In this work, an efficient and scalable synthetic route has been established for the assembly of structurally diverse triazolo[4,3-a]pyrimidine derivatives from readily available starting materials. Central to this approach is an NH-selective heterocyclization, which proceeds smoothly under mild reaction conditions and is governed by the thermodynamic preference for the triazolopyrimidine scaffold, as quantitatively demonstrated by calculated free energy differences. The structures of all newly synthesized compounds were unambiguously determined by & sup1;H NMR, & sup1;& sup3;C NMR, and high-resolution mass spectrometry. Notably, single-crystal X-ray diffraction analysis of compound 6s showed unequivocal confirmation of molecular architecture and provided mechanistic insight into the cyclization process. Preliminary biological assays demonstrated that several target compounds displayed potential antiproliferative effects against HepG2 cancer cells. Computational docking analyses revealed that compounds 6l and 7j bind to EGFR in a mode highly similar to that of a known reference inhibitor, highlighting its promise as a scaffold for further medicinal chemistry optimization. These studies not only broaden the triazolopyrimidine heterocyclic system but also lay a foundation for the further design and discovery of novel anti-tumor agents.
For many years, FDA-approved medications and pharmaceutically active compounds have included S-heterocycles (thiazole, thiophene, and thiazolidinine). Scientists are becoming more interested in other heterocycles, especially S-heterocycles, due to the extensive study of N-heterocycles in medicinal chemistry. S-heterocycle derivatives have shown promise in the development of new drugs that can enhance pharmacokinetic characteristics, reduce toxicity, and overcome drug resistance. This review study presents rational approaches for developing antibacterial medications against methicillin-resistant Staphylococcus aureus (MRSA) based on the structure–activity correlations (SARs) of pharmacologically attractive S-heterocycles. Thus far, enough work has been done to collect potent anti-MRSA S-containing compounds, develop SARs, and secure patents for this remarkable molecule. Because S-heterocycles are easily modified and have a wide range of biological effects, particularly in the fight against MRSA, researchers may be able to develop new drugs.
Thiourea SC(NH2)2 (1), sulfur analog of urea (2), possesses unique hydrogen-bonding ability, mesomeric effects, and tautomeric versatility, making it a valuable scaffold in pharmaceuticals, agrochemicals, and materials science. Thiourea derivatives have diverse physical, chemical and biological properties. This review consolidates recent advances (2015–2025) in the synthesis of thiourea derivatives, emphasizing green methodologies: ultrasound-assisted, photochemical, solvent-free, and on-water reactions. Biological activities, i.e. antibacterial, antifungal, antiparasitic, antioxidant, antidiabetic, anti-inflammatory, antiviral, enzyme inhibitory and herbicidal are critically analyzed with a focus on structure–activity relationships (SAR), substituent effects, and chirality. Notable progress includes derivatives that are effective against drug-resistant pathogens and synergistic antifungal mixtures. By identifying research gaps (toxicity, selectivity, scalability) and advocating for sustainable synthesis, this review positions thiourea derivatives as versatile leads for next-generation therapeutic and agricultural solutions.
When benzaldehyde, acetophenone, and thiourea are condensed in the presence of HCl, a compound, which is 4,5,8a-triphenylhexahydropyrimido[4,5-d]pyridine-2,7(1H,3H)-dithione (THPD) is derived (Barbero et al., A Br & oslash;nsted acid catalysed enantioselective Biginelli reaction. Green Chem. 2017;19:1529-1535. doi:). The structure of the compound synthesized was confirmed by using the single crystal X-ray diffraction technique, which showed that the asymmetric unit consisted of two crystallographically independent molecules with the core being a fused hexahydropyrimido[4,5-d]pyrimidine. The hydrogen bonding and aromatic ring interactions to support crystal packing were investigated by Hirshfeld surface analysis. The electronic structure and charge-transfer properties of the title compound were investigated using density functional theory (DFT) calculations to complement the experimental crystal structure. The results of single-crystal X-ray and optimized geometrical parameters are satisfactory and support each other. The frontier molecular orbital analysis reveals a moderate HOMO-LUMO energy gap, indicating balanced charge-transfer capability and chemical stability. Natural bond orbital investigations and molecular electrostatic potential studies underline strong intramolecular N-S-C conjugation and donor-acceptor nature, which is consistent with the solid-state packing nature, as reported. Molecular docking studies against human DNA topoisomerase II alpha revealed moderate binding affinity and favorable interactions within the protein-DNA binding region.
