducted to further investigate detailed aspects of the findings. It was concluded that [EMIM][SCN], HIP_11 and HIM_30 produce very similar sets of combustion products with hydrogen peroxide, including water vapor, carbon dioxide, carbon monoxide, hydrogen cyanide and sulfur dioxide. Finally, the combustion products were compared to the substances produced when thermally decomposing the fuels. This confirmed that the previously detected substances were caused by a reaction between hydrogen peroxide and the fuels, rather than by their thermal decomposition due to heating. Full article

Free radicals and inflammation have pivotal role in various degenerative diseases like cancer, rheumatoid arthritis, diabetes, cardiovascular and neurodegenerative disorders. Pyrazoles possess a wide range of biological activities such as antifungal, antituberculosis, antimicrobial, antiviral, anti-inflammatory, anti-convulsant, anticancer etc. In this present study a series of dibenzalacetones and the corresponding pyrazole hybrids were designed through bioisosterism, synthesized and biologically evaluated to highlight the importance of the extended conjugated system and substitution to the anti-inflammatory and antioxidant activity. The synthesis of dibenzalacetones was achieved via Claisen-Schmidt reaction. The dihydro-pyrazoles were synthesized from the substituted dibenzacetones and phenylhydrazines, hydrazine and semicarbazide under microwave irradiation optimizing reaction conditions. The synthesized compounds were spectroscopically characterized and evaluated for their anti-lipid peroxidation (AAPH) activity, their interaction with the free radical DPPH and the inhibition of soybean LOX. The novel derivatives were studied in terms of their physicochemical properties. Many of the dihydro-pyrazoles showed potent antioxidant properties and significant inhibition of soybean lipoxygenase as a result of their physicochemical features. Compounds 4a and 4b presented the most potent anti-lipid peroxidation abilities (98% and 97%), whereas compounds 2d and 2e have proved to be the most potent lipoxygenase inhibitors with IC₅₀ values 2.5 μM and 0.35 μM. Moreover, docking studies with soybean lipoxygenase highlight the interactions of the novel derivatives with the enzyme. Full article

Introduction: Inhibiting cyclooxygenase-2 (COX-2) is a potential strategy in inflammation therapy. Thus, developing COX-2 inhibitors plays a pivotal role in efficient inflammation treatment. This study discloses the synthesis of new heterocyclic compounds incorporating pyridine, pyran, and/or pyrazole moieties as COX-2 inhibitors. Methods: In this study, the Claisen–Schmidt reaction of 1-(5-hydroxy-1,3-diphenyl-1H-pyrazol-4-yl)ethan-1-one 1 and p-methoxybenzaldehyde in ethanol containing aqueous sodium hydroxide (10%) led to the formation of 1-(5-hydroxy-1,3-diphenyl-1H-pyrazol-4-yl)-3-(4-methoxyphenyl)prop-2-en-1-one) 2. The latter compound was allowed to react as a key precursor with various nucleophiles such as ethyl cyanoacetate, malononitrile, cyclohexanone, ethyl acetoacetate, hydrazine, cyano acid hydrazide, hydrazide, and/or thiosemicarbazide to yield new heterocyclic derivatives comprising pyridine, pyran, and/or pyrazole moieties 3–15, according to the Michael addition reaction. The newly synthesized compounds were depicted using spectroscopic techniques such as IR, ¹H-NMR, ¹³C-NMR, and MS. Moreover, their anti-inflammatory efficiency was in vitro evaluated by means of protein denaturation inhibition and cell membrane protection assay. Results: The results of 2^−ΔΔct values of COX-2 expression for compounds 6, 11, 12, and 13 were 6.6, 2.9, 25.8, and 10.1, respectively. Therefore, compound 12, followed by 13, 11, and 6, showed potent anti-inflammatory properties by in vitro evaluation. Further, an in silico molecular docking study was performed on the best-docked compounds and reference drug (Diclofenac) to investigate their binding affinities against the active site of the target enzyme. The obtained results from the in silico study aligned with the biological evaluation. Conclusions: The studies open new doors for designing new heterocycles containing pyridine, pyran, and/or pyrazole moieties as potent anti-inflammatory agents. Full article

Copper ions (Cu²⁺) are the third most essential transition metal ions critical to human health. Rapid detection of Cu²⁺ in water and biological fluids is of significant importance. In this study, we develop a sensitive multi-channel paper microfluidic device integrated with a 3D-printed smartphone-based colorimetric reader for the rapid detection of Cu²⁺. A novel rhodamine derivative, 1-(N,N-dichloromethine) amino-4-rhodamine B hydrazine-benzimide (RBCl), exhibiting high selectivity and sensitivity to Cu²⁺, was synthesized and applied as the detection reagent. The interaction mechanism between RBCl and Cu²⁺ was investigated, revealing a structural transition from a colorless spirolactam (closed-ring) to an open-ring amide structure, resulting in a pink color upon Cu²⁺ binding. A multi-channel paper microfluidic device with eight detection zones was fabricated, enabling the simultaneous analysis of eight samples. To enhance portability and quantification, a 3D-printed smartphone colorimetric reader was integrated, providing a rapid and efficient detection platform. The system achieved highly specific Cu²⁺ detection within 2 min, with a detection limit as low as 1.51 ng/mL, meeting water monitoring standards in most countries. Excellent recoveries were demonstrated in real samples, including tap water, river water, blood serum, and urine diluent. This integrated paper microfluidic system is highly sensitive and specific, offering a promising solution for water quality monitoring and health assessment through its rapid sample-to-answer capability. Full article

