p-TSA-catalyzed facile and efficient one-pot eco-friendly synthesis of novel isoxazolyl amino furo[3,2-c]quinolinone derivatives in aqueous medium

A green and operationally simple approach for the synthesis of novel isoxazolyl amino furo[3,2-c]quinolinone derivatives by a one-pot three-component reaction of 4-amino-3-methyl-5 styrylisoxazoles, aryl glyoxal monohydrates and 4-hydroxy-1-methyl-2-quinolinone using p-TSA as the catalyst in aqueous medium was developed. The protocol proves to be an efficient and an environmentally benign in terms of high yields, operational simplicity, clean reaction profile, compatibility with wide range of substrates, water as a solvent and easy purification.     

Water-acetic acid mediated an efficient one-pot eco-friendly synthesis of novel bis-isoxazolopyrroloquinoline derivatives

An efficient, cost-effective and environmentally benign synthesis of novel tetracyclic bis-isoxazolopyrroloquinoline derivatives has been developed via one-pot four-component reaction of 4-amino-3-methyl-5-styrylisoxazoles, dimedone, aryl glyoxal monohydrates and 5-amino-3-methylisoxazole by employing water as a reaction medium and acetic acid (AcOH) as a green promoter. The advantages of this protocol are environmentally friendly, metal-free, less reaction time, operational simplicity, high yields, broad substrate scope and easy purification. Most significant of all, this method is green.     

Meglumine promoted one-pot,four-component synthesis of pyranopyrazole derivatives

Meglumine, a bio-based chemical, was demonstrated to be a highly efficient and reusable catalyst for the synthesis of a series of pyranopyrazole derivatives via a one-pot, four-component reaction of carbonyl compound or isatin, hydrazine hydrate, malononitrile, and β-keto ester in EtOH–H₂O. The catalyst was found to work extremely for aldehydes, ketones or isatins at room temperature to give the corresponding dihydropyrano[2,3-c]pyrazole or spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives in high yields. The salient features of this new methodology are broad substrate scope, room temperature reaction conditions, short reaction times, high yields, easy work-up process, reusability of catalyst, and the absence of hazardous organic solvents.     

Facile one-pot synthesis of N-difluoromethyl-2-pyridone derivatives

[reaction: see text] A novel one-pot synthesis of N-difluoromethyl-2-pyridones is described. N-(Pyridin-2-yl)acetamide derivatives were excellent precursors for the preparation of N-difluoromethyl-2-pyridone derivatives. Difluoromethylation of 2-acetaminopyridine derivatives was achieved with sodium chlorodifluoroacetate as a difluorocarbene source in the presence of a catalytic amount of 18-crown-6. Subsequent in situ hydrolysis of resultant 1,2-dihydro-2-acetimino-1-difluoromethylpyridines proceeded under mild acidic conditions to afford the corresponding N-difluoromethyl-2-pyridones in moderate to good yields.     

Aqueous microwave-assisted one-pot synthesis of N-substituted rhodanines

Two aqueous, one-pot, microwave-assisted methods for the rapid synthesis of N-substituted rhodanines from amine substrates are described. Alkyl- and benzylamines could be converted into the corresponding rhodanines with an atom-efficient one-pot, three-step protocol based on carbon disulfide and chloroacetic acid in short reaction times and good to excellent yields. An alternative, microwave-assisted one-pot, one-step protocol using bis(carboxymethyl)trithiocarbonate in water was developed for the synthesis of N-arylrhodanines from anilines.     

A sustainable one-pot synthesis of cinnamyl acetate in triacetin

A sustainable one-pot synthesis of cinnamyl acetate from cinnamaldehyde is demonstrated for the first time using immobilized Baker’s yeast and free or immobilized acid as catalysts and triacetin as solvent. Employing the immobilized yeast and Amberlyst-36 allowed full conversion and 91% selectivity for cinnamyl acetate after 96 h at room temperature, and both the catalysts and triacetin were successfully recycled.     

