Recyclable Medium Research Articles

Aqueous extract of Sea buckthorn berries: A greener and ecofriendly medium for synthesis of pyrazolopyranopyrimidines

Sustainable development and environmental consciousness have become increasingly important, leading to a revolution of industrial processes and organic synthesis methods. The use of organic solvents and their associated emissions has emerged as a significant environmental issue. Consequently, there is a growing emphasis on finding substitutes for volatile solvents and halogenated organic solvents in various synthetic processes. This study focuses on a greener and more eco-friendly approach to synthesizing pyrazolopyrimidine derivatives using sea buckthorn aqueous extract as a sustainable medium. Sea buckthorn berries, rich in phenolic compounds, fatty acids, and vitamins A, C, E, along with high organic acid content, are conducive to multicomponent reactions. Pyrazolyl derivatives are of particular interest due to their role as essential components in various biologically active compounds. Overall, this methodology offers a green and environmentally sustainable alternative to current protocols, with positive implications for both sustainability and economic factors. Additionally, Sea buckthorn berry extract proves to be a recyclable medium, with minimal decrease in product yields upon recycling.

Green synthesis of 3,4-disubstituted isoxazol-5(4H)-one using Gluconic acid aqueous solution as an efficient recyclable medium.

Green synthesis of 3,4-disubstituted isoxazol-5(4H)-one using Gluconic acid aqueous solution as an efficient recyclable medium.

Microwave‐Assisted PEG‐400 Medaited Synthesis of 4,5‐dihydro‐1H‐benzo[g]indazole Derivatives: An Enaminone Approach

AbstractA simple, rapid and conceptually new efficient protocol for the synthesis of 4,5‐dihydro‐1H‐benzo[g]indazole derivatives from novel enaminones prepared via Blaise reaction under catalyst free conditions is reported involving polyethylene glycol (PEG‐400) as an efficient recyclable medium without using any organic co‐solvent or additive by Microwave irridation with 91–95 % yields without chromatography.

A green approach for the catalyst‐free synthesis of imidazole‐bearing pyrazole moiety using PEG‐400 as an efficient recyclable medium as potential anti‐tubercular and anti‐microbial agents

AbstractPolyethylene glycol‐400 (PEG‐400) is a recyclable and rapid reaction medium for synthesizing a new series of 4‐(3‐[substitutedphenyl]‐4,5‐dihydro‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐1H‐imidazoles in two‐step procedures by condensation of 1H‐imidazole‐4‐carbaldehyde and various acetophenones to form chalcones followed by base‐catalyzed cyclization employing phenyl hydrazine in a catalyst‐free approach. The way of projected approach provides easy work‐up, less reaction time, avoids metal‐based and toxic catalysts, high yield, and reduces the use of carcinogenic organic solvents. The synthesized scaffolds have been screened for their anti‐microbial and anti‐tubercular activity against a set of pathogens.

Catalyst-free esterification of high amylose starch with maleic anhydride in 1-butyl-3-methylimidazolium chloride: The effect of amylose content on the degree of MA substitution

The limited reactivity of starch towards maleic anhydride (MA) affords maleate with a low degree of MA substitutions (CC and COOH groups). In this study, we investigated the relationship between the starch structure, controlled by its amylose (AM)/amylopectin (AP) ratio, and the DS of starch maleates using C4[mim]Cl as the recyclable media, and catalyst. The results indicated that starches with varying AM/AP ratio produced maleates with comparable CC groups (DSNMR = 0.06–0.07). Following dissolution, the high amylose (DStitration = 1.17, yield = 69.2 %) and regular starches (DStitration = 1.17; yield = 59.3 %) produced high DStitration maleates (COOH groups) at MA/AGU ratio of 12:1 (80 °C, 10 min). Comparatively, DStitration value of waxy starch maleates (DStitration = 0.88, yield = 59.3 %) was lower than AM-based starches, possibly due to the crosslinking tendency of AP branches consisting of carboxylic end-groups. Interestingly, DStitration value for EHCS (1.17) ranged between its bulk (DSNMR: 0.06) and surface distribution of MA (DSSXPS 1.7); therefore, we considered it reliable for future reference.

Improving antifouling performance for the harvesting of Scenedesmus acuminatus using Fe2O3 nanoparticles incorporated PVC nanocomposite membranes

ABSTRACTMembrane filtration provided a potential solution to get high quality microalgae biomass and recyclable medium. However, the fouling of membrane by microalgae cells and organic matter greatly affects membrane harvesting efficiency. In this study, membrane performance was tested in terms of flux declining and backwashing recovery for microalgal harvesting. Compared with the unmodified poly(vinyl chloride) (PVC) membrane, the membrane with 1.0% Fe2O3 incorporation had a 66% increase in average flux, reaching 138 L m− h−1. Foulants on the membrane surface were characterized using attenuated total reflection‐Fourier transform infrared (ATR‐FTIR) and confocal laser scanning microscope (CLSM), as well as sodium hydroxide extraction followed by total organic carbon (TOC) quantification and fluorescence excitation–emission matrix (FEEM) identification of organic components. FEEM and TOC analysis of the extracted foulants revealed that the surface of 1.0% Fe2O3 incorporated membrane had less fouling than the unmodified PVC membrane, which may be attributed to its hydrophilicity after Fe2O3 incorporation. CLSM analysis and ATR‐FTIR analysis of the fouled membrane surface further revealed that the protein substance on the 1.0% Fe2O3 incorporated PVC membrane was lower than those in the unmodified membrane, which further confirmed the enhanced antifouling performance of the 1.0% Fe2O3 incorporated PVC membrane. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47685.

Cp*RhIII ]/Ionic Liquid as a Highly Efficient and Recyclable Catalytic Medium for C-H Amidation.

A [Cp*RhIII ]-catalyzed direct C-H amidation is carried out in ionic liquid. Both C(sp2 )-H bonds of (hetero)arenes and alkenes and unactivated C(sp3 )-H bonds can be easily amidated with high functional-group tolerance and excellent yields under these conditions. Notably, using [Cp*RhIII ]/[BMIM]BF4 (BMIM=1-butyl-3-methylimidazolium) as the green and recyclable medium is environmentally benign, in light of characteristics such as the reusability of the expensive rhodium catalyst, avoidance of highly toxic organic solvents, and mild reaction conditions, as well as a short reaction time.

A Simple Procedure for the One Pot Synthesis of Ascorbic Acid As Efficiency And Recyclable Media

A Simple Procedure for the One Pot Synthesis of Ascorbic Acid As Efficiency And Recyclable Media

Concentrated Aqueous Sodium Tosylate as Green Medium for Alkene Oxidation and Nucleophilic Substitution Reactions.

A hydrotropic solution of highly concentrated sodium tosylate (NaOTs) can be used as a recyclable medium for the environmentally benign oxidation of conjugated alkenes with H2O2. Both uncatalyzed and metal-catalyzed reactions provided the corresponding oxidation products in higher yields than in pure water or many common organic solvents.

Magnetic Ugi-functionalized graphene oxide complexed with copper nanoparticles: Efficient catalyst toward Ullman coupling reaction in deep eutectic solvents

Herein, we report the direct synthesis of carboxamide-functionalized graphene oxide (carboxamide-f-GO) for the development of new nanocatalysts, with highly dispersed particles, through covalent functionalization with a facile and direct strategy. This surface functionalization was carried out through a one-pot sequential four-component Ugi reaction. Subsequently, the Ugