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In this study, we evaluated the performance of nano-γ-Fe2O3–SO3H catalyst in the Biginelli reaction and synthesized 3,4-dihydropyrimidine-2-(1H)-ones. This reaction was carried out under solvent-free and ultrasonic irradiation conditions and belonged to one-pot multicomponent reactions (MCRs) with an adopted aromatic aldehyde, ethyl acetoacetate, and urea as starting materials for the beginning of the reaction. The synthesized materials were efficient in synthesizing 3,4-dihydropyrimidine-2-(1H)-ones via the Biginelli reaction under reaction conditions. Thus, the advantages of using nano-γ-Fe2O3–SO3H in the Biginelli reaction are short reaction time, high efficiency, green method, solvent free, and cost-effective. Furthermore, nano-γ-Fe2O3–SO3H as a heterogeneous catalyst can be recycled five times without significantly reducing catalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrospun alumina nanofibers exhibit high acidity. • The nature of the acid sites in alumina nanofibers is assessed with IR-Pyridine. • Total acidity and acid sites distribution is assessed with NH 3 -TPD. • Desorption kinetics of adsorbed ammonia (NH 3) using density-functional theory (DFT) is provided. • A mathematical model using a regression procedure is used to estimate NH 3 desorption energy on alumina nanofibers. Alumina (Al 2 O 3) is a widely used material for catalysis in the chemical industry. Besides a high specific surface area, acid sites on Al 2 O 3 play a crucial role in the chemical transformation of adsorbed molecules, which ultimately react and desorb from the catalyst. This study introduces a synthetic method based on electrospinning to produce Al 2 O 3 nanofibers (ANFs) with acidity and porosity tuned using different aluminum precursor formulations. After electrospinning and heat treatment, the nanofibers form a non-woven network with macropores (∼4 μm). Nanofibers produced from aluminum di(sec -butoxide)acetoacetic ester chelate (ASB) show the highest total acidity of ca. 0.70 µmol/m2 determined with temperature-programmed desorption of ammonia (NH 3 -TPD) and BET. The nature of the acid site in ASB ANFs is studied in detail with infrared (IR) spectroscopy. Pyridine is used as a molecular probe for the identification of acid sites in ASB. Pyridine showed the presence of Lewis acid sites prominently. Density-functional theory (DFT) is conducted to understand the desorption kinetics of the adsorbed chemical species, such as ammonia (NH 3) on crystalline γ-Al 2 O 3. For our analysis, we focused on a mobile approach for chemisorbed and physisorbed NH 3. The computational results are compared with NH 3 -TPD experiments, ultimately utilized to estimate the desorption energy and kinetic desorption parameters. The experiments are found to pair up with our simulation results. We predict that these non-woven structures will find application as a dispersion medium of metallic particles in catalysis. [ABSTRACT FROM AUTHOR]

An efficient and rapid four component reaction of ethyl acetoacetate, hydrazine hydrate, malononitrile and different aldehydes at environmentally benign room temperature and solvent free conditions. This research has developed for synthesis of pyranopyrazole derivatives in the presence of CoCuFe2O4 magnetic nanocrystals as reusable catalyst. The catalyst prepared and characterized by FT-IR, XRD, SEM, EDX and VSM techniques. The products confirmed by spectroscopic and physical data such as; melting points, FT-IR and 1H NMR analyses. [ABSTRACT FROM AUTHOR]

A catalyst-free and convenient synthetic route to the green one-pot preparation of dihydropyrano[2,3-c]pyrazole scaffolds via four-condensation domino reaction of tandem Knoevenagel-Michael cyclocondensation reaction of ethyl acetoacetate, hydrazine hydrate, aryl aldehyde derivatives and malononitrile in glycerol as a reusable and biodegradable promoting media has been described. All reactions are completed in short period of times and the products are obtained in excellent yields. The salient features of this green and expedient approach are catalyst-free conditions, a green and biodegradable reaction medium, excellent yields, straightforward work-up with no column chromatographic separation, avoidance of toxic organic solvents and reagents, one-pot procedure, simplicity of operation and high atom-economy. Also, the glycerol was highly stable and could be reused in four successive runs with no significant structural change and loss of activity which makes it highly beneficial to address the industrial needs and environmental concerns. [ABSTRACT FROM AUTHOR]

Herein, we report the first example of green synthesis of hybridized 1,3‐cyclohexadiene (1,3‐CHD) scaffolds in moderate to excellent yields. The catalyst‐free sequential four‐component reaction of 2‐chloroquinoline‐3‐carbaldehydes, 1‐phenyl‐2‐(1,1,1‐triphenyl‐λ5‐phosphanylidene)ethan‐1‐one, ethyl acetoacetate and primary amine in ethanol afforded tetrasubstituted 1,3‐cyclohexadienes bearing 2‐oxo‐1,2‐dihydroquinoline moiety during 4 hours. The structure of the synthesized products was determined via X‐ray analysis. This approach is characterized by its operational simplicity, readily available precursors, green solvent, mild conditions, and moderate to excellent yields. [ABSTRACT FROM AUTHOR]