Highly efficient one-pot synthesis of tetrahydropyridines

The combination of aromatic aldehydes, and 1,3-dicarbonyl compounds in the presence of a catalytic amount of poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS] and N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide [TBBDA] leads to the formation of highly substituted tetrahydropyridines. In this way, a series of pharmacologically interesting substituted piperidine derivatives were obtained in moderate to high yields at room temperature.     

A new and versatile one-pot synthesis of indol-2-ones by a novel Ugi-four-component-Heck reaction

A novel one-pot-synthesis of highly substituted indol-2-ones using a combination of Ugi and Heck reaction (U-4CR-Heck) is described. The synthesized indol-2-ones represent an interesting pharmacological scaffold with four potential points of diversity. Thus, this novel reaction-type is amenable to combinatorial high-throughput screening.     

A three component one-pot synthesis of N-amino-2-pyridone derivatives catalyzed by KF-Al2O3

Synthesis of 1,6-diamino-4-phenyl-3,5-dicyano-2-pyridone derivatives via a one-pot, three-component reaction of aryl aldehydes, malononitrile, and cyanoacetic hydrazide at room temperature using KF-Al₂O₃ as a recyclable catalyst have been developed. The reaction proceeds through the initial Knoevenagel condensation between aldehyde and malononitrile in the presence of KF-Al₂O₃ to form the benzylidene derivative which then undergoes Michael addition with cyanoacetic hydrazide followed by intramolecular cyclization of the resulting intermediate to produce the N-amino-2-pyridones in good to excellent yields. The structure of the synthesized compounds were characterized and established on the basis of their spectral data analysis and single-crystal XRD analysis.     

Solvent-free synthesis of ferrocenylimines

The mixing of equimolar quantities of ferrocenylaldehydes and aromatic amines in a solvent-free environment provided excellent yields of ferrocenylimines. After mixing the aldehydes and amines, a melt formed which eventually solidified to the product. An analytically pure sample of the product was obtained by cold recrystallization. 2004 Elsevier Science B.V. All rights reserved.     

Novel synthesis of perfluoroalkylated indolizinylphosphonates via a DIPEA-promoted one-pot process

DIPEA-promoted one-pot synthesis of perfluoroalkylated indolizinylphosphonates by the reaction of pyridines 1, bromomethyl ketones 2 with perfluoroalkynylphosphonates 3 is described. This procedure is compatible with a broad range of functional groups in both pyridines and ketones with good yields. The reaction proceeds through a tandem CN bond formation followed by an intramolecular cyclization.     

A new,convenient and expeditious synthesis of 4-alkyl-5-methyl-1H-pyrazol-3-ols in water through a multicomponent reaction

A new, simple and efficient synthesis of 4-alkyl-5-methyl-1H-pyrazol-3-ols in water by a two-pot four component reaction of ethyl acetoacetate, hydrazine hydrate, aldehyde and ketone in presence K₂CO₃ as the catalyst is described. Use of water as the reaction medium, operational simplicity, mild reaction conditions, application of a cost-effective, nontoxic and easily available catalyst with auto-tandem catalysis, wide substrate scope, easy workup and purification process make the protocol highly attractive.     

A synthesis of spirofuran-indenoquinoxalines via isocyanid-based one-pot four-component reaction

A simple and versatile procedure for the combinatorial synthesis of (Z)-dialkyl-5-(alkylimino)-5Hspiro[ furan-2,11'-indeno[1,2-b]quinoxaline]-3,4-dicarboxylates via the catalyst-free one-pot fourcomponent reaction of ninhydrin, benzene-1,2-diamines, dialkyl acetylenedicarboxylates and isocyanides is described.     

Nickel chloride-catalyzed one-pot three-component synthesis of pyrazolophthalazinyl spirooxindoles

A direct and efficient approach for the preparation of pyrazolophthalazinyl spirooxindoles has been developed through one-pot three-component reaction of easily available isatin, malononitrile or cyanoacetic ester, and phthalhydrazide catalyzed by nickel chloride in polyethylene glycol 600. Desired products were obtained in high to excellent yields using a simple workup procedure.     

