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The combination of two or more pharmacophoric subunits is an important and efficient strategy in organic synthesis for the construction and architecture of more effective drugs. With the use of thi...

In this work, the synthesis of 1,3,4-oxadiazole derivatives using triphenylphosphine dibromide/triethylamine (Ph3P/Br2/Et3N), 1,2-bis(diphenylphosphaneyl)ethane/2Br2/Et3N, and nano-silica-anchored PPh2/Br2/Et3N systems is described. The method allows the preparation of 1,3,4-oxadiazoles with a broad substrate scope from easily accessible materials.

The hydrothermal synthesis of ZnO–NiO–NiFe2O4 nano-composite is reported. The sample was utilized to characterize via XRD, FE-SEM, EDS, FT-IR, UV–Vis, and BET techniques. The sample consisted of three different phases as ZnO (hexagonal), NiO (cubic), and NiFe2O4 (cubic) with the average particle size as 34 nm and specific surface area, average pore diameter, and pore volume as 64.35 m2 g−1, 13.02 nm, and 0.201 cm3 g−1, respectively. Catalytic behavior of the nano-composite was investigated on the synthesis of thiazolidin-4-one derivatives under thermal and ultrasonic irradiation condition. Our results show that the catalytic activity of ZnO–NiO–NiFe2O4 nano-composite is much higher than ZnO, NiO, and NiFe2O4 metal oxides. All products were prepared in high yields with short reaction times. In addition, the catalyst was recovered for at least five times.

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)...

A naturally biodegradable, reusable, and eco-safe catalyst, i.e., uric acid was developed and exploited for the green, facile and economical one-pot synthesis of pyran annulated heterocyclic system...

In this work, thiocarbohydrazide doped iron nanoparticles as a novel, green, heterogeneous, and inexpensive catalyst is reported. This catalyzed the three components reaction of dialkylacetylenedicarboxylate with aromatic aldehydes and aromatic amines to yield the corresponding furan derivatives EtOH. An indispensable part of green chemistry is to be able to recover and reuse catalysts without any notable drop in catalytic activity. The analysis of catalyst and application of that for the synthesis of title compounds in high yields reveal this property. The formation, size of the metal ions present in the material is confirmed by powdered X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). Keywords: Nano particles, Heterogeneous catalyst, Thiocarbohydrazide, Green chemistry

Reaction of pyridine-2-(1H)-one derivatives (diamines) and 1,2-dicarbonyl compounds in the adjacency of acetic acid, a solvent, inexpensive and green catalyst, at 50 °C produced new 1,2,4-triazine ...

Heterocyclic 1,2,4-triazoles and their derivatives, such as triazolopyridines, have been used as leading components for the synthesis of numerous heterocyclic compounds; and because of their various biological activities, they have a distinct location in pharmaceutical and medicinal chemistry. In this article, we demonstrate a new way of synthesizing 1,2,4-triazolo[1,5-a]pyridine derivatives, as a one-pot pseudo-three-component reaction, via the reaction of pyridine-2-(1H)-one derivatives and 1,4-cyclohexadione in the adjacency of acetic acid both as solvent and an inexpensive and green catalyst at 50 °C. The desired products were synthesized in good yields, and the chemical structure of the synthesized compounds was recognized using 1H and 13C NMR spectra, FT-IR, melting point, mass spectroscopy, and elementary analysis.

Green multi-component domino reactions (MCRs)1–7 for the synthesis of fine chemicals have attracted much recent interest.8–9 Quinolines, spiro[4H-pyran-oxindoles] and xanthenes are reported as havi...

A one-pot three-component condensation reaction of 3-amino-5-methylisoxazole, aryl aldehyde and 2-naphthol to afford the corresponding 3-amino isoxazolmethylnaphthols in good to excellent yields. The remarkable features of this new procedure are high conversions, clean reaction condition, short reaction time, nonhazardous and environmentally friendly reaction condition, inexpensive and easily commercially availability of the catalyst and simple work-up procedures.

A convenient and straightforward acid-promoted synthesis of a new series of polyfunctionalized pyrroles has been developed based on a one-pot three-component reaction of acetoacetanilide, benzoin, and ammonium acetate/diverse anilines in acetic acid as a green solvent at 100 °C. The other salient benefits of this transformation include being simple reaction conditions, toxic transition-metal-free, no need of column chromatographic purification, moderate to good yields, eco-friendliness, and readily available starting materials.

This method reported the use of tartaric acid as a green and highly efficient catalyst for the convenient synthesis of polysubstituted quinolines and xanthenes derivatives in excellent yields under solvent-free conditions. The main advantages of this one-pot procedure are the green and economic availability of the catalyst, simple experimental and work-up procedures.

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.

Caffeine was found to be a natural and green and biodegradable catalyst for the one-pot, three-component condensation Biginelli reaction of ?-keto esters, aromatic aldehydes and urea/thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones/thiones derivatives under solvent-free conditions. The remarkable features of this green procedure are high yields, short reaction times, simplicity of operation and work-up procedures, the availability and easy handling of this solid catalyst, avoidance of hazardous or toxic catalysts and organic solvents and economic availability of the catalyst.

