A green, efficient, and rapid procedure for the synthesis of 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]quinolin-5-one derivatives catalyzed by ammonium acetate

A green, efficient, and rapid procedure for the synthesis of 2-amino-3-cyano-1,4,5,6-tetrahydropyrano[3,2-c]quinolin-5-one derivatives has been developed by one-pot condensation of 4-hydroxyquinolin-2(1H)-one, aldehyde, and malononitrile in the presence of ammonium acetate in EtOH. This method has the advantages of operational simplicity, mild reaction conditions, short reaction time, and little environmental impact.     

Nano crystalline ZnO catalyzed one pot multicomponent reaction for an easy access of fully decorated 4H-pyran scaffolds and its rearrangement to 2-pyridone nucleus in aqueous media

A green and highly efficient protocol has been developed for the synthesis of 4H-pyran scaffolds installing a one-pot three-component coupling reaction of an aldehyde, malononitrile, and a 1,3-diketo compound using nano structured ZnO as the catalyst in aqueous alcoholic medium. A greener method to synthesize 3,4-dihydropyridin-2-one has also been developed by rearranging 4H-pyran derivatives in aqueous medium applying p-TSOH as the right catalyst source. A wide spectrum of functional groups was tolerated in both the developed synthetic protocols with good to excellent yield of the targeted molecules.     

One-pot synthesis of 1,2,4,5-tetrahydro-2,4-dioxobenzo[b][1,4]diazepine and malonamide derivatives using multi-component reactions

In this work, a new series of 1,2,4,5-tetrahydro-2,4-dioxobenzo[b][1,4]diazepine and malonamide derivatives have been synthesized using an aromatic 1,2-diamine, Meldrum's acid, an isocyanide, and an arylidene malononitrile (or an aldehyde and malononitrile instead of an arylidene malononitrile) in CH₂Cl₂ at ambient temperature. Synthesis of 1,2,4,5-tetrahydro-2,4-dioxobenzo[b][1,4]diazepine proceeded via four- and five-component reactions; while the synthesis of malonamide derivatives was performed using five- and six-component reactions. In addition, a new series of the malonamide derivatives have been prepared using an aldehyde, malononitrile, Meldrum's acid, an isocyanide, and two molecules of 1,4-diamine via a six-component reaction. These procedures provide alternative methods to the synthesis of a new series of 1,2,4,5-tetrahydro-2,4-dioxobenzo[b][1,4]diazepine and malonamide derivatives.     

An Efficient,Multicomponent, One‐pot Synthesis of Tetra Substituted Pyrans in Water

A new and environmentally benign multi‐component synthesis of tetra substituted 4H‐pyran derivatives is developed via the one‐pot reaction of an aromatic aldehyde, malononitrile, and 1,3‐diketone in the presence of NaOH with water as the solvent at RT. The reaction is efficient and affords excellent yields of the products.     

A novel and efficient synthesis of pyrazolo[3,4-d]pyrimidine derivatives and the study of their anti-bacterial activity

In this work 4-amino-6-aryl-2-phenyl pyrimidine-5-carbonitrile derivatives were synthesized through a one-pot,three-component reaction of an aldehyde,malononitrile and benzamidine hydrochloride,in the presence of magnetic nano Fe₃O₄ particles as a catalyst under solvent-free conditions.3-Amino-6-aryl- 2-phenylpyrazolo[3,4-d]pyrimidine derivatives were prepared through an efficient and environmentally friendly reaction between 4-amino-6-aryl-2-phenylpyrimidine-5-carbonitrile derivatives and hydrazine hydrate and their antibacterial activity has been evaluated.     

Isocyanide-based multicomponent reactions: synthesis of 3,3-dicyano-N-alkyl-2-arylpropanamide derivatives

A new isocyanide-based multicomponent reaction between an aromatic aldehyde, malononitrile, an isocyanide, and acetic acid efficiently provides 3,3-dicyano-N-alkyl-2-arylpropanamide derivatives in excellent yields in ethanol at 70 °C. This reaction led to the construction of two carbon-carbon bonds and one amide group in a single synthetic step.     

An Efficient Synthesis of 4H-Benzo[g]chromene-5,10-dione Derivatives through Triethylbenzylammonium Chloride Catalyzed Multicomponent Reaction under Solvent-free Conditions

A series of 4‐aryl‐5,10‐dihydro‐4H‐benzo[g]chromene‐5,10‐dione derivatives were synthesized by a three‐component reaction with aromatic aldehyde, 2‐hydroxy‐1,4‐dihydronaphthalene‐1,4‐dione, and malononitrile catalyzed by triethylbenzylammonium chloride under solvent‐free conditions. The novel efficient method has the advantages of environmental friendliness, high yield, simple work‐up and ease of operation.     

Electrocatalytic one pot synthesis of medicinally relevant 4H-benzo[g]chromene and pyrano[2,3-g]chromene scaffold via multicomponent-domino approach

A highly efficient one pot, multicomponent synthesis of 4H-benzo[g]chromene and pyrano[2,3-g]chromene derivatives are reported by electrochemically stimulated condensation of an aromatic aldehyde, malononitrile and some enolizable acidic compounds in ethanol at room temperature under constant current density. By utilizing common electrode materials and a simple constant current protocol, this method is a new alternative to conventional methods.     

The molecular diversity of three-component reactions of 4-dimethylamino- or 4-methoxypyridine with acetylenedicarboxylates and arylidene cyanoacetates

The three-component reactions of 4-dimethylamino- or 4-methoxypyridine with acetylenedicarboxylates and arylidene cyanoacetates showed very interesting molecular diversity. The polysubstituted 1,8,9,9a-tetrahydro-4H-1,4-ethanoquinolizines, 2H-pyran-2,3-dicarboxylates, and buta-1,3-diene-1,2,4-tricarboxylates derivatives can be formed in high yields and with good diastereoselectivity depending on the substrates and reaction conditions.     

Three-component synthesis of 4-amino-2-aryl-2H-pyrimido-[1,2-b][1,3]benzazole-3-carbonitriles and 4H-pyrimido-[2,1-b][1,3]benzazoles in the presence of magnesium oxide and 12-tungstophosphoric acid as catalysts

A simple and convenient approach was suggested for the synthesis of 4-amino-2-aryl-2H-pyrimido[1,2-b][1,3]benzimidazole-3-carbonitriles or -benzothiazole-3-carbonitriles through a three-component reaction of 2-aminobenzimidazole or 2-aminobenzothiazole, aldehyde, and malononitrile in the presence of magnesium oxide (MgO) and 12-tungstophosphoric acid as catalysts. Three-component reactions of aldehyde, β-ketoester, and 2-aminobenzimidazole or 2-aminobenzothiazole with the formation of 4H-pyrimido[2,1-b]benzimidazole or 4H-py-rimido[2,1-b]benzothiazole derivatives, respectively, were also studied. These approaches have the advantage of high yields, rapid and pure course of the reactions, as well as the use of cheap and available catalysts.     

A new approach to the facile synthesis of mono- and disubstituted quinazolin-4(3H)-ones under solvent-free conditions

Quinazolin-4(3H)-one derivatives were synthesized successfully via a one-pot, three component reaction of isatoic anhydride and an orthoester with ammonium acetate or a primary amine catalyzed by silica sulfuric acid under solvent-free conditions. This is the first report on the synthesis of 2-substituted quinazolin-4(3H)-ones by this procedure.     

One-pot synthesis of dihydropyrano[2,3-c]chromenes via a three component coupling of aromatic aldehydes, malononitrile, and 3-hydroxycoumarin catalyzed by nano-structured ZnO in water: a green protocol

An efficient and green protocol for the synthesis of dihydropyrano[2,3-c]chromene derivatives by one-pot, three component coupling reaction of aromatic aldehyde, malononitrile, and 3-hydroxycoumarin has been developed using nano-structured ZnO as the catalyst. The formation of self-assembled organic nanofiber arising from low-molecular-weight molecules has also been performed. The optical properties of the nano-structured organic molecules were studied.     

Synthesis of 3,4-dihydropyridin-2-one derivatives in convergent mode applying bio catalyst vitamin B1 and polymer supported catalyst PEG-SO3H from two different sets of building blocks

Two highly efficient, green protocols have been developed for the synthesis of 3,4-dihydropyridin-2-one derivatives from different starting materials exploring two reaction specific catalysts, vitamin B₁ (VB₁), and PEG-SO₃H. VB₁ catalyzed simple and convenient protocol has been developed for the synthesis of 3,4-dihydropyridin-2-one derivatives by the installation of aldehyde, cyanoacetamide, and 1,3-dicarbonyl compounds. In addition, 3,4-dihydropyridin-2-one derivatives have also been synthesized by simply combining aldehyde, malononitrile, and 1,3-dicarbonyl compounds via the formation of 4H-pyran nucleus and PEG-SO₃H catalyzed one-pot rearrangement.     