A novel basic Fe3O4-carbon coated magnetic nanocatalyst (BFCMNPs) was designed and prepared through a facile procedure using inexpensively available reagents. The procedure involved initial preparation of Fe3O4@C followed by its treatment with KOH to afford Fe3O4@C@OK (BFCMNPs). The catalyst was characterized by EDX, TGA, TEM, SEM, FTIR, and XRD methods. The catalytic performance of BFCMNPs was demonstrated in one-pot three-component tandem aldol-thia-Michael combination of acetophenone derivatives with aromatic aldehydes and thiols, where it could act as an environmentally benign, efficient, and easy to recover catalyst to provide the respective 3-(arylthio)propan-1-one adducts in aqueous medium. Use of commercially available starting materials, short reaction times, safe solvent usage, high yields of products, easy procedure, and convenient recovery of the catalyst by applying an external magnetic field and its reuse in seven consecutive runs are the advantages of the present method.
A method for the acylation of phenols, alcohols, thiols, and amines has been described using carboxylic anhydrides as acylation agents in the presence of a metal triflimide Lewis superacid catalyst. Metal triflimides active for the acylation include copper triflimide, zinc triflimide, manganese(II) triflimide, cobalt triflimide, and lanthanum(III) triflimide. The acylation reaction proceeds readily at room temperature in neat or in anhydrous dichloromethane, and various functional groups such as cyano, ether, ester, halogen, keto, heteroaryl, and nitro are well tolerated. Based on mechanistic studies using 2,6-di-tert-butyl-4-methylpyridine (DTBMP) as a non-coordinating base, the metal catalyst undergoes either hydrolysis or hydration to release a Br & oslash;nsted acid are as the actual catalytic species. The Br & oslash;nsted acid activates the carboxylic anhydride through protonation and makes it susceptible to nucleophilic substitutions as well as competitive hydrolysis.
Mercury is a typical trace pollutant found in coal combustion flue gas. Due to the high toxicity and mobility of Hg, particularly Hg0, its removal from flue gas is difficult. Currently, significant efforts are being made to maximize Hg0 adsorption rates while minimizing their impact on power operation costs. Among the various approaches, sulfur-modified activated carbon exhibits excellent mercury removal characteristics. Therefore, this study investigated the mechanism of mercury adsorption on different sulfur forms and adsorption sites using density functional theory. The results show that linear and cyclic sulfur molecules exhibit varying adsorption capabilities for mercury on zigzag and armchair activated carbons. Linear S7 exhibited the highest chemical adsorption energy on the zigzag carbon, whereas cyclic S7 was the most stable on the armchair carbon. Among the cyclic sulfurs, S5 exhibited the strongest chemical adsorption on the zigzag carbon, with most of the remainder being physically adsorbed. Notably, the long-chain sulfur on the armchair carbon tend to break, facilitating mercury adsorption, with S7 and S8 performing well and falling under physical adsorption conditions. The adsorption mechanisms of different sulfur allotropes loaded onto carbon models described herein provide a theoretical direction for the development of highly efficient sulfur-modified carbon-based adsorbents.
The limited van der Waals force between MoS2 and the graphene substrate in MoS2/graphene heterojunctions can lead to problems such as partial aggregation of MoS2 nanosheets, uncontrollable geometric structures, and loose binding of the robust scaffold. To address these issues, this study explored a strategy of coating MoS2 with dopamine and carbonizing it under microwave-assisted conditions to optimize the lithium storage structure. The research results showed that MoS2/polydopamine mass ratio of 1:1 and microwave radiation power of 700 W were the optimal process conditions for the preparation of MoS2@C composite materials. At this point, MoS2 was completely embedded in the carbon framework, and the carbon layer provided good electrical conductivity and could suppress the structural changes of MoS2. The MoS2@C structure exhibited excellent adsorption performance for Li+, which was beneficial for the storage and transfer of Li + during charge and discharge cycles.
Herein, a new set of chiral beta-seleno amide ligands was designed by merging the skeleton of cyclic amino acid with amino selenide for Cu-catalyzed enantioselective Friedel-Crafts alkylation reactions of indoles. A wide variety of indoles and (E)-2-Alkenoyl-pyridines were tested in this reaction, furnishing corresponding products in up to 93% yield and 60% ee.
The low cost and facile availability of the green and natural catalysts has been documented for numerous synthetic and catalytic uses owing to the presence of various types of functional groups. Because they include a variety of functional groups, green and natural catalysts are inexpensive and easily accessible, and their numerous synthetic and catalytic applications have been reported. Therefore, we have explored the utilization of these natural catalysts for the synthesis of (E)-5-arylidenethiazolidine-2,4-dione in the current study. The yields vary according to the circumstances of the reactions. (E)-5-arylidenethiazolidine-2,4-dione has been synthesized by using different aromatic aldehydes and thiazolidine-2,4-dione. The efficiency of several natural catalysts (fruits and vegetables) in the presence of different solvents has been studied. According to our studies, the (E)-5-arylidenethiazolidine-2,4-dione can be achieved with a 55-78% yield as the desired product with the use of the natural catalyst as a green, sustainable method.
Novel thiazole-oxadiazole hybrids (8a-j) were synthesized and investigated for their antidiabetic activity against alpha-glucosidase as an enzymatic target. The synthesized hybrid compounds displayed notably excellent inhibitory activity; amongst all examined heterocyclic hybrids. Compounds para-nitro and-chloro substituted on the phenyl ring hybrids exhibited a similar to 1.5-fold and 2-fold magnificent alpha-glucosidase inhibition (IC50 = 2.74 and 1.98 & micro;g/mL), as associated with the acarbose standard drug, 3.89 & micro;g/mL. Structural establishment of the heterocycles bearing the electron-withdrawing (NO2) group at the para-and meta-positions on the phenyl ring significantly affected the inhibitory activity. The fabricated molecular hybrids demonstrated superior binding to the alpha-glucosidase enzyme. Molecular docking examines these hybrid compounds in the active site of the alpha-glucosidase enzyme to describe and emphasize the alleged binding interfaces ascribing to selective inhibition. [GRAPHICS] .
This study presents a theoretical investigation of five D-pi-pi-A organic sensitizers for dye-sensitized solar cells (DSSCs). Density Functional Theory (DFT) and Time-Dependent DFT calculations were performed using the omega B97XD/6-31+G(d,p) method to evaluate their structural, optoelectronic, optical, and photovoltaic properties. The influence of donor modification on charge-transfer behavior was systematically analyzed through frontier molecular orbital distribution, HOMO/LUMO energy levels, energy gaps, excitation energies, oscillator strengths, light-harvesting efficiencies (LHE), open-circuit voltage (Voc), and electron injection driving forces. The calculated absorption maxima range from 400 to 600 nm, indicating good visible-light absorption. All sensitizers exhibit favorable energy alignment with the TiO2 conduction band and electrolyte redox potential, supporting efficient electron injection and dye regeneration. Among the studied dyes, CM5 shows the strongest red-shifted absorption at 575 nm and the smallest HOMO-LUMO gap, while CM2 exhibits the highest Voc and best electron injection driving force. CM1 demonstrates excellent light-harvesting efficiency with a high oscillator strength. These findings highlight the strong effect of donor engineering on DSSC photovoltaic performance.
To fully understand the catalytic hydrodesulfurization of the most refractory sulfur-containing compound 4,6-dimethyldibenzothiophene (DMDBT) is important for the progress of ultra-deep hydrodesulfurization (HDS) technology. 1,2,3,4-tetrahydro-4,6-dimethyldibenzothiophene (4H-DMDBT) plays a critical role in the kinetic study of DMDBT hydrodesulfurization. Through existing methods, it is very difficult to obtain sufficient 4H-DMDBT for mechanism study. In this work, we have developed an expeditious and scalable synthetic route featuring cheap starting materials, safe and green reagents and procedures that is suitable for an organic synthetic laboratory.