Some novel substituted benzofurans and annulated furochromenes were obtained through the treatment of the novel (2E)-3-(4,9-dimethoxy-5-oxo-5H-furo[3,2-g]chromen-6-yl)acrylonitrile (2) by some active carbon nucleophiles such as active methylene ketones and methylene nitriles. Thus, the reaction of acrylonitrile 2 with acetylacetone, ethyl acetoacetate, diethylmalonate, and acetoacetanilide in ethanol containing piperidine produced efficiently the corresponding polyfunctionalized benzonitrile derivatives 3–5 and furochromeno-pyridine 6, respectively. Also, treatment of acrylonitrile 2 with some methylene nitriles such as malononitrile, ethyl cyanoacetate, and malononitrile dimer afforded the annulated furochromene derivatives 7–9. Furthermore, the pyrido[1,2-a] benzimidazole system 10 was furnished via reaction of acrylonitrile 2 with 2-(1 H-benzimidazol-2-yl)acetonitrile. These reactions took place through Michael addition, retro-Michael, and γ-pyrone ring opening followed by different types of recyclization. The chemical structures of the novel products were established on the basis of their spectral data and elemental analysis. [ABSTRACT FROM AUTHOR]

ZSM-11 zeolite was synthesized by hydrothermal treatment and cerium ion was incorporated by the ion exchange method. The catalytic activity of cerium modified ZSM-11 zeolite was tested for the one-pot synthesis of 4H-pyran derivatives by cyclocondensation of aromatic aldehyde, malononitrile, and ethyl acetoacetate. The synthesized catalyst was characterized by Powder-X Ray Diffraction, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Fourier Transform Infrared Spectroscopy, Brunauer-Emmer-Teller surface area analysis and Temperature programmed desorption (ammonia) analysis. The present method offers significant advantages over the reported methods like easy separation of catalyst, simple work-up procedure, an excellent yield of desired products, and reusability of catalyst without significant loose in the activity.

Quinoxalin-2-one (1) reacts with ethyl acetoacetate in trifluoroacetic acid (TFA) to form 3-(2-oxopropylideno)-3,4-dihydroquinoxaline-2-one (2) and 3-(3-oxo-3,4- dihydroquinoxaline-2-(1H)-ylidene)methylquinoxaline-2-(1H)-one (3). The reaction product 3 was also obtained by heating the compound 1 with acetone in the presence of TFA.

Deep eutectic solvents formed from hydrated metal chlorides and hydrogen bond donors (Type 4) were prepared and their catalytic activity was compared for the synthesis of dihydropyrimidinones/thiones via Biginelli reaction at room temperature. The one-pot multicomponent reaction was performed between ethyl acetoacetate, various aldehydes and urea/thiourea using DESs. Among the five DESs, excellent conversion was observed using DES 2 (ZrOCl2·8H2O with ethylene glycol at 1 : 2 ratio). The higher activity of DES 2 might be due to the strong hydrogen bonding ability and low viscosity of DES 2, which favoured the reaction as a catalyst. Further, the catalyst was recycled and reused up to four consecutive cycles without significant loss in its activity. The efficiency of the present catalyst was compared with some previous reports. Various structural and quantum chemical parameters (like energy gap), dipole moment, ionization potential, electron affinity, chemical potential (μ), global hardness (η), softness (μ), electronegativity (χ), electrophilicity index (ω) of the pharmaceutically important Biginelli products were investigated using B3LYP functional at 6-31G* level, as implemented in Gaussian 09. [ABSTRACT FROM AUTHOR]

In the present study, a set of different benzoxazole derivatives has been synthesized from ethyl acetoacetate, ethoxymethylene malononitrile, NaNO2, and organic acids. Analytical instruments like proton NMR (¹H), carbon NMR (13C), infrared spectroscopy (IR), and LC-MS mass spectrometry were used for structural characterization. Synthesized molecules were evaluated for In-vitro antioxidant property (DPPH assay, Total antioxidant & reducing power method) and anti-diabetic property (alphaamylase & alpha-glucosidase assay). In silico, studies against Human pancreatic alpha-amylase (PDB ID: 3BAW) have been carried out to get the binding approach of the ligand towards the protein. The results demonstrated that compounds namely 5b, 6b, 3b and 4b had potent antioxidant and anti-diabetic activity compared with ascorbic acid and acarbose. [ABSTRACT FROM AUTHOR]

In this work, a tetradentate acidic catalyst based on pentaerythritol tetrabromide and methylimidazole was designed and synthesized. The catalyst was characterized by Fourier transform infrared, 1H NMR, 13C NMR, and thermogravimetric analysis and its catalytic activity in the synthesis of 1-amidoalkyl-2-naphthols (from 2-naphthol, aryl aldehydes, and amide) and 4,4′-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazole-5-ol)s (from aryl aldehydes, phenylhydrazine, and ethyl acetoacetate), two important classes of compounds, was investigated. The catalyst has multiple interesting properties such as hydrogen bonding interactions, high catalytic activity, heterogeneous feature, and ability to be useful under solvent-free condition. [ABSTRACT FROM AUTHOR]

Recently magnetic nanocatalyst has attracted considerable attention because of its unique properties, including high performance, easy separation from the reaction mixture, and recyclability. In this study, a novel magnetic bionanocomposite was synthesized with chitosan and tannic acid as a natural material. The synthesized bionanocatalyst was characterized by essential analysis. Fe3O4@chitosan-tannic acid as a heterogeneous nanocatalyst was successfully applied to synthesize pyranopyrazole and its derivatives by a one-pot four-component reaction of malononitrile, ethyl acetoacetate, hydrazine hydrate, and various aromatic aldehyde. At the end of the reaction, the nanocatalyst was separated from the reaction mixture and was reused several times with no significant decrease in its catalytic performance. Simple purification of products, the ability for recovering and reusing the nanocatalyst, eco-friendliness, high yields of pure products, mild reaction conditions, short reaction time, non-toxicity, economically affordable are some of the advantages of using the fabricated nanocatalyst in the synthesis of pyranopyrazole. [ABSTRACT FROM AUTHOR]

Concentrated solar radiation (CSR)-assisted synthesis of pyranopyrazole derivatives under solvent and catalyst-free condition has been reported in the present protocol. One-pot multicomponent synthesis from aromatic/heteroaldehyde, ethyl acetoacetate, malononitrile, and hydrazine hydrate leads to the final desired compounds in a good yield. This operationally simple methodology has several advantages such as green and clean reaction profile, simple workup and purification procedures, extremely short reaction time, atom efficiency, and being economical. The current energy-efficient method saves almost 98% of energy as compared to the conventional method. [ABSTRACT FROM AUTHOR]

One-pot multicomponent reaction between aromatic aldehyde, hydroxylamine hydrochloride and ethyl acetoacetate/methyl acetoacetate for the synthesis of isoxazoles derivatives by employing tomato fruit extract as a catalytic medium has been developed. Tomato fruit extract was found to be a favorable catalytic medium for the synthesis of titled compounds. Mild reaction condition, ease of separation, moderate to high yield of the product, and short reaction time makes this method more attractive over earlier reported methods for the synthesis of isoxazoles derivatives. [ABSTRACT FROM AUTHOR]

Comparison of Fe SB 3 sb O SB 4 sb @SiO SB 2 sb @PAMAM(G SB 2 sb )-SO SB 3 sb H with some reported catalysts for synthesis of polyhydroquinoline and dihydro-1 I H i -indeno[1,2 I b i ] pyridine derivatives. It can be concluded from this table that the Fe SB 3 sb O SB 4 sb @SiO SB 2 sb @PAMAM(G SB 2 sb )-SO SB 3 sb H catalyst can be considered as one of the best catalysts for these reactions because of the short reaction times, simple conditions, and environmental friendliness. We also performed the reaction in the presence of Fe SB 3 sb O SB 4 sb , Fe SB 3 sb O SB 4 sb @SiO SB 2 sb , Fe SB 3 sb O SB 4 sb @SiO SB 2 sb @PAMAM(G SB 2 sb ), and ClSO SB 3 sb H separately, but the results were not satisfactory (Table 1, entries 8-11). In summary, we have studied the synthesis of polyhydroquinoline and dihydro-1 I H i -indeno[1,2 I b i ] pyridine derivatives using Fe SB 3 sb O SB 4 sb @SiO SB 2 sb @PAMAM(G SB 2 sb )-SO SB 3 sb H as a nanomagnetic catalyst. [Extracted from the article]

The multi-component reaction of ethyl acetoacetate with each of malononitrile (3) benzaldehyde (1) in ethanol containing triethylamine gave the ethyl 6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carboxylate (4). The latter compound reacted with hydrazine hydrate to give the hydrazide derivative 6. Compound 6 underwent a series of hetero-cyclization reactions to give pyrzole, hydraide-hydrazone, thiazole derivatives. The produced compounds tested against cancer cell lines six cancer cell lines and showed that compounds 8b, 10b, 11a, 17a, 21 and 24a were the most cytotoxic compounds. Further tests of the latter compounds toward the five tyrosine kinases and Pim-1 kinase showed that compounds 10b, 21 and 24a were the most potent of the tested compounds and compounds 10a, 11a and 17a were of the highest inhibitions toward Pim-1 kinase. The high inhibitions of most of the tested compounds toward the selected cancer cell lines and the tyrosine kinases encourage for future work to be done [ABSTRACT FROM AUTHOR]

The reaction of 4-arylidene-2-phenyloxazol-5(4H)-ones with enamines of ethyl acetoacetate gave 4-aryl-2-methyl-6-oxo-5-[(phenylcarbonyl)amino]-1,4,5,6-tetrahydropyridine-3-carboxylic acid esters, which, when heated with phosphorus oxychloride, were converted into esters of 7-aryl-5-methyl-2-phenyloxazolo[5,4-b]pyridine-6-carboxylic acids. Alkaline hydrolysis of these compounds gave 4-aryl-2-methyl-6-oxo-5-[(phenylcarbonyl)amino]-1,6-dihydropyridine-3-carboxylic acid esters. [ABSTRACT FROM AUTHOR]

