A simple and efficient method for the synthesis of pyrazolopyranopyrimidines under solvent-free has been developed. The one-pot multicomponent condensation of arylaldehydes with hydrazine hydrate, ethyl acetoacetate and barbituric acid in the vicinity of a mesoporous basic nanomagnetic catalyst, namely DBU immobilized on Fe3O4@nSiO2@mSiO2 was synthesized in remarkably high yields and in short reaction times. Significantly, this catalyst can be easily separated from the reaction media by applying an external magnet, and can be reused for several cycles.
Graphical abstractAn eco-friendly method for diversity-oriented synthesis of substituted dihydropyrano[2,3-c]pyrazole and benzylpyrazolyl coumarin derivatives has been achieved via one-pot and multicomponent reaction in the presence of PdO/Al-SBA-15 as an efficient and recyclable catalyst in H2O/EtOH under reflux conditions. The significant merits of this method are wide scope, high yields of the desired products, short reaction times and simple workup procedure. In addition, this nanocatalyst was simply recovered and reused five times without significant loss in catalytic activity and also performance.
Graphical abstractThe triethylamine-based nanomagnetic ionic liquid, [(Et)3 N-H]FeCl4, was synthesized, and its structural and chemical characteristics were detected. The thermogravimetric analysis indicated its high thermal stability with a decomposition temperature higher than 300 °C. Additionally, [(Et)3 N-H]FeCl4 was used to efficiently catalyze the synthesis of xanthene derivatives under solvent-free conditions at 120 °C. [(Et)3 N-H]FeCl4 was recycled and reused at least five times.
Graphical abstractIn this research, a new heterogeneous catalyst is fabricated through covalent modification of iron-based metal–organic framework with ionic liquid. In more detail, using 2-aminoterephthalic acid and iron (III) chloride hexahydrate, amino-functionalized metal–organic framework has been synthesized and then reacted with 2,4,6-trichloro-1,3,5-triazine and 1,4-diazabicyclo[2.2.2]octane successively to furnish ionic liquid on metal–organic framework. The as-prepared catalyst was characterized by FTIR, TGA, BET, SEM/EDS, XRD and elemental mapping analysis and then employed for catalyzing synthesis of pyrano [2,3‐d]pyrimidines (with yields of 80–100%) from one-pot three-component reaction of aldehydes, barbituric acid and malononitrile in aqueous media. The catalytic test inferred high catalytic activity of the catalyst, superior to that of IL and metal–organic framework. Furthermore, the catalyst could be recovered and recycled for five reaction runs with preserving its morphology.
Graphic abstractHerein, a green and efficient heterogeneous and photocatalytic system for the oxidation of bisnaphthols in acetonitrile under light-emitting diode will be presented. In this reaction, aerial oxygen and H2O2 have been used as oxidant in the presence of copper ferrite nanoparticles and N-hydroxyphthalimide as an organic co-catalyst. Copper ferrite nanoparticles were magnetically separated, the efficiency of which remained nearly unchanged up to five cycles. Magnetic copper ferrite nanoparticles were synthesized by sol–gel method and characterized by XRD, FT-IR, SEM, TEM, VSM and DRS analysis. In this project, both sets of diastereomers were formed.
Graphical abstractCatalytic system for the oxidation of bisnaphthols.
An efficient and convenient procedure for the synthesis of novel 6-hydroxy-14-aryl-8H-dibenzo[a,i]xanthene-8,13(14H)-dione derivatives has been developed by one-pot, three-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, aromatic aldehydes and 2,3-naphthalenediol in glacial acetic acid under reflux conditions. This domino reaction implies Knoevenagel condensation, Michael addition, intramolecular cyclization and dehydration. The reaction avoids tedious workup procedure due to the direct precipitation of products from the reaction medium. The notable features of this domino transformation are operational simplicity, clean reaction, easy handling, easy purification process and high yields of the products.