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...

A facile synthetic strategy has been reported for the diastereoselective synthesis of N,N′-diaryl-2-aryl-6-hydroxy-6-methyl-4-oxocyclohexane-1,3-dicarboxamide via Et3N-catalyzed. Acetoacetanilide undergoes a diastereoselective condensation reaction with various aromatic and aliphatic aldehydes in EtOH at 50 °C to afford desirable products via one-pot pseudo-three-component reaction. The present protocol provides an inexpensive and efficient route to obtain functionalized cyclohexanones containing four quaternary stereogenic centers with high yields from the simple and readily available starting materials under mild conditions in shorter reaction times. The products have been characterized by IR, 1H NMR, and 13C NMR spectroscopy. The stereoselectivity of compounds was established with crystallography and NMR spectroscopy.

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.

An environmentally benign three-component synthetic method is described for the construction of 2-aryl-4-phenylquinazoline derivatives from the reaction between aldehydes, ammonium acetate, and 2-aminobenzophenone in the presence of lactic acid in a solvent-less media. The benefits of the reaction were good yields, a simple procedure, simple starting materials short reaction time, easy work-up, and cleaner reaction profiles.

Fumaric and maleic acids are utilized as two environmental-friendly and efficient catalysts for a one-pot, pseudo five-component coupling reaction, containing aromatic amines, aromatic aldehydes and methyl acetoacetate/ethyl acetoacetate. In this work, a variety of differently substituted aldehydes and amines were tolerated very well, affording cyclic compounds with two consecutive stereogenic centers in moderate to high yields and with excellent diastereoselectivities. In this research, the catalytic effect of maleic acid is compared with that of fumaric acid. According to the obtained results in the presence of both of them, products were produced with the same streochemistry. These reactions were performed under mild conditions to yield 1,2,5,6-tetrahydropyridine-3-carboxylate derivatives with good to excellent yields (46–91%). When fumaric acid was used instead of maleic acid as catalyst the yields of products were relatively low. This is probably because of the stereochemistry of fumaric acid. The main benefits of this process are the easy work-up, short reaction times, green catalysts and no chromatographic purifications. The work-up of these reactions involves only a filtration and a simple washing step with EtOH, and there is no need for column chromatography.

A facile and benign synthetic strategy is proposed for the synthesis of 2-arylpyrroloacridin-1(2H)-ones via a lactic acid-catalyzed three-component reaction of dimedone, various anilines, and isatins under solvent-free conditions. Avoidance of hazardous organic solvents, the use of a one-pot multicomponent procedure for the synthesis of 2-arylpyrroloacridin-1(2H)-ones, operational simplicity, no need for column chromatography, lactic acid utilization as a bio-based organic compound, reusability, homogeneity, and commercial availability of the catalyst, and superior synthetic performance are some important aspects of this methodology to access a series of pyrroloacridine motifs with potentially biological scaffolds.

Lactic acid, as a biological, eco-friendly, and inexpensive compound, efficiently catalyzed the synthesis of 8,10-dimethyl-12-aryl-12H-naphtho[1′,2′:5,6]pyrano[2,3-d] pyrimidine-9,11-dione derivati...

This article aimed to present two facile and environmental friendly routes for the rapid assembly of biologically active compounds including pyrazol core using aspirin as a novel and green catalyst. The synthesis of bis(pyrazol-5-ol) derivatives was developed via one-pot, pseudo-five-component condensation, and the target dihydropyrano[2,3-c]pyrazoles and spiropyranopyrazoles were prepared by one-pot, four-component reaction. These reactions can be performed in tandem from readily available starting materials. The main merits of the present methods are operational simplicity, no need for column chromatography, inexpensive materials, avoidance of harmless and corrosive acid catalysts, short reaction times, good yields of the products, and utilization of aspirin as a non-toxic, cheap, commercially available, and efficient catalyst.

Multi-component reactions (MCRs) are pivotal because of their versatility for the generation of interesting heterocyclic scaffolds and libraries of biologically active molecules. They have several ...

An eco-friendly and environmentally benign synthesis of 3,4,5-substituted furan-2(5H)-ones employing Iranian seedless barberry, known as Zereshk, (Berberis integerrima “Bidaneh”, Berberidaceae) as a biocatalyst, was developed. For the fi rst time, we found that the barberry juice could be effectively used for three-component condensation reaction of aldehydes, amines, and dialkyl acetylenedicarboxylates. The merits of this method include the environmentally friendly reaction conditions, simple operation, broad substrate, satisfying yields, and the generation of less waste rather than the conventional chemical reagents.

