Search

In the present study, the synthesis and catalytic application of a novel thioglycolic acid doped on Fe3O4 nanomagnetic particles coated with tris(hydroxymethyl)aminomethane (THAM) and 1,2-dichloroethane are described. The morphology, structure, and physicochemical properties have elucidated by several analytical methods like FT-IR, TEM, VSM, XRD, TGA, and FE-SEM. This nanocatalyst has successfully applied as a heterogeneous acid catalyst in the synthesis of diversely substituted biologically important xanthene and 3-aminoisoxazole derivatives. This catalyst eliminates our need for long-time reaction and hard catalyst separation from product, and it can be easily recovered with an external magnet for eight consecutive times without a significant decrease in its catalytic properties.

In this study, new derivatives of aminoanthraquinone have been synthesized via one-pot three-component condensation reaction of 1- and 2-amino anthraquinones, triethyl orthoformate and CH-acid compounds without using any solvent or catalyst in mild temperature (50 °C). This simple and efficient method yields the desired products in short reaction time (14–50 min) and good to excellent yields (85–96%). Moreover, chemical structures of synthesized products have been entirely confirmed by FT-IR, 1H and 13CNMR and mass spectroscopy and melting points.

In this article, a one-pot three-component synthesis of 3-aminoisoxazolmethylnaphthol derivatives has been developed using Fe3O4–NHPhSO3H as a recyclable heterogeneous nanocatalyst using available 3-aminoisoazoles, aldehyde derivatives and 2-naphthol under solvent-free conditions. This environmentally friendly methodology with excellent green chemistry credentials, such as using the low loading of reusable, nontoxic, easy- to-handle catalyst, shorter reaction time without any byproduct, avoidance of hazardous organic solvents and easy workup (the catalyst can be easily separated from the reaction mixture by an external magnet), can be used in a wide range of applications. A one-pot three-component synthesis of 3-aminoisoxazolmethylnaphthol derivatives has been developed via Fe3O4–NHPhSO3H as a recyclable heterogeneous nanocatalyst by available 3-aminoisoazoles, aldehyde derivatives and 2-naphthol in solvent-free conditions. This green process with main aspects such as operational simplicity, good-to-excellent yields, low cost, easy handling, being eco-friendly and reusability of the catalyst, absence of any tedious workup or purification and avoidance of hazardous or toxic reagents/catalysts/solvents opens an effective and convenient way to naphthalen-2-ol-functionalized isoxazole systems, which are promising compounds for different biomedical applications.

Currently green chemistry techniques are attracting wide attention due to their environmental, health, and economic benefits. These green techniques include the use of polyethylene glycol (PEG-400)...

Fulvic acid is a naturally occurring organic compound found in soil and plants. It is recognized for its ability to balance and energize cell biological processes. Fulvic acid literally transforms ...

A simple and efficient one-pot process for the synthesis of 1,8-dioxo-octahydroxanthene and 2,2′-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives via the Knoevenagel–Michael cascade reactions of aromatic aldehydes and dimedone catalyzed by Bronsted acidic ionic liquids (BAILs) in solvent-free and aqueous conditions is described in this study. These heterocycles were prepared in the presence of Bronsted acidic ionic liquids as a suitable, economical, readily synthesized and eco-friendly catalyst. This method offers several advantages such as high yields, simplicity of the workup, low cost, short reaction times, green conditions and use of a reusable catalyst.

Polysubstituted phthalimide derivatives have been isolated in excellent yield from the addition reaction between acetoacetanilide and dialkyl acetylenedicarboxylates by using DABCO as an efficient basic catalyst in EtOH at room temperature. This procedure led to the formation of new phthalimide derivative in the presence of di-tert-butylacetylendicarboxylate as acetylenic ester. The methodology has also been applied successfully for the synthesis of novel piperidine substitutes via the simple reaction between acetoacetanilide and alkyl propiolates. These reactions have some advantages such as not only the process is eco-friendly but also the yields are good and the work-up is simple.

Novel spirooxindole-furo[2,3-c]pyrazole derivatives containing both biologically active pyrazole and spirooxindole-furan templates are synthesized via single-pot two-step four-component reaction in...

The development of environmentally friendly and economical methods for the synthesis of biologically active heterocycles using readily available reagents remains a significant challenge in organic ...