Graphical abstractHere, iron, sulfur and poly(ethylene glycol) doping to TiO2 nanoparticles toward the effect on photodegradation of the methylene blue (MB) and Evans blue (EB) was investigated. The present nanostructured photocatalysts displayed notable catalytic activity for the decomposition of colorants in water under visible light irradiation. The photocatalytic reaction constants of different samples were determined for EB and MB to be 0.007, 0.008, 0.009 and 0.01, 0.026, 0.021 1/min, respectively. The values of optical band gap for pure TiO2, Fe–S/TiO2, and Fe–S/TiO2@PEG were estimated to be 3.21, 2.75, and 2.81, respectively. X-ray analysis was performed and correlated with BET, Fe–SEM, and TEM results. The lattice structure was studied by W–H (Williamson–Hall) and H–W (Halder–Wagner) methods with a different assumption in the isotropic and homogenous nature. The results revealed that the SSP model shows the most accuracy and adaption to determine the lattice structure.
Graphic abstractHeterocyclic chemistry has fascinated the researchers owing to its wide range of applications in various chemical fields. With this perspective, herein we present an environmentally benign procedure for the synthesis of pyrazole and its derivatives through multicomponent reaction by using SPVA as a heterogeneous acid catalyst. The synthesis protocol of SPVA catalyst includes functionalization of polyvinyl alcohol by sulfonic acid groups. The synthesized SPVA catalyst was then subjected to several characterization techniques to confirm its formation and study its physicochemical properties. The SPVA catalyst was then tested for its activity toward a multicomponent reaction of aromatic aldehyde, malononitrile and phenyl hydrazine. The SPVA catalyst with sufficient acidic sites displayed appreciable catalytic performance yielding 89% of the desired pyrazole product under ambient reaction conditions. The SPVA catalyst showed recyclability up to the sixth cycle without considerable loss in its activity. Furthermore, we made an effort to demonstrate the plausible mechanistic pathway for the SPVA-catalyzed pyrazole synthesis reaction. Interestingly, the present synthetic approach could effectively produce pyrazole products with high yields in the absence of base and solvent and in short reaction time making it a green and sustainable process.
Graphic abstractA simple, efficient and green approach to the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-diones has been developed via one-pot three-component reaction of aromatic aldehyde, malononitrile and phthalhydrazide catalyzed by zinc–proline complex (Zn[L-proline]2) using H2O: PEG400?=?6: 4 as solvent. Atom economy, good to excellent yield, operational simplicity and easy workup are important features of this method.
Graphical abstractIn this study, the Co-based catalyst was prepared by cobalt immobilization on the surface of functionalized silica-coated magnetic NPs (Fe3O4@SiO2-CT-Co) as a magnetically core–shell nanocatalyst and characterized by FT-IR, TGA, XRD, VSM, SEM, TEM, EDX, EDX mapping, and ICP techniques and appraised in the Suzuki–Miyaura cross-coupling reaction under mild reaction conditions. The results displayed the superparamagnetic behavior of the Fe3O4 NPs core encapsulated by SiO2 shell, and the size of the particles was estimated about 30 nm. Compared with the previously reported catalysts, the engineered Fe3O4@SiO2-CT-Co catalyst provided perfect catalytic performance for the Suzuki–Miyaura cross-coupling reaction in water as a green solvent and it was much cheaper in the comparison with the traditional Pd-based catalysts. Importantly, the durability of magnetic nanocatalyst was studied and observed that it is stable under the reaction conditions and could be easily reused for at least six successive cycles without any significant decrease in its catalytic activity.
Graphic abstractTiO2 nanorods (NRs) have been successfully synthesized via simple hydrothermal technique utilizing TiCl4 as precursor at varied temperature of 160 °C, 200 °C and 250 °C, respectively. Further, thermal treatment was done in the close system at calcinations temperature thrice of the synthesis temperature. The prepared NRs were well characterized for the various physio-chemical natures of the materials. Crystallographic and morphological investigations showed that the samples exhibited high crystallinity with diameter ranges from 300 to 400 nm and length in several micrometers. XPS analysis proved the existence of oxygen defects that were created during the synthesis. The solar photocatalysis showed 81.27%, 92.20% and 58.79% removal of color by NR1, NR2 and NR3, respectively, within 300 min of direct sun irradiation time. The first-order kinetic model fits the better curve with the correlation coefficients of 0.97509, 0.97608 and 0.98417, respectively. Trapping experiments shows the dominant of holes and superoxide as the primary reactive oxygen species.