In this work, the reaction pathways and products resulting from the reactions S-1(3) + O-3(2) and S-1(4) + O-3(2) are investigated using three different quantum chemistry methods. The thermochemistry of formation, isomerization and degradation reactions for all species involved in these systems is evaluated in detail and the corresponding reaction profiles, including reactants, transition states, and products, are reported. Enthalpies are calculated at the CBS-QB3, G3, G4 levels of theory. Entropy and heat capacity contributions as functions of temperature are determined from the optimized molecular structures, moments of inertia and vibrational frequencies. Kinetic parameters are obtained using canonical transition state theory (TST) calculations. All reaction pathways in both systems ultimately lead to (S2O)-S-1, (SO)-S-3, S-3, S-3(2), and (SO2)-S-1 as final products. The calculations indicate that analogous reaction types in the two systems exhibit similar rate coefficients. [GRAPHICS] .
Sulfur-containing compounds in petroleum products pose significant risks to environmental quality and human health. During combustion, these compounds, particularly sulfur dioxide (SO2), are released into the atmosphere, contributing to air pollution and acid rain. Conventional desulfurization methods, such as hydrodesulfurization, are capital- and energy-intensive and require costly catalysts, increasing operational expenses. In contrast, adsorption offers a simpler, low-energy alternative capable of removing sulfur compounds under mild conditions. Despite extensive research on activated carbon, agricultural waste-based adsorbents remain underutilized, especially in regions where such materials are abundant. This study developed a cost-effective adsorbent for sulfur removal from diesel and kerosene using locally sourced biomass. Batch adsorption experiments evaluated the effects of contact time (4-48 hours), adsorbent dosage (1-10%), and initial sulfur concentration (10 ppm, 50 ppm, 100 ppm, and 189.7 ppm). The synthesized adsorbents, particularly the CNS 1:4 formulation, showed superior performance compared to commercial activated carbon, achieving removal efficiencies of 80.92% for kerosene and 71.8% for diesel. Adsorption followed both the Langmuir and the Freundlich isotherms, yielding a high correlation coefficient (R & sup2; = 0.977) and conformed to a pseudo-second-order kinetic model, indicating chemisorption. These findings highlight cashew nut shell-derived activated carbon as an efficient, economical, and sustainable material for fuel desulfurization.
In our previous work, we reported the one-pot synthesis of novel fused mesoionic heterocycles of the 1-substituted-5-thioxo-5,6-dihydro-[1,2,4]triazolo[1,5-c]quinazolin-1-ium-2-thiolate series. In the present study, we have further developed and significantly improved this methodology. A simplified one-step procedure was achieved by employing 2-isothiocyanatobenzonitrile instead of the corresponding ester, which markedly streamlined the synthetic protocol and broadened the reaction scope. The improved method afforded higher yields for several compounds previously described and enabled the preparation of new derivatives with diverse substituents. All synthesized compounds were fully characterized by elemental and spectroscopic analyses. Considering that NMR and LC/MS methods alone cannot provide unambiguous structural confirmation for these systems, the meso-ionic product structure was conclusively established by single-crystal X-ray diffraction. A conceptual DFT analysis was performed on the obtained structure.
A novel series of beta-(thiosemicarbazide/thiosemicarbazone)-sulfide derivatives (6a - i and 8a - k) was synthesized through a streamlined multi-step approach designed to yield new antibacterial candidates. Structural elucidation was accomplished using comprehensive spectroscopic techniques. The antibacterial efficacy of the synthesized compounds was evaluated via minimum inhibitory concentration (MIC) assays against multiple bacterial strains. Notably, compounds 6d, 6e, and 6 h demonstrated potent and selective activity against Klebsiella pneumoniae (K. pneumoniae) with MIC values of 50 & micro;g/mL, compared to the reference drug ciprofloxacin (MIC >= 32 & micro;g/mL). These compounds also exhibited significant antioxidant activity in DPPH radical scavenging assays, with inhibition ranging from 75.13% to 83.74%, approaching that of ascorbic acid (87.5%). Molecular docking studies further supported their potential, revealing stable binding interactions with the active sites of K. pneumoniae topoisomerase IV and carbapenemase enzymes. Collectively, these findings highlight the dual antibacterial and antioxidant potential of the synthesized derivatives, positioning them as promising candidates for further development, particularly against multidrug-resistant K. pneumoniae.