A straightforward, one-pot multicomponent synthesis of 1-(benzothiazolylamino)methyl-2-naphthol derivatives was achieved by condensation of 2-naphthol, aldehydes, and 2- aminobenzothiazole catalyzed by a small amount of citric acid, which acts as a benign enviermentally catalyst. Mild conditions with excellent yields and a simple isolation procedure are noteworthy advantages of this method.

Medicinally important 2-arylpyrrolo[2,3,4-kl]acridin-1(2H)-ones are synthesized by a straightforward, efficient and convenient approach of three-component reactions of dimedone, various anilines, and isatin in the presence of acetic acid as environmentally benign and effective catalyst, under solvent-free conditions at 80 °C. This work presented here has the merits of environmental friendliness, easy operation, simple work-up, excellent yields, and inexpensive catalyst.

A simple synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives via one-pot four-component condensation reaction of phthalimide, hydrazine monohydrate, aromatic aldehyde derivatives and malononitrile in the presence of a catalytic amount of zirconium tetrachloride (ZrCl4) as a mild and efficient Lewis acidic catalyst under thermal and solvent-free conditions with good yields and short reaction times is developed. This present methodology has notable benefits such as high efficiency, inexpensive and non-toxic catalyst, environmentally benign nature, solvent-free conditions and simplicity of operation.

One-pot, efficient three-component condensation of aromatic aldehydes, 2-naphthol and 2-aminobenzothiazole in the presence of oxalic acid as an organocatalyst and effective catalyst for the synthesis of 1-(benzothiazolylamino) methyl-2-naphthol derivatives under thermal and solvent-free conditions is described. The present approach of this methodology offers several advantages such as high yields, clean reaction profiles, operational simplicity, being environmentally benign, lack of need for column chromatography and simple work-up procedure.

An efficient and benign protocol leading to the synthesis of benzoxanthene derivatives using a multi-component reaction consisting of aromatic aldehydes, dimedone and 2,7-dihydroxynaphthalene or β-naphthol in the presence of lactic acid as an efficient, inexpensive and green catalyst under solvent-free conditions is reported. Operational simplicity, good yields, short reaction time, moderate and eco-friendly conditions, and no need for column chromatography make this present methodology more innovative than existing ones.

A series of biologically active polysubstituted dihydropyrrol-2-ones are prepared via a one-pot four-component reaction of structurally diverse dialkyl acetylenedicarboxylate, formaldehyde, and amines (aromatic and aliphatic) using a catalytic amount of tartaric acid as a naturally green, mild di-functional Bronsted acid catalyst at ambient temperature. The use of tartaric acid as an inexpensive catalyst makes this procedure eco-friendlier and also one-pot, easily separated from the reaction mixture, good to high yields, short reaction times, simple operational procedures, and highly efficient that are the added advantages of the present methodology.

The use of chromium(III) nitrate nonahydrate (Cr(NO3)3·9H2O) as an efficient, mild and economical catalyst for the one-pot three-component Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-one/thione derivatives in the reaction between β-keto esters (methyl or ethyl acetoacetate), aromatic aldehydes (benzaldehye derivatives) and urea or thiourea under thermal and solvent-free conditions with good yields and short reaction times is reported. The most benefits of this synthetic method include the use of an efficient, eco-friendly, inexpensive and non-toxic catalyst, as well as the solvent-free conditions. All products were characterized by 1H NMR spectroscopy and melting point determination.

We have studied the catalytic ability of copper(II) acetate monohydrate as a mild, environmentally benign, natural and economical catalyst for the multi-component efficient synthesis of biologically active spiro-4H-pyran derivatives and 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives with excellent yields and short reaction times. The most important advantages of this procedure are its mild, non-toxic and inexpensive catalyst, one-pot synthesis, environmentally benign nature, solvent-free conditions, simple operational procedures, and highly efficient conditions.

We have developed an efficient diastereoselective synthesis of poly-substituted hydroquinolines from commercially available starting materials, Meldrum’s acid, aromatic aldehydes and arylamines, in a simple and one-pot reaction using Bronsted acidic ionic liquid (4-sulfobutyl)-tris(4-sulfophenyl) phosphonium hydrogen sulfate. These three materials react together through pseudo-eight-components reaction to generate complex products with four stereocenters that involves ten new bond formations. This synthetic method can be a combination of Knoevenagel and Michael reactions. Download : Download full-size image

Phthalic acid as a green, biodegradable economical and environmentally benign nature catalyst for the one-pot three-component Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives via β-keto esters, aldehyde derivatives and urea/thiourea under thermal and solvent-free conditions and one-pot four-component domino condensation of substituted dihydro-2-oxypyrrole by reaction of dialkyl acetylenedicarboxylate, formaldehyde and amines (aromatic and aliphatic) under ambient temperature with short reaction times and excellent yields is reported. The most benefits this procedure are such as green, biodegradable, inexpensive and non-toxic catalyst, eco-friendly, high catalytic activity, efficient, easily separation with no column chromatographic separation, simple operational procedures, one-pot, excellent yields, environmentally benign nature.