Pathway engineering is a useful technology for producing desired compounds on a large scale by modifying the biosynthetic pathways of host organisms using genetic engineering. We focused on acetoacetate esters as novel low-cost substrates and established an efficient terpenoid production system using pathway-engineered recombinant Escherichia coli. Functional analysis using recombinant E. coli proteins of 18 carboxylesterases identified from the microbial esterases and lipases database showed that the p-nitrobenzyl esterase (PnbA) from Bacillus subtilis specifically hydrolyzed two acetoacetate esters: methyl acetoacetate (MAA) and ethyl acetoacetate (EAA). We generated a plasmid (pAC-Mev/Scidi/Aacl/PnbA) co-expressing PnbA and six enzymes of the mevalonate pathway gene cluster from Streptomyces, isopentenyl diphosphate isomerase type I from Saccharomyces cerevisiae, and acetoacetyl-coenzyme A ligase from Rattus norvegicus. The plasmid pAC-Mev/Scidi/Aacl/PnbA was introduced into E. coli along with plasmid expressing carotenoid (lycopene) or sesquiterpene (β-bisabolene) biosynthesis genes, and the terpenoid production was evaluated following the addition of acetoacetate esters as substrates. These recombinant E. coli strains used MAA and EAA as substrates for the biosynthesis of terpenoids and produced almost equivalent concentrations of target compounds compared with the previous production system that used mevalonolactone and lithium acetoacetate. The findings of this study will enable the production of useful terpenoids from low-cost substrates, which may facilitate their commercial production on an industrial scale in the future. Key points: • PnbA from Bacillus subtilis exhibits acetoacetate hydrolysis activity. • A plasmid enabling terpenoid synthesis from acetoacetate esters was constructed. • Acetoacetate esters as substrates enable a low-cost production of terpenoids. [ABSTRACT FROM AUTHOR]

Cu(II) supported on 5-oxo-4,5-dihydro-pyrrole-3-carboxylic acid functionalized Fe3O4 nanoparticles (Cu(II)-OHPC-Fe3O4) as a new magnetic nanocatalyst was prepared and characterized by ICP-AES, FT-IR, XRD, SEM, TEM, TGA, XRD, VSM and EDX techniques. Prepared nanocatalyst (Cu(II)-OHPC-Fe3O4) is employed for Pechmann reactions between different substituted phenols and ethyl acetoacetate to obtain new products of coumarin derivatives in good to excellent yields. This green catalyst was easily removed, reused several times with no significant loss of its activity and provided clean synthesis with excellent yield and reduced time. [ABSTRACT FROM AUTHOR]

A facile, low‐cost, and effective one‐pot method was developed for the synthesis of 1,4‐dihydropyridine derivatives with high yields through the three‐component reaction of ammonium acetate, ethyl acetoacetate, and aromatic aldehydes using Fe2ZnAl2O7 as catalyst. The reaction was conducted at 70–80°C temperature under solvent free conditions. The developed method had some great advantages, including safe and clean reaction conditions, high to excellent product yields, short reaction time, and a novel and powerful heterogeneous catalyst. The developed heterogeneous solid catalyst had high efficiency and reusability in one‐pot multi‐component syntheses such that it was easily reused four to five times without significant loss in efficiency and product yield. The catalyst was characterized by scanning Electron Microscopy (SEM)/energy‐dispersive X‐ray spectroscopy (EDS) and X‐ray diffraction techniques. N2 sorption isotherms of the prepared nanocomposite exhibited surface area 2.1313E+01 m2/g and total pore volume of 3.0957E‐02 cm3/g. Substituted dihydropyridine derivatives were characterized and confirmed using 1H NMR and 13C NMR, and elemental spectral data. [ABSTRACT FROM AUTHOR]

Previously published proposals for the production of bromine water without elemental bromine have one thing in common: the didactically valuable experiment for disturbing and re‐establishing an equilibrium using the keto‐enol tautomerism of ethyl acetoacetate cannot be realized. One way out is according to Proske et al. [1] Lange′s proposal [9] for the formation of elemental bromine. This is modified here in order to minimize its risk potential, but considerable experimental skills are required. Müller and Kirsch suggest the electrolytic production of bromine water as a less dangerous variant [10]. Based on this, a specification is proposed here, in order to implement the experiment for keto‐enol tautomerism with the bromine water produced in this way. With the two production variants presented here, the well‐known school experiments with bromine or bromine water can be used in the classroom without the storage of elemental bromine. [ABSTRACT FROM AUTHOR]

In this study, the metal complex (5,10,15,20‐tetrakis‐(4‐sulfonatophenyl)‐porphyrin manganese (III) chloride; denoted as MnTSPP) represents a promising efficient and reusable heterogeneous solid catalyst for facile and highly efficient one‐pot synthesis of 1,4 dihydropyridine derivatives via three‐component condensation reaction of aromatic aldehyde, ethyl acetoacetate, and ammonium acetate under green and mild reaction conditions. The simple operation, short reaction time (15 min), and the high efficiency (99%) are the special advantage of this protocol. Furthermore, the green aspects of this synthetic protocol were more studied by examination of the reusability of MnTSPP for four consecutive cycles without a significant loss of catalytic activity. Remarkably, the new synthesis presented advantages in terms of safety, commercially available catalyst, simplicity, stability, mild conditions, short reaction time, and excellent yields, using a mixture of H2O and C2H5OH environmental‐friendly solvent, operationally facile, wide tolerance of starting materials, and excellent recoverable of the catalyst. [ABSTRACT FROM AUTHOR]