A review on multi-component green synthesis of N-containing heterocycles using mixed oxides as heterogeneous catalysts

The use of mixed oxides is a well-appreciated approach in the fields of material science and synthesis, due to remarkable tunable surface properties such as acidic and basic characteristics, oxidation/reduction capabilities, and high agility of lattice oxygen, which makes them ideal choices as heterogeneous catalysts. The activity of the mixed oxides broadly relies on the nature of support and active material used and on the preparation method, calcination temperatures. Wide range of techniques for preparation of mixed oxide materials are adoptable, viz. sol-gel, co-precipitation, wet impregnation, microwave irradiation and hydrothermal methods. Use of mixed oxides as solid catalysts have gained popularity in many valued organic transformations, via alkylation, oxidation, condensation, dehydration, dehydrogenation, cycloaddition and isomerization. Application of mixed oxides in the area of green organic synthesis is a valuable strategy, which contributed significantly to the design of many novel heterocyclic scaffolds. The chemistry of N-heterocycle scaffolds, which generally possess five and six membered rings, is an interesting area for both synthetic and medicinal chemistry research constituting over 60% organics used in various arenas. The position and number of nitrogen atoms in the rings, distinguish them as pyrroles, pyrazoles, imidazoles, triazoles, pyridines and pyramidines classes. In this review, we focus on the scope, importance and versatile applications of mixed metal oxides and their synergetic effects as heterogeneous catalysts in the synthesis of variety of N-heterocyclic derivatives. The scientific aspects of the mixed oxides as catalytic active materials to design efficient synthetic protocols for the organic transformations is also discussed.     

A new green approach for the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one derivatives using task specific acidic ionic liquid[NMP]H_2PO_4

12-Aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one derivatives were synthesized by a convenient and environmentally benign procedure involving multicomponent condensation reactions of substituted aromatic aldehydes with 2,7-dihydroxynaphthalene/2-naphthols/2,6-dihydroxynaphthlene and cyclic 1,3-dicarbonyl compounds in task specific acidic ionic liquid[NMP]H_2PO_4 at 80 ℃.This protocol has proved to be efficient in terms of good yields,operational simplicity,easy workup,recyclability of reaction medium/catalyst,and short reaction time.     

An efficient synthesis of benzodiazepine derivatives via a one-pot,three-component reaction accelerated by a chitosan-supported superparamagnetic iron oxide nanocomposite

This work describes the catalytic ability of Fe₃O₄@chitosan as an environmentally benign and stable composite nanocatalyst for the synthesis of benzodiazepine derivatives starting from o-phenylenediamine, dimedone, and different aldehydes via a one-pot, three-component reaction at room temperature. High-to-excellent yields, easy work-up, reusability of the nanocatalyst, and non-toxicity are some of the advantages of this protocol.     

Water-acetic acid mediated an efficient and eco-friendly protocol for the one-pot synthesis of bis-isoxazolyl amino dihydro-1H-indol-4(5H)-ones under mild reaction conditions

A cost-effective and eco-friendly straightforward synthesis of new bis-isoxazolyl amino dihydro-1H-indol-4(5H)-ones is successfully achieved via one-pot three-component reaction of N-isoxazolyl enaminone, aryl glyoxal monohydrates and 4-amino-3-methyl-5-styrylisoxazoles by using water as a reaction medium and acetic acid (AcOH) as cheap and green promoter. The protocol proves to be an efficient and environmentally benign in terms of high yields, low reaction time, operational simplicity, metal-free and wide substrates scope. Most important of all, this reaction process is green.     

A facile one-pot synthesis of functionalized thiazines in water

An efficient synthesis of thiazines from the three component reactions between dialkyl acetylenedicarboxylates,arylisothio-cyanates and iV-nucleophiles at room temperature in water as the solvent is described.     

A one-pot two-step microwave-assisted synthesis of N1-substituted 5,6-ring-fused 2-pyridones

A fast, versatile and practical one-pot, two-step microwave-assisted protocol for the direct synthesis of N1-substituted 5,6-ring-fused 2-pyridones has been developed. The present method proved to be effective on a series of commercially available aldehydes, ketones and amines and could be profitably exploited in drug-discovery settings for the rapid identification of biologically relevant hit compounds.