Graphical abstractd-Sorbitol-cored PAMAM dendrimer (SOR-G1) was effectively synthesized by the ring opening polymerization of epichlorohydrin. The dendrimer was characterized using different spectroscopic and analytical techniques including IR and NMR spectroscopy, TG–DTA, and GPC. Dihydropyrano[3,2-c]chromene derivatives were synthesized using SOR-G1 as a catalyst, and it was synthesized within 30 min in ethanol/water medium and excellent yield was obtained. SOR-G1 acted as a good base catalyst on the basis of amine capacity and good thermal stability. The prepared dihydropyrano[3,2-c]chromene derivatives were characterized using GCMS, LCMS, IR, 1H NMR, and 13C NMR spectra. The catalyst could be reused up to three reaction cycles without losing its catalytic activity.
Graphic abstractThe AHA coupling of amines, haloalkane and alkynes under UV visible light was achieved with a higher yield in the presence of Au/Fe2O3. The catalyst was prepared by two methods using different gold content and then characterized by XRD, UV–vis, BET, TEM, ICP-OES and TPR spectroscopies. A comparative study of the ordinary and photocatalytic conditions, showed that the UV visible light could activate the gold nanoparticles and lead to the formation of CH2Cl? and Cl? radicals through CH2Cl2 fragmentation. The propargylamine was afforded at low temperature and a short time using 2% Au/Fe2O3. The catalyst was stable for five cycles with good photoactivity.
Graphical abstractThe effect of Ce doping and pretreatment of Pt/Al2O3 on its catalysis of propane oxidation was investigated after aging the catalysts. The Ce amount and pretreatment conditions were varied, and the propane oxidation activity was measured. The properties of the catalysts were investigated by means of XRD, STEM-EDX, FT-IR, and H2-TPR. The size of the Pt nanoparticles (PtNPs) decreased for water-treated catalysts doped with a small amount of Ce, suggesting that water treatment of Ce-doped catalysts inhibits Pt sintering. The minimum PtNP size was obtained with ca. 3.6 wt% of Ce. The Ce species with less than 3.6 wt% existed in a dispersed state, whereas above this value, CeO2 particulates co-existed. The propane oxidation temperature of the water-treated catalysts was lowered to an extent that depended on the Ce content. This tendency is consistent with the PtNP size in the catalysts. It is considered that highly dispersed Ce species take a primary role in promoting propane oxidation on PtNPs. The reduction temperature of Ce species on water-treated catalysts was lower than that of untreated catalysts, probably owing to a stronger interaction between Pt and Ce, demonstrated by FT-IR measurements. The increased reducibility of Ce species may be the reason for the improved oxidation activity of the catalysts.
Graphic abstractA series of new mix aza- and thia-macrocyclic glycolipids (9, 10, 16 and 17) have been synthesized and their enantiomeric selectivity was studied. The synthesis of the macrocycles involved a simple protection of two hydroxyl groups of the glycolipids followed by building up the mix-heteroatom macrocyclic in simple sequences. The macrocycles and previously investigated analogues (18, 19, 20 and 21) have been applied as phase transfer catalysts in the enantioselective Michael addition of 2-nitropropane to chalcone and showed good-to-excellent enantiomer excess (ee). Among the catalysts, the galactose aza-crown ether-based glycolipid 21 proved to be the most effective with 90% ee.