Afterward, the reaction mixture was washed three times with ethyl acetate and hexane (9/1, 10 mL) to remove excess salicylaldehyde from the nano-[Mn-4BSMPC]Cl SB 2 sb . Nano-[Mn-4BSMPC]Cl SB 2 sb was prepared by the reaction of 4-(benzyloxy)benzaldehyde with malononitrile, ethyl acetoacetate and hydrazine hydrate to generate 6-amino-4-(4-(benzyloxy)phenyl)-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile. Thus, nano-[Mn-4BSMPC]Cl SB 2 sb was an efficacious and useful catalyst for the preparation of tetrahydropyridines. Effect of the catalyst amount and temperature on the reaction among 4-nitrobenzaldehyde (2 mmol), aniline (2 mmol) and ethyl acetoacetate (1 mmol). [Extracted from the article]

The main objective of this review is to present an assessment of green synthetic approaches to pyrazole derivatives. An effective and sustainable synthesis of 3,4,5-trisubstituted pyrazoles was reported using B 30 b as a 1,3-dicarbonyl synthon in the presence of hydrazine hydrate, 2% HCl and ethanol at 80 °C to yield pyrazole B 31 b in 68% isolated yield (Scheme 13).[52] PHOTO (COLOR): Scheme 13. Microwave and ultrasound-mediated synthesis Microwave synthesis and ultrasound-mediated synthesis have been used to accomplish the aim of greener approaches to pyrazoles and other heterocycles.[91] The Cheng group reported the formation of novel 3,5-disubstitued-1 I H i -pyrazoles B 19 b by cycloaddition of tosylhydrazones and , -unsaturated carbonyl compounds containing a -hydrogen B 18 b under microwave irradiation in solvent-free reaction conditions (Scheme 48).[92] PHOTO (COLOR): Scheme 48. In their efforts to develop greener and more facile organic transformations Shabaani and coworkers worked on the solvent free four-component synthesis of pyrazolo[1,2-a]pyrazoles and pyrano[2,3-c]pyrazoles. [Extracted from the article]

Organic ligands with long carbon chains have been widely utilized to mediate the growth of halide perovskite crystals with tunable morphologies. However, the presence of these surfactants on the surface of halide perovskites limits their performance in photocatalytic conversion applications. Herein, a rapid synthetic protocol to prepare Cs3Bi2Br9 platelets with clean surfaces and controllable thickness in a dilute H2SO4 solution after a quick cooling process in liquid nitrogen or mixtures of dry ice is reported. Electron microscopy and X‐ray diffraction reveal the preferential exposure of (00l) facets in Cs3Bi2Br9 platelets with variable thickness from 100 to 500 nm. Infrared spectroscopy hints that the selective chemisorption of ethyl acetoacetate on (00l) facets of bismuth perovskites regulates the growth of the crystals. These novel lead‐free halide perovskite platelets can drive the photo‐oxidation of toluene to benzaldehyde with high selectivity (≥88%) and stability over 36 h. [ABSTRACT FROM AUTHOR]

In this study we investigated the cascade heterocyclisation reactions of 1,2‐diamino‐4H‐phenylimidazole with dimethylaminomethylidene (ethoxymethylidene) by the derivatives of acetoacetic ester, acetyl acetone, and aryl(hetaryl)butane‐1,3‐diones. As a result of the studied processes 7‐amino‐2‐R‐3‐R1‐5‐phenylimidazo[1,5‐b]pyridazines were obtained, whose structures were proved by means of 1H NMR, 13C NMR, XRS, and NOESY spectroscopy. Heterocyclisation conditions were optimised to obtain target products with high yields. A probable mechanism for regioselective processes was suggested. It was found that three‐component processes with initial diamine, 1,3‐dicarbonyl compounds and triethyl orthoformate or dimethylformamide dimethylacetal result in similar products. The yield of these reactions was slightly reduced in comparison to the two‐component processes. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents are a class of new generation green solvents formed from two or more components, which furnish a new homogeneous liquid phase with lower melting point than the individual components. Here, for the first time, dual role of DES as catalyst and reaction medium was studied for the synthesis of symmetric dihydropyridine derivatives from aldehyde, ethyl acetoacetate and ammonium acetate. The present article reports the suitability of six DESs for Hantzsch dihydropyridine synthesis at room temperature. Among this, DES 2 (ZrOCl2.8H2O and ethylene glycol at 1:2 ratio) was found to be the catalyst of choice with excellent recyclability. The role of DES in the present protocol was to activate the reactants through strong hydrogen bonding interaction and provide suitable medium for the reaction. The major advantages of DESs for the titled reaction are the easy preparation, low cost, non-volatility, biodegradability, simple catalytic process, excellent conversion and the reusability. [ABSTRACT FROM AUTHOR]

