In water organic synthesis: Introducing itaconic acid as a recyclable acidic promoter for efficient and scalable synthesis of quinoxaline derivatives at room temperature

Substituted quinoxaline derivatives are traditionally synthesized by co-condensation of various starting materials. Herein, we describe a novel environmentally benign in water synthetic route for the synthesis of structurally and electronically diverse ninety quinoxalines with readily available substituted o-phenylenediamine and 1,2-diketones using cheap and biodegradable itaconic acid as a mild acid promotor in 1 hours. The reaction is performed at room temperature, which proceeds through cyclo-condensation reaction followed by obtaining the aforesaid nitrogen-containing heterocyclic adducts without performing the column chromatography up to 96% total yields. The simplicity, high efficiency, and reusable of the catalyst merits this reaction condition as “green synthesis” which enables it to be useful in synthetic transformations upto gram scale level.     

Magnesium oxide nanotubes: synthesis,characterization and application as efficient recyclable catalyst for pyrazolyl 1,4-dihydropyridine derivatives

Magnesium oxide nanotubes were prepared by electrospinning technique. The nanocatalysts have been characterized by various sophisticated techniques, including XRD, SEM, and TEM. The activities of these NT catalysts are promoting pyrazolyl 1,4-dihydropyridine syntheses have been extensively investigated. Various advantages associated with these protocols simple workup procedure, short reaction times, high yields and reusability of the catalyst.     

Environmentally benign one-pot multicomponent synthesis of 1,4-dihydropyridine derivatives applying montmorillonite K10 as reusable catalyst

Chemistry of Heterocyclic Compounds - Environmentally benign one-pot multicomponent synthesis of different 1,4-dihydropyridine derivatives using montmorillonite K10 has been achieved. The...     

Molecular iodine-catalyzed one-pot synthesis of 4-substituted-1,4-dihydropyridine derivatives via Hantzsch reaction

A simple, inexpensive and efficient one-pot synthesis of 1,4-dihydropyridine derivatives at room temperature using catalytic amount of iodine were reported with excellent product yields. An easy access to various substituted 1,4-dihydropyridine derivatives quantitatively using commercially available iodine as a catalyst.     

Sulfamic acid as a recyclable and green catalyst for rapid and highly efficient synthesis of 2-arylbenzothiazoles in water at room temperature

2-Arylbenzothiazoles have been synthesized in water in good to excellent yield from direct condensation of various aromatic aldehydes with 2-aminothiophenol promoted by catalytic amount of sulfamic acid at room temperature. This method provides a simple, rapid and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small quantity of catalyst and simple work-up procedure.     

Sulfamic acid as a green,reusable catalyst for stepwise,tandem & one-pot solvent-free synthesis of pyrazole derivatives

Sulfamic acid (SA) is a bi-functional, cost-effective and reusable green catalyst for the synthesis of 4- (pyrazol-4-yl)methylenepyrazol-5(4H)-one derivatives by one-pot, three-component condensation of pyrazol-4-carbaxaldehydes, β-ketoesters and phenyl hydrazine (Route-I). In addition to this method, another simple condensation of pyrazol-4-carbaxaldehydes with pyrazolone in the presence of SA under the solvent-free condition in good yield is reported. The merits of these protocols are mild conditions, non-aqueous workup, high yields, easy availability of the catalyst, no chromatographic separation and inexpensive solid acid catalyst. Furthermore, SA could be recycled and reused for five times without losing its catalytic activity.     

Citric acid:An efficient and green catalyst for rapid one pot synthesis of quinoxaline derivatives at room temperature

The condensation of o-phenylenediamines with 1,2-dicarbonyl compounds in the presence of citric acid afforded the corresponding quinoxaline derivatives in higher yields at room temperature in ethanol,and most of the reactions were completed in less than 1 min.     

Silica sulfuric acid (SSA) as a solid acid heterogeneous catalyst for one-pot synthesis of substituted pyrroles under solvent-free conditions at room temperature

A variety of N-substituted pyrroles have been synthesized by reacting γ-diketones with amines, diamines or triamine in the presence of silica sulfuric acid (SSA) at room temperature under solvent-free conditions. The experiment protocol features simple operations, and the products are isolated in high to excellent yields (70-98%).     

Cu-catalyzed one-pot multicomponent approach for the synthesis of symmetric and asymmetric 1,4-dihydropyridine (1,4-DHP) linked 1,2,3-triazole derivatives

Abstract

Synthesis of various symmetric and asymmetric 1,4-DHP linked 1,2,3-triazole derivatives from economical and readily available starting materials via a convenient methodology in a single-pot method using CuSO₄·5H₂O as an efficient catalyst has been reported. The reaction proceeded efficiently under the optimized reaction conditions with excellent functional group compatibility providing the desired products in good yields. The method appears to be an efficient combinatorial strategy for the synthesis of new 1,4-DHP linked triazole derivatives.     