Novel fused 4,5-dihydro-1 H-furo[2,3- c]pyrazole derivatives containing both biologically active pyrazole and furan templates are synthesised by a one-pot two-step four-component domino reaction involving hydrazine hydrate, a β-keto ester, an aromatic aldehyde and a pyridinium salt catalysed by DABCO with high diastereoselectivity in H2O under microwave irradiation. To minimise the formation of byproducts, the hydrazine hydrate and ethyl acetoacetate were first irradiated until a pyrazolone was formed. Next, the aryl aldehyde, the pyridinium salt and DABCO were added and the reaction could be completed in good to excellent yields. The salient features of this eco-friendly methodology are highlighted by its short reaction time (10–12 min), high yields, high atom-economy, efficiency of producing five new bonds (2C–C, C=N, C–N and one C–O), two new rings and two stereocentres in a single operation, absence of any tedious work-up or purification and avoidance of separation of intermediates.

Novel benzo[a]phthalazino[2′,3′:1,2]pyrazolo[3,4-c]phenazines containing both biologically active benzophenazine and pyrazolophthalazine templates are synthesized using a single-pot, five-component...

The potassium carbonate was applied as a green and efficient catalyst for the one-pot synthesis of pyran annulated heterocyclic systems, via the condensation between aromatic aldehydes, malononitrile and dimedone/1-naphtole by a grinding method at room temperature and solvent-free conditions. Short reaction times, environmentally friendly procedure and excellent yields are the main advantages of this procedure which makes it more economic than other environmentally synthetic methods.

Chromenes, the oxygen-containing heterocyclic compounds, have a “special” place in biologically active natural products and in synthetic chemistry and in the fields of medicinal, agrochemical, cosmetic, and pigment industries. In this work, piperidine was used as a base catalyst for the convenient synthesis of 1,4-dihydropyrano[2,3-c]pyrazole, 5,10-dihydro-4H-benzo[g]chromene, and pyrazolo[1,2-a] [1,2,4]triazole derivatives at ambient temperature. This methodology has several advantages including the use of easily accessible and inexpensive catalysts, short reaction times, high yields, convenient work-up, and not needing column chromatography.

We synthesized Co 0.25 Cu 0.25 Mn 0.5 Fe 2 O 4 @CMC (CCMFe 2 O 4 @CMC) nanorods as a new dual-modal simultaneous for magnetic resonance imaging contrast agent and nanocarrier for drug delivery system. Impact of CCMFe 2 O 4 @CMC nanorods were investigated on the longitudinal (T1), transverse (T2) and transverse (T2 ∗ ) relaxation times for in vitro MRI contrast agent in water and also for drug delivery system, l -dopa was coated on CCMFe 2 O 4 @CMC nanorods and then in vitro drug release test was carried out at three PHs values and different temperatures. In vitro MR imaging demonstrated that r 2 value of CCMFe 2 O 4 @CMC nanorods is 138.33 mM −1 s −1 , CCMFe 2 O 4 @CMC is useful as T2 contrast agent relative to other T2 contrast agants. In vitro drug release test shows the amount of released l -dopa from CCMFe 2 O 4 @CMC nanorods at medium with pH = 1.2 is more than pH = 5.3 and 7.4.

Magnetic iron(III) oxide nanoparticles (Fe3O4 MNPs) have been used as a readily available, highly efficient, and recyclable catalyst for the green and stereoselective synthesis of novel functionali...

l-Proline has been used as an efficient, reusable, and bifunctional organocatalyst for the one-pot, two-step, five-component synthesis of novel 1,4-dihydrobenzo[a]pyrido[2,3-c]phenazines by the condensation reaction of 2-hydroxynaphthalene-1,4-dione, aromatic 1,2-diamines, aldehydes, ammonium acetate, and ethyl acetoacetate under conventional heating in solvent-free conditions. In this domino transformation, six bonds and two new rings are efficiently formed. High yields, short reaction time (20–30 min), operational simplicity, easy work-up procedure, avoidance of hazardous or toxic catalysts and organic solvents are the main advantages of this green methodology.

For the first time, the organic salt Na2EDTA was used as a catalyst for an effective and facile preparation of spiro-4H-pyrans via single-pot three-component condensation of isatin/acenaphthoquinone/ninhydrin, malononitrile, and CH-acids through Knoevenagel–Michael–annulation sequence. This new protocol employing Na2EDTA, which is a green, recyclable, and inexpensive catalyst, offers advantages such as solvent-free and highly efficient reaction conditions, short reaction times (10–15 min), easy work-up and high yields which make it more economic than other environmentally synthetic methods.

Caffeine was applied as a green and natural catalyst for the one-pot, four-component sequential condensation between 2-hydroxy-1,4-naphthoquinone, aromatic 1,2-diamines, ammonium thiocyanate and acid chlorides in the presence of a basic ionic liquid (1-butyl-3-methylimidazolium hydroxide) to afford the corresponding benzo[ a ][1,3]oxazino[6,5- c ]phenazine derivatives. In this one-pot transformation, five bonds and two new rings are efficiently formed. This protocol has the advantages of operational simplicity, high yields, easy workup, avoidance of hazardous or toxic catalysts and organic solvents and high chemo- and regioselectivities.

A simple and convenient multi-component domino reaction has been described for the synthesis of novel spirofuran-indenoquinoxaline derivatives. Products were obtained by a three-component condensation reaction between ninhydrin, aromatic 1,2-diamines and dialkyl ethynedicarboxylates in the presence of a catalytic amount of triphenylphosphine in $$\hbox {CH}_{2}\hbox {Cl}_{2}$$ at ambient temperature in excellent yields. This one-pot process produces biologically and pharmacologically significant heterocycles with the formation of five new bonds (one C–C, two C=N and two C–O) and two new rings in a single operation.

An efficient, convenient and environmentally benign procedure for the synthesis of novel 3-oxo-3H-benzo[a]pyrano[2,3-c]phenazine-1-carboxylate and 3-(5-hydroxybenzo[a]phenazin-6-yl)acrylate derivatives has been developed by domino three-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines and acetylenic esters in the presence of a catalytic amount of DABCO as an expedient, eco-friendly and reusable base catalyst in water. This green process produces biologically and pharmacologically significant heterocycles in a one-pot single operation and offers considerable advantages such as: operational simplicity, short reaction time, high yields, reusability of catalyst, absence of any tedious workup or purification and avoids hazardous reagents/solvents.

An efficient and green strategy for the improved synthesis of a biologically and pharmaceutically interesting multi-functionalized diverse novel spiro-benzo[a]phenazine annulated heterocycles was developed with the assistance of microwave irradiation. A sequential one-pot, two-step domino reaction starting from 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, a cyclic carbonyl compound, and 1,3-indandione in the presence of a basic ionic liquid (1-butyl-3-methylimidazolium hydroxide) as an expedient, ecofriendly and reusable catalyst afforded the corresponding novel spiro[benzo[a]indeno[2′,1′:5,6]pyrano[2,3-c]phenazine] derivatives with high yield under solvent-free conditions. This domino Knoevenagel–Michael annulation reaction provided five new bonds (two C–C, two CN, and one C–O) and two new rings through multiple operations in a single flask.

5-Carboxanilide-dihydropyrimidinone derivatives were synthesized in good yield in a three-component and efficient process by the condensation reaction of acetoacetanilide, aldehyde and urea/thiourea in the presence of cobalt(II) nitrate hexahydrate as catalyst in ethanol at ambient condition.

p-Toluenesulfonic acid was applied as an efficient, non-toxic and solid acid catalyst for the one-pot, four-component condensation between 2-hydroxy-1,4-naphthoquinone, benzene-1,2-diamine, cyclic 1,3-dicarbonyl compounds and isatin or ninhydrin to afford the corresponding novel spiro[benzo[a]chromeno[2,3-c]phenazine] derivatives via a new two-step domino protocol under conventional heating and microwave irradiation. This solvent-free process produces biologically considerable heterocycles with the formation of five new bonds (two C–C, two C˭N, and one C–O) and two new rings in a single operation and this effective green process provides considerable advantages such as: operational simplicity, very short reaction time, high yields, absence of any tedious process or purification, and it avoids hazardous reagents/solvents.