A novel four-component synthesis of ethyl 6-amino-4-aryl-5-cyano-2,4-dihydropyrano[2,3-c]pyrazole-3-carboxylates

Ethyl 6-amino-4-aryl-5-cyano-2,4-dihydropyrano[2,3-с]pyrazole-3-carboxylates were synthesized via a four-component reaction of the sodium salt of diethyloxaloacetate, an aromatic aldehyde, hydrazine hydrate, and malononitrile. The products were obtained in moderate to high yields.     

Triethanolamine‐catalyzed expeditious and greener synthesis of 2‐amino‐4H‐chromenes

Triethanolamine (TEOA), an inexpensive and eco‐friendly base, was used to efficiently catalyze the three‐component condensation reaction of heterocyclic/aromatic aldehyde, (α/β)‐naphthol, and malononitrile in water to give the corresponding substituted 2‐amino‐4H‐chromene derivatives with excellent yields.     

Piperazine‐functionalized nickel ferrite nanoparticles as efficient and reusable catalysts for the solvent‐free synthesis of 2‐amino‐4H‐chromenes

Piperazine‐functionalized nickel ferrite (NiFe₂O₄) nanoparticles were synthesized as recoverable heterogeneous base catalysts using a routine method. The synthesized materials were characterized using various spectroscopic techniques such as infrared, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray, thermogravimetry analysis, and vibrating sample magnetometry. Catalytic efficiency was investigated in the synthesis of 2‐amino‐4H‐chromene derivatives via a one‐pot three component reaction of aldehyde and malononitrile with β or α‐naphthol/5‐methyle resorcinol under solvent‐free conditions with good to high yields. This method is operationally simple and has several advantages such as good to high yield, short reaction times, solvent‐free conditions, and easy synthesis. Moreover, the catalyst was recovered easily using an external magnet and reused three times without distinctive loss in catalytic activity.     

Diketene as an alternative substrate for a new Biginelli-like multicomponent reaction: one-pot synthesis of 5-carboxamide substituted 3,4-dihydropyrimidine-2(1H)ones

5-Carboxamide substituted 3,4-dihydropyrimidine-2(1H)one derivatives were synthesized in a simple and efficient method from the one-pot four-component reactions of an aliphatic or aromatic amine, diketene, an aromatic aldehyde and urea or thiourea in the presence of p-toluenesulfonic acid as a catalyst under mild reaction conditions at ambient temperature.     

Silica‐bonded S‐sulfonic Acid as a Recyclable Catalyst for Synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones

2,3‐Dihydroquinazolin‐4(1H)‐one derivatives were synthesized via a one‐pot, three component reaction of isatoic anhydride and an aromatic aldehyde with ammonium acetate or primary amine catalyzed by silica‐bonded S‐sulfonic acid in ethanol at 80°C. The reaction work‐up is simple and the catalyst is easily separated from the products by filtration. The heterogeneous catalyst was recycled for ten runs upon the condensation reaction of isatoic anhydride and 4‐chlorobenzaldehyde with ammonium acetate without losing its catalytic activity.     

An improved synthesis of Biginelli-type compounds via phase-transfer catalysis

3,4-Dihydropyrimidin-2(1H)-one, 3,4-dihydropyrimidin-2(1H)-thione, and 3,4-dihydropyrimidin-2(1H)-imine derivatives were synthesized by modified Biginelli cyclocondensation reaction in a time-efficient manner with near quantitative yields starting from appropriately substituted aromatic aldehyde, β-ketoester and either urea, thiourea or guanidine as constituent synthons using tetra-butyl ammonium bromide (TBAB) as catalyst for the first time.     

Synthesis of hybrid perillyl-4H-pyrans. Cytotoxicity evaluation against hepatocellular carcinoma HepG2/C3A cell line

A series of 15 new hybrid perillyl-4H-pyrans compounds was straightforwardly synthesized by a strategy combining the multicomponent reaction and the copper-catalyzed alkyne-azide cycloaddition (CuAAC). The 2-amino-4H-pyrans-3-carbonitrile containing the alkyne moiety was prepared via multicomponent reaction between 1,3-dicarbonyl, a propargyloxy aromatic aldehyde and malononitrile or ethyl α-cyanoacetate. The alkyne derivative was sequentially reacted with the perillyl azide component through the copper-catalyzed [3+2] Huisgen cycloaddition reaction. The antiproliferative activity of hybrid compounds were evaluated against the human hepatoma HepG2/C3A cell line.