ZnO-beta zeolite mediated simple and efficient method for the one-pot synthesis of quinoxaline derivatives at room temperature

A rapid and an efficient one-pot method for the synthesis of quinoxalines catalysed by ZnO-beta zeolite at room temperature is described. This environmentally benign method provides several advantages over methods that are currently employed such as a simple work-up, mild reaction conditions, good to excellent yields, and a process to recover and reuse the catalyst for several cycles with consistent activity.      

Evaluation of magnetically recyclable nano-Fe3O4 as a green catalyst for the synthesis of mono- and bis-tetrahydro-4H-chromene and mono and bis 1,4-dihydropyridine derivatives

Research on Chemical Intermediates - Magnetically separable Fe3O4 nanoparticles were used as an environmental friendly catalyst for the synthesis of mono- and bis-tetrahydro-4H-chromene and mono-...     

具有生物活性的1,4-二氢吡啶衍生物的水热法合成及结构表征

1,4-二氢吡啶衍生物具有很好的生理活性。在医学上用作心血管疾病的防治保健药物,不仅能治疗肠胃疾病、雷诺氏病、脂肪肝、中毒性肝炎,也有抗衰老、防早熟等作用,还可以用作治疗肺动脉高压和癫痫病的辅助药物[1-2]。近年又发现1,4-二氢吡啶衍生物不但是一类高效的钙拮抗剂,亦是一种绿色饲料添加剂。它的合成通常采用文献报道的Hantzsch法合成[3],即将干燥氨气通入乙酰乙酸乙酯与醛的混合溶液中。该反应时间长、操作复杂,且氨气易对环境造成污染。正因为此,越来越多的化学家和药物学家将有机合成的研究重点放在对环境无污染的绿色合成上。如…     

Cellulose sulfuric acid as a bio-supported and recyclable solid acid catalyst for the one-pot synthesis of 2,4,5-triarylimidazoles under microwave irradiation

Abstract

A simple, rapid, and highly efficient method has been attempted for the three-component condensation of benzil/benzoin, aldehydes, and ammonium acetate under microwave irradiation in the presence of a catalytic amount of bio-supported cellulose sulfuric acid under solvent-free conditions to afford the 2,4,5-triarylimidazole derivatives. The catalyst is easily prepared, inexpensive, separated simply by filtration, gives excellent yield of products with shorter reaction times, and is recyclable several times.     

Revisit to the Biginelli reaction: a novel and recyclable bioglycerol-based sulfonic acid functionalized carbon catalyst for one-pot synthesis of substituted 3,4-dihydropyrimidin-2-(1H)-ones

A simple and efficient synthetic protocol has been developed for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones by using a novel bioglycerol-based sulfonic acid functionalized carbon catalyst, devoid of moisture sensitive metal catalysts and corrosive acidic reagents. The developed method has the advantages of good to excellent yields, short reaction times, operational simplicity, and a recyclable catalyst. The catalyst can be prepared by a simple procedure from inexpensive and readily available glycerol and has been shown to be recoverable and reusable up to four cycles without any loss of activity.     

Four-component,one-pot synthesis of spiropyrazolo pyrimidine derivatives by using recyclable nanocopper ferrite catalyst and antibacterial studies

A simple, efficient, ecofriendly, and cost-effective method has been developed for the synthesis of 16 spiropyrazolo pyrimidine derivatives (5a–5p) by a four-component, one-pot reaction of pyrimidine-2,4,6(1H,3H,5H)-trione, 3-oxo-3-phenylpropanenitrile, hydrazine, and isatins (4a–4f) by using nanocopper ferrite catalyst (20?mol%) in water with excellent yields (73–91%). The isatin with electron-withdrawing groups gave products in high yields (5h and 5p). The present methodology offers an environmentally benign, cost-effective, high-yielding method with recyclable catalyst. The drug likeness or “drugability” of all the synthesized compounds were tested through rule of five (RO5) parameters. Compounds 5f, 5h, 5n, and 5p have shown one RO5 violation each. The compounds were screened for their antibacterial activity against human pathogenic bacteria wherein two of the synthesized compounds were found to possess significant antibacterial activity. Compounds showing RO5 violations had negligible antibacterial activity.     

Ferric hydrogensulphate as a recyclable catalyst for the synthesis of fluorescein derivatives

Polycondensation reactions of phenols with phthalic anhydride were carried out in the presence of ferric hydrogensulphate under melt conditions. The reactions proceeded in short reaction times by using a catalytic amount of Fe(HSO₄)₃ and the corresponding fluorescein derivatives were obtained in high yields. The simplicity, scale-up, along with the use of an inexpensive, non-toxic, recyclable catalyst of an environmentally benign nature, are other remarkable features of the procedure. The absorption and emission properties of these fluorescein derivatives were studied.     

Magnesium ferrichromate nanoparticles: an efficient and recyclable catalyst in the synthesis of pyrano[2,3-c]pyrazole derivatives

Research on Chemical Intermediates - Magnetically separable magnesium ferrichromate nanoparticles (MgFeCrO4 NPs) were synthesized by aqueous combustion synthesis (ACS) using glycine as the fuel....