A green, convenient, high yielding and one-pot procedure for the synthesis of novel spiro[benzo[a]pyrano[2,3-c]phenazine] derivatives by domino multi-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, ninhydrine, and malononitrile in the presence of a catalytic amount of 1,3-dimethyl-7H-purine-2,6-dione (theophylline) as an expedient, eco-friendly and reusable solid base catalyst under thermal, microwave irradiation and solvent-free conditions. This procedure has also been applied successfully for the synthesis of benzo[a]pyrano[2,3-c]phenazines.

An efficient, convenient, and environmentally benign procedure for the synthesis of novel benzo[$a$]chromeno[2,3-$c$]phenazine derivatives has been developed by domino four-component condensation reaction between 2-hydroxynaphtha- lene-1,4-dione, $o-$phenylenediamine, aromatic aldehydes, and naphthols or phenol in the presence of a catalytic amount of DABCO as an expedient, ecofriendly, and reusable base catalyst under microwave irradiation in EtOH/H$_{2}$O (1:1). This green process produces biologically and pharmacologically significant heterocycles in a single one-pot operation and offers considerable advantages such as operational simplicity, short reaction time, high yields, reusability of the catalyst, absence of any tedious workup or purification, and avoidance of hazardous reagents/solvents.

Polyfunctionalized heterocyclic compounds have an important role in the drug discovery process and analysis of drugs in late development. Piperidines and their analogues have received attention owing to their biological activities, because of the importance of these heterocycle compounds, there is still a need to improve the ways for green synthesis of these compounds. In this study, lactic acid was applied as a green and efficient catalyst for the one-pot five-component synthesis of highly substituted piperidines from the reaction between aromatic aldehydes, aromatic amines, and b-ketoester at ambient temperature. This methodology has a number of advantages such as: use of easy access and green catalyst, short reaction times, high yields, and easy work-up (just simple filtration).

1,4-Diazabicyclo[2.2.2]octane (DABCO) has been used as an efficient and reusable solid base catalyst for the rapid and green synthesis of pyran annulated heterocyclic ring systems by the co...

A highly efficient one-pot, two-step microwave-assisted procedure was applied for the rapid and green synthesis of benzo[a]phenazine annulated heterocyclic ring systems from the three- or four-component condensation reactions of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aromatic aldehydes and 1,3-indandione using L-proline as a bifunctional organocatalyst in water. This new procedure has a number of advantages such as high yields, very short reaction times, operational simplicity, simple work-up procedures and avoidance of hazardous or toxic catalysts and organic solvents. Moreover, the catalyst can be recovered and reused several times without much loss of its performance.

An efficient, three-component strategy for the improved synthesis of a pharmaceutically interesting diverse kind of multi-functionalized benzofurans via one-pot two-step domino protocol with high diastereoselectivity in excellent yields has been established. The synthesis was achieved by reacting phenacyl bromides, N-heterocycles, aromatic aldehydes, and cyclic 1,3-dicarbonyl compounds in the presence of a catalytic amount of DABCO (1,4-diazabicyclo[2.2.2]octane) as an inexpensive, impressive, and readily available catalyst in water under reflux. In this process in total three new bonds (two C–C and one C–O) form in one pot. Short reaction time, excellent yields, no chromatographic purification, and evasion of environmentally hazardous or toxic catalysts and organic solvents in the entire reaction process may make this protocol very useful for academia and industry.

A sequential one-pot four-component reaction for the efficient synthesis of novel 16-(aryl)benzo[a]indeno[2′,1′:5,6]pyrano[2,3-c]phenazin-15(16H)-one derivatives has been developed. The synthesis was achieved by reacting 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamine, aromatic aldehydes, and 1,3-indandione in the presence of oxalic acid as a reusable and homogenous organocatalyst in EtOH/H2O (1:1) under reflux. The present approach of this methodology offers several advantages such as high yields, clean reaction profiles, operational simplicity, simple work-up procedures, and green aspects by avoiding toxic catalysts and solvents.

Benzo[a]pyrano[2,3-c]phenazine and benzo[f]pyrano[2,3-h]quinoxaline derivatives were synthesized via a one-pot, two-step procedure from a three-component condensation reaction of 2-hydroxynaphthalene-1,4-dione, 1,2-diamines, and tetracyanoethylene in the presence of pyridine as an efficient catalyst. This novel procedure has the advantages of operational simplicity, short reaction times, easy work-up, avoiding costly syntheses, and the products do not require further purification, which provides an efficient and economical method for the synthesis of related products in excellent yields.