A heterogeneous organic–inorganic hybrid durable nanocatalyst γ-Al2O3@Silane-TMG was prepared by covalently functionalization of nano-γ-Al2O3 through anchored 3-chloropropyl- trimethoxysilane with 1,1,3,3-tetramethylguanidine (TMG). The structure of the catalyst was characterized by various techniques including FT-IR, XRD, SEM, EDX and TGA analyses. The synthesized nanocatalyst was successfully used in an efficient and green four-component synthesis of pyrazolopyranopyrimidine derivatives using ethyl acetoacetate, hydrazine hydrate, arylaldehydes and barbituric acid (or thiobarbituric acid) in H2O at 40 ºC. This practical method produced the desired products at reduced reaction times (10–25 min) and high to excellent yields (85–98%). The main advantages of this practical method are the use of heterogeneous basic nanocatalyst, simple work-up procedure with no need to chromatographic purification, affording highly selective conversion and recyclability of the catalyst which could be used in 5 cycles with only a small decrease in its activity. [ABSTRACT FROM AUTHOR]

Amino acid polyoxometalate nanoparticles-embedded microcapsules were in situ fabricated by layer-by-layer (LbL) self-assembly method [isopolyoxometalate, Mo8O26·nH2O; amino acid, aspartic acid (AFO)]. Aspartate functionalized γ-octamolybdate (AFO) [Co2(C4H6NO4)2(Mo8O26)(H2O)10]·4H2Owas employed as heterogeneous catalyst for efficient, diverse, and high yielding synthesis of spirochromenes via a three-component reaction involving isatins or acenaphthenequinone, malononitrile or ethyl cyanoacetate, and various 1,3-diketones (dimedone, barbituric acid, or ethyl acetoacetate) or 4-hydroxycoumarin/3-methyl-1H-pyrazol-5(4H)-one in water/ethanol under reflux. The AFO is characterized by some physico-chemical approaches such as elemental analysis, ICP, IR, and UV–Vis spectroscopies and PXRD analyses. Notably, the heterogeneous catalyst AFO, containing molybdenum atom as the basis and appropriate redox nature, reinforced with the organic metal fragment in its structure, showed effective catalytic activity, and could be recovered simply from the reaction mixture and reused at least three runs without significant loss of its catalytic activity. This prolific combination of amino acids and isopolyoxometalates inaugurates a powerful class of porous catalysts for the different chemical transformations, which overcomes key limitations of previously established salts and Lewis acidic metals based catalysts under low catalyst loading, the use of water scavengers, dry solvents, and additives for facilitating the specialized experimental setups commonly employed to the organic reactions. [ABSTRACT FROM AUTHOR]

• Aromatic chalcones serve as the fundamental building block of numerous crucial biological compounds, and the feature of skeletal modification to produce a new class of organic heterocyclic compounds. • Michael's addition reaction is the most significant carbon-carbon bond-forming in organic synthesis, numerous medicines are considered to be anti-carcinogens and anti-inflammatory are connected via Michael's addition reaction. • Derivatives of cyclohexenone are formed by cyclo-condensation of chalcones and ethyl acetoacetate, under the influence of NaOH, the presence of active groups linked to the cyclohexenone ring is responsible for the excellent anticancer and antibacterial activities. Two new cyclohexenone carboxylate derivatives (6a-b) were synthesized through an additional ring-forming chalcone. FT-IR, 1H, 13C NMR, and Mass spectroscopy techniques confirmed the skeletons. The antibacterial, antioxidant, and colon cancer HT-29 cell activity of synthetic substances were assessed. Compound 6a 's IC50 is 23.95 and 60.28 for its antioxidant and anticancer activities, whereas Compound 6b's IC50 is 27.56 and 62.72, respectively. MIC values for compound 6a are 15.75 ± 1.12, 10.25 ± 1.27, and 65.61 ± 1.72 against Staphylococcus aureus, Escherichia coli bacterial strains, and Candida albicans, respectively, whereas for compound 6b is equal to 18.32 ± 1.53, 12.63 ± 1.36, and 78.91 ± 1.94. Based on the extent of (B3LYP) and a 6-31G (d, p) basis set, the HOMO and LUMO of synthesized compounds were computed using the density functional theory (DFT) method. Energy gaps for products 6a and 6b are 2.8272 and 2.3360, respectively. Docked products had binding affinities of −9.5 and −9.1 for compounds 6a and 6b , respectively, with the crystal structure of recombinant human acetylcholinesterase in complex with donepezil (PDB ID: 4ey7). Consequently, according to experimental and computational studies, compound 6a is more active than compound 6b. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis of [ZeoDABCO-SO 3 H]-Cl Bronsted acidic heterogeneous catalyst. • The catalyst is utilized for the synthesis of 2,3-dihydropyrimidines-2-ones/ thiones in excellent yields. • The promising cytotoxicity activity against normal kidney cell lines. • An analysis of the human LTA4H protein's molecular docking against leukotriene A4 hydrolase. • Molecular Docking Results of (4a-j) series compounds with epidermal growth factor receptor tyrosine kinase In the present study, synthesis of material supported [ZeoDABCO-SO 3 H]Cl Bronsted acid heterogeneous catalyst was synthesized and investigated in the reaction between aryl aldehydes, ethyl acetoacetate, and urea/thiourea for the synthesis of Dihydro pyrimidines-2-ones/ thiones in excellent yields. The synthesized [ZeoDABCO-SO 3 H]Cl is reusable for six runs without suffering a significant loss of catalytic activity, according to reusability research. The existing technology has a variety of advantages, involving ambient reaction conditions, use of ethanol as green solvent, high yield, less time, and simple workup processes. Additionally, we have investigated the promising cytotoxicity against normal kidney cell lines, with the latter validated by a study of molecular docking. [Display omitted] [ABSTRACT FROM AUTHOR]