The selective inhibition of key enzymes, such as carbonic anhydrases (CAs IX and XII), which are overexpressed in cancer tissues, has emerged as a promising strategy in cancer research. However, a multitarget approach is often preferred to achieve enhanced therapeutic outcomes. In this study, aryl sulfonamides were conjugated with a thiosemicarbazone moiety to enable dual functionality: the inhibition of CAs and the chelation of metal cations. Several structural factors were systematically modified, including the position of the sulfonamido group, the length of the linker, the nature of the aromatic residue, and the type of substituents. Tumor-associated CAs IX and XII inhibition was evaluated using the stopped-flow CO₂ hydrase assay, and the inhibition constants (K_i) were determined. The most promising compounds were further analyzed through molecular docking simulations. Metal chelation capabilities were evaluated using UV–Vis spectroscopy, while antiproliferative activities were measured using the sulforhodamine B (SBR) assay. Additionally, holotomographic 3D microscopy was employed to investigate the mechanisms of cell death. Sulfonamido-derived Schiff bases were synthesized through a three-step procedure that did not require column chromatography purification: (1) isothiocyanation of amino-sulfonamides, (2) nucleophilic addition of hydrazine, and (3) acid-promoted condensation with different aldehydes (benzaldehydes or pyridine-2-carboxaldehyde). The synthesized compounds exhibited inhibition of CAs in the low nanomolar to submicromolar range, with selectivity largely influenced by structural features. Notably, the m-sulfonamide derivative 5b, bearing a pyridin-2-yl residue, demonstrated potent and selective inhibition of CA IX (K_i = 4.9 nM) and XII (K_i = 5.6 nM). Additionally, it efficiently chelated Fe²⁺, Fe³⁺, and Cu²⁺ and showed promising antiproliferative activity (GI₅₀ 4.5–10 µM). Mechanistic studies revealed that apoptosis was involved in its mode of action. Therefore, the synergistic integration of sulfonamides and thiosemicarbazones represents an effective strategy for the development of multimodal anticancer agents. Full article

Monoamine oxidase B (MAO-B) is a key enzyme in the mitochondrial outer membrane, pivotal for the oxidative deamination of biogenic amines. Its overexpression has been implicated in the pathogenesis of several cancers, including glioblastoma and colorectal, lung, renal, and bladder cancers, primarily through the increased production of reactive oxygen species (ROS). Inhibition of MAO-B impedes cell proliferation, making it a potential therapeutic target. Various monoamine oxidase B inhibitors have shown promise in inhibiting tumor growth and inducing apoptosis across different cancer types. In this review, we investigate MAO-B network biology, which highlighted glycolysis pathways as notable links between MAO-B and cancer. Further molecular modeling analysis illustrated the basis of MAO-B ligand binding, revealing a hydrophobic binding pocket, with key residues such as Tyr398 and Tyr435 playing crucial roles in substrate oxidation. MAO-B inhibitors that were reportsed in the literature (2012–2024) and their potential application in cancer therapy were discussed, highlighting key molecular scaffolds, such as propargyl analogs of phenyl alkyl amines, hydrazine derivatives, cyclopropylamine derivatives, MAO-B activated pro-drugs, and natural phenylpropanoid derivatives. The reported literature underscores the therapeutic potential of MAO-B inhibitors as versatile anticancer agents, warranting further investigation to optimize their efficacy and specificity across various malignancies. Full article

Sulfonamide drugs were the original class of antibiotics, demonstrating the antibacterial potential of dithiocarbazate and thiosemicarbazone Schiff base derivatives of syringaldehyde and 4-hydroxy-3,5-dimethylbenzaldehyde. We synthesized unique Schiff bases via the condensation of the aldehydes with hydrazine derivatives, which allows for the easy synthesis of several related compounds. These Schiff base derivatives were tested for antileishmanial properties against the parasitic protozoan Leishmania tarentolae. The inhibitory properties of these sulfur compounds were tested using a series of cell viability and secreted acid phosphatase (SAP) assays. The results demonstrated that compounds ZZ1-04 and ZZ1-20 had potent inhibitory effects on parasite cell viability and SAP, an enzyme that may play a role in infectivity. These results increase our understanding of the role of sulfur in inhibiting Leishmania, providing more knowledge of the structural activity relationships that may prove critical for their development into possible antileishmanial treatments. Full article

New cyclotriphosphazene derivatives featuring amide–Schiff base linkages with a hydrazine bridge and different terminal ends, such as decyl alkyl chains and hydroxy groups, were successfully synthesized and characterized. Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and CHN elemental analysis were used to characterize the structures of these compounds. The formation of hydrazine-bridged cyclotriphosphazene derivatives with amide–Schiff base linkages was confirmed by the FTIR spectra, showing a primary amine band for the amide linkage around ~3300 cm⁻¹ and a band for the Schiff base linkage near ~1595 cm⁻¹. This was further supported by NMR analysis, which displayed an amide proton (H-N-C=O) at ~δ 10.00 ppm and an azomethine proton (H-C=N) within the δ 8.40–8.70 ppm range. The ³¹P NMR spectra of cyclotriphosphazene compounds display a singlet at ~δ 8.20 ppm, indicating an upfield shift that suggests the complete substitution of all phosphorus atoms with identical side chains. Furthermore, CHN analysis verified the purity of the synthesized compounds, with a percentage error below 2%. The introduction of hydrazine bridges and amide–Schiff base linkages into the cyclotriphosphazene core significantly enriches the molecular structure with diverse functional groups. These modifications not only improve the compound’s stability and reactivity, but also expand its potential for a wide range of applications. Full article