An efficient p-toluenesulfonic acid catalyzed synthesis of 11H-benzo[a]benzo[6,7]chromeno[2,3-c]phenazine-11,16(17H)-dione derivatives has been described by one-pot, four-component condensation of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aromatic aldehydes using polyethylene glycol as solvent. This domino protocol produces biologically considerable heterocycles with the formation of C–C, C=C, C–N, C=N, C–O bonds in a single operation and this efficient green process provides significant advantages such as: operational simplicity, easy work-up procedure, high yields, avoidance of hazardous or toxic catalysts and organic solvents, and is devoid of inessential derivatization and generation of hazardous substances.

An efficient, convenient and environmentally benign procedure for the synthesis of novel 1,2-dihydrobenzo[a]furo[2,3-c]phenazine derivatives with high diastereoselectivity has been developed by a domino four-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, aromatic aldehyde and pyridinium ylide in the presence of a catalytic amount of theophylline as an expedient, eco-friendly and reusable solid base catalyst in water. This one-pot process produces biologically and pharmacologically significant heterocycles with the formation of five new bonds (two C–C, two CN and one C–O) and two new rings in a single operation and this effective green process provides considerable advantages such as: operational simplicity, short reaction time, high yields, reusability of catalyst, absence of any tedious workup or purification and avoiding hazardous reagents/solvents.

5-Carboxanilide-dihydropyrimidinone derivatives were prepared by three-component Biginelli reaction of acetoacetanilide, aromatic aldehydes and thiourea in the presence of CeCl3 as an expedient catalyst and used as key intermediates for the highly efficient and eco-friendly synthesis of new and densely functionalized thiazolo[3,2-a]pyrimidin derivatives with use of dimethyl and diethyl acetylenedicarboxylate in ethanol at ambient temperature (conventional magnetic stirring).

A one-pot, two-step procedure has been used to synthesize functionalized benzo[a]pyrano[2,3-c]phenazine derivatives from a four-component condensation reaction of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aldehydes, and malononitrile in the presence of 1,3,7-trimethylpurine-2,6-dione (caffeine) as an expedient and reusable solid base catalyst. This new procedure has the following advantages: operational simplicity, short reaction times, environmentally friendly, easy work-up, and all the products were obtained in excellent yields.

Superparamagnetic nanoparticles of modified vitamin B3 (Fe3O4@Niacin) represent a new, efficient and green biocatalyst for the one-pot synthesis of 2-amino-3-cyanopyridine derivatives via four-component condensation reaction between aldehydes, ketones, malononitrile, and ammonium acetate under microwave irradiation in water. This new magnetic organocatalyst was easily isolated from the reaction mixture by magnetic decantation using an external magnet and reused at least six times without significant degradation in the activity. The catalyst was fully characterized by FT-IR, XRD, SEM, VSM, UV–Vis, DLS and EDS. Excellent yield, very short reaction time (7–10 min), operational simplicity, easy work-up procedure, avoidance of hazardous or toxic catalysts and organic solvents are the main advantages of this green methodology which makes it more economic than the other conventional methods.

A new and efficient isocyanide-based one-pot multi-component reaction has been described for the synthesis of novel ?-spiroiminolactone derivatives. Products were obtained by a three-component condensation reaction between isocyanides with acetylenic esters which was trapped with 6H-indeno[1,2-b]pyrido[3,2-e]pyrazin-6-one (aromatic ketone) in CH2Cl2 without use of any catalyst or activator in excellent yields.

Silica sulfuric acid (SiO2–SO3H) has been used as an effective and reusable solid catalyst for the one-pot, two-step, four-component microwave-assisted synthesis of benzo[a]chromeno[2,3-c]phenazine derivatives by the condensation reaction of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aldehydes, and cyclic 1,3-dicarbonyl compounds. This new procedure has a number of advantages such as: high yields, very short reaction time, operational simplicity, simple work-up procedures and avoidance of hazardous or toxic catalysts, and organic solvents and is devoid of inessential derivatization and generation of hazardous substances. Moreover, the catalyst shows high thermal stability and can be recovered and reused without loss of reactivity.