A Convenient and green synthesis of 4H-pyran derivatives via one-pot multicomponent reaction of aromatic aldehydes, malononitrile and ethyl acetoacetate using KOH loaded CaO as a catalyst under solvent free condition is reported. The morphology of the catalyst has been characterized by XRD and TEM. This protocol have numerous advantages like lesser reaction time, environment friendly, low cost, easy to separate, and provide higher yield. The synthesized compounds have been characterized and confirmed by different spectroscopic techniques like 1H NMR, 13C NMR, FT- IR, and LC- MS.

The aim of present investigation is the synthesis of mesoporous catalyst based on hexagonal mesoporous silica. HMS support has exceptional properties such as easy synthesis, high surface area, large pore volume and wormhole pores. These distinctive characteristics beseem use of it as a support for synthesis of heterogeneous catalyst. With functionalization of HMS and immobilization of Zr-rhodanine complex into functionalized HMS, HMS/Pr-Rh-Zr was obtained. New synthesized catalyst (HMS/Pr-Rh-Zr) characterized by FT-IR, XRD, TGA, SEM, EDX, adsorption–desorption of nitrogen at 77 K and ICP techniques. These techniques confirmed that the heterogeneous catalyst of HMS/Pr-Rh-Zr was successfully synthesized. Also the catalytic activity of HMS/Pr-Rh-Zr is investigated for the synthesis of tetrahydrobenzo[b]pyran derivatives from reaction between aldehyde, malononitrile, dimedone in PEG at 80 °C and synthesis of 1,4-dihydropyrano[2,3-c]pyrazole derivatives from reaction between aldehyde, ethyl acetoacetate, malononitrile and hydrazine hydrate in H2O:EtOH at 35 °C. These results confirmed the HMS/Pr-Rh-Zr exhibited good catalytic performance. Furthermore, the synthesized heterogeneous catalyst could be recovered after the reaction and reused several times without any noticeable loss in activity. Also zirconium leaching of HMS/Pr-Rh-Zr was studied whereupon metal leaching of the catalyst was very low. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In the present protocol, biogenic synthesis of ZnO nanoparticles using an aqueous extract of weed, i.e. Parthenium is efficiently carried out. The proficient and operationally simple catalytic application of biogenic ZnO nanoparticle is explored towards a synthesis of pharmaceutically relevant and densely functionalized polyhydroquinolines by condensation of four components viz. aromatic aldehyde, dimedone, ethyl acetoacetate, and ammonium acetate. The synthesized polyhydroquinolines were screened for their antimicrobial activity against bacteria and fungi; some of them exhibit better to excellent activity. The developed protocol is enriched with captivating advantages such as excellent yields, shorter reaction time, recyclable catalyst and constructive use of an aqueous extract of Parthenium for the synthesis of ZnO nanoparticle. [ABSTRACT FROM AUTHOR]

one-pot three-component reactant system contains ethyl acetoacetate, hydroxylamine hydrochloride with various aromatic aldehyde, gives isoxazole derivatives by using sodium hypophosphate as a catalyst using the microwave method. The reaction is carried out in ethanol as a solvent medium, under mild conditions gives a good yield in a very short period. The cyclo condensation reaction was carried out in ethanol during the product formation process. The catalyst uses in this reaction act as a non-toxic, easy setup process, short periods, and soluble in ethanol with easily removed by washing with water. [ABSTRACT FROM AUTHOR]

Synthesis of 1,2,4-Triazolo[1,5-a]pyrimidines The main strategies used to prepare [1,2,4]triazolo[1,5-a]pyrimidines have been classified into two routes: fusion of the pyrimidine nucleus to a triazole system and annulation of a triazole to a 1,3-diazine system. Annulation of the 1,2,4-triazole ring to the pyrimidine nucleus Acyl hydrazides were condensed with Schiff bases of the amino-pyrimidine system in the presence of iron(III) chloride to afford triazolo[1,5-a]pyrimidines.[96] The process was performed at room temperature by blending reagents using a mortar; then water extraction and recrystallization were carried out (Scheme 23). Use of Modified 5-Amino-1,2,4-triazoles Scheme 10a shows two parallel paths of pyrimidine ring annulation: the conventional method (A) and route B using a reactive 2-aminotriazole derivative.[57] Thus 2-benzoyl-3-(dimethylamino)acrylonitrile B 29 b was condensed with 5-amino-1,2,4-triazole to give the target 7-phenyl-[1,2,4]triazolo[1,5-a]pyrimidine-6-carbonitrile B 32 b (Path A). Synthesis of compounds 39a-h. The synthesis of 7-phenyl-1,2,4-triazolo[1,5-a]pyrimidine B 41a b from the cyclocondensation reaction of I i -enaminone B 40a b with aminotriazole under ultrasound irradiation was also evaluated. [Extracted from the article]