Graphic abstractSeveral new derivatives of thiazolidine-2,4-dione and 1-H-imidazole were prepared using imidazole aldehydes 6a–6f in ethanol as a solvent. Products 7a–7f were obtained in reasonable yields and great purity. The antioxidant activity for finish products was evaluated by DPPH radical scavenging activity and showed relatively good activity against ascorbic acid. Compounds 7d, 7e, and 7f had the highest antioxidant activity. Compound 7c showed the lowest amount of IC50 versus ascorbic acid. The antimicrobial activity of these compounds against gram-positive bacteria including Bacillus anthracis (B. anthracis) and Staphylococcus aureus (S. aureus) and gram-negative bacteria including Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) bacteria was evaluated by the inhibition zone diameter assay method, and the compounds showed moderate to low antibacterial activity. The toxicity properties of all synthesized compounds against cisplatin were investigated. Most of the compounds showed good activity against the positive control group, and the toxicity of compound 7b was higher than that of other compounds.
Graphic abstractThe one-pot catalytic conversion of cellulose into ethylene glycol (EG) is an attractive way of biomass utilization. However, low-cost, efficient, and stable catalysts are the premise and research challenges of industrial application. Herein, the magnetic recyclable W–Ni@C catalyst was synthesized by in-situ pyrolysis of Ni-MOFs impregnated with ammonium metatungstate. Compared with the Ni-W bimetallic catalysts prepared by the impregnation method and the sol–gel method, the W–Ni@C catalyst for cellulose hydrogenolysis reaction can achieve a higher ethylene glycol yield (67.1% vs 43.3% and 42.6%) and 100% of cellulose conversion rate. The uniformly dispersed Ni nanoparticles and abundant defective WOx were formed in a reductive atmosphere generated in pyrolysis of Ni-MOFs, which was indispensable for the hydrogenolysis of cellulose into EG. Besides, the hierarchical porous carbon derived from organic ligands in Ni-MOFs reduces the mass transfer resistance while confining Ni nanoparticles and WOx to prevent their leaching, effectively enhancing the stability of the W–Ni@C catalyst. Therefore, the remarkable catalytic performance, the simple and effective recovery method as well as satisfying stability would make W–Ni@C become a promising catalyst for the conversion of cellulose to EG.
Graphical abstractIn this work, the electrochemical performance of Na-doped layered cathode material LiCoO2 for Li-ion batteries is studied using first-principles calculations. The results show that the doped Na ion acts as a pillar, which can greatly increase the diffusion rate of Li ions, but it is not conducive to improving cycle performance and delithiation potential. These research results provide a theoretical reference for the study of Li-ion batteries with high-rate performance. Due to the conflicting role of single element doping, the multi-element co-doping strategy will be the best way to develop high-performance Li-ion batteries.
Graphical abstractN-Methylpyrrolidine catalyzed, concise and attractive synthesis of a new class of 3-hydroxy-3,5/6-di-aryl-1H-imidazo[1,2-a]imidazol-2(3H)-ones was attained with impressive yields, in the presence of EtOH as a solvent, by means of a convenient and elegant condensation reaction between different aryl glyoxal monohydrates and guanidine hydrochloride under reflux conditions. Some specific merits of the current procedure, including encompasses low operating cost, availability of the starting substrates, reasonable reaction times, high reaction yield, operational simplicity, cleaner reaction profile, no harmful by-products, and the isolated product is in pure form. Structures of all the freshly synthesized products have been deduced by their FT-IR, 1H-NMR, 13C-NMR, Mass spectrometry data and microanalysis.
Graphical abstractA green, highly efficient, and eco-friendly protocol for Knoevenagel–Michael addition reaction is reported in Chickpea leaf exudates (CLE) as a naturally sourced biosurfactant. The reactions between dimedone/4-hydroxycoumarins and a variety of aryl aldehydes were carried out in presence of CLE to afford diketodiols/biscoumarins. The synthetic pathway complies with several key requirements of green chemistry principles such as the employment of natural feedstock as green reaction media, ambient temperature, atom economy along with natural biosurfactant type Bronsted acids, and recyclable and biodegradable catalyst which led to a 28-fold increase in molar efficiency versus industrial standard protocols. Its dynamic phase is confirmed by the optical microscopy technique and critical micelle concentration measurement. The notable advantages of the present protocol were simple work-up procedure, high yield within short reaction time, easy separation of products, avoiding tedious column chromatography thus making the protocol environmentally friendly, sustainable, and economical.
Graphical abstract