Bromination of (diethoxyphosphorylmethyl)acetylfurans with dioxane dibromide in the mixture of chloroform and acetic acid in presence of traces of hydrogen bromide at room temperature proceeds selectively at the methyl group of ketone does not involving phosphonate group. Obtained bromoacetyl derivatives were used for alkylation of acetoacetic ester and cyclohexan-1,3-dione. Reaction of 1,4-diketone prepared from acetoacetic ester with hydrazine hydrate in ethanol at room temperature leads to formation of furylpyrazines due to aromatization of intermediate azines by means of air oxygen. [ABSTRACT FROM AUTHOR]

A green and easy protocol for Dihydro-pyrano[2,3-c]pyrazoles, were synthesized in the presence of Ceria-Molybdenum mix metal oxides (Ce-Mo MMO) as a recyclable solid heterogeneous Lewis acid catalyst and one-pot four-component synthesis from the reaction between 3-nitro benzaldehydes, malononitrile ethyl acetoacetate and hydrazine hydrate Here, the Ce-Mo MMO catalyst was designed, prepared and utilized as a catalyst in a various organic reaction. The present protocol offers several superiorities like short reaction time, high percent yield, clean reaction, simple separation technique and recoverable catalyst and it also shows the same catalytic activity when it was reused in consecutive reaction. [ABSTRACT FROM AUTHOR]

A simple, green, and efficient protocol has been developed for the synthesis of biologically active 1,4dihydropyrano[2,3c]pyrazole derivatives via one-pot four-component reaction of various substituted benzaldehydes, hydrazine hydrate or phenylhydrazine, ethyl acetoacetate, and malononitrile in aqueous medium in the presence of sugarcane bagasse ash-based silica-supported boric acid (SBA-SiO2-H3BO3) as a solid acid catalyst. The advantages of this methodology are the use of cost-effective and nontoxic catalyst, short reaction time, operational simplicity, high yields (90–95%), availability of silica source, and green protocol. [ABSTRACT FROM AUTHOR]

The compounds (4,6-dimethyl-pyrimidin-2-yl)-(5-methyl-2-substituted phenyl/H-pyrazol-3-yl)-amines and (4,6-dimethyl-pyrimidin-2-yl)-(5-methyl-2-substituted benzoyl/isonicotinoyl-pyrazol-3-yl)-amines have been synthesized by microwave irradiative cyclocondensation of N-(4,6-dimethyl-pyrimidin-2-yl)-3-oxo butyramide with substituted hydrazines and acid hydrazides respectively. The required butyramide has been synthesized by the condensation of 2-amino-4,6-dimethyl pyrimidine with ethyl acetoacetate under microwave. The pyrimidine linked pyrazol-3-yl amines on acylation afforded mono/di-acetyl derivatives. Structural elucidation of synthesized compounds has been performed by IR, ¹H NMR and mass spectral studies besides chemical transformation and elemental analysis. Title compounds have been screened for their insecticidal activity against Pseudococcidae insects and evaluated for antibacterial potential against some selected microorganisms to establish the structure activity relationship. [ABSTRACT FROM AUTHOR]

In this research, we report the first example of the use of multiwalled carbon nanotubes/guanidine/Ni (II) as a new and effective catalyst. The supported catalyst was prepared through a new method and characterized by Fourier transform infrared, scanning electron microscopy, energy‐dispersive spectroscopy, inductively coupled plasma, thermogravimetric analysis, ultraviolet diffuse reflectance spectroscopy, and transmission electron microscopy. Obtained catalyst was used for green and efficient synthesis of pyrazolopyranopyrimidines via four‐component reaction of hydrazine hydrate, ethyl acetoacetate, barbituric acid, and aromatic aldehydes under ultrasonic condition. All products were obtained in high yields and short reaction times. Also, the prepared catalyst was easily separated from the reaction mixture and reused for several times without significant loss of activity. [ABSTRACT FROM AUTHOR]

A group of Novel phenylhydrazone derivatives of ethyl acetoacetate was synthesized and evaluated for their antiplatelet activities. Fourteen ethyl acetoacetate phenylhydrazone derivatives were synthesized using the diazonium salt of various aromatic primary amines with good yields and purity. The structure of the final compounds was confirmed and approved by spectroscopic techniques such as 1HNMR, FTIR, and ESI-Mass. We examined the antiplatelet activity of the derivatives against Arachidonic Acid (AA) and Adenosine Diphosphate (ADP) as platelet aggregation inducers. The final results indicated the acceptable potency for different derivatives. In this regard, the para-hydroxyphenylhydrazine derivative of ethyl acetoacetate has the best activity among all derivatives, both on AA and ADP pathways. It seems that the derivatives with electron-releasing substituents (hydroxyl, methoxy, and methyl group) have better inhibition activities against the aggregation induced by AA. In contrast, those with an electron-withdrawing group showed a significant decrease in their potency. Based on the results of this study, we would proceed with further assessments both in-vitro and in-vivo to get success in introducing some new antiplatelet agents to the clinic. [ABSTRACT FROM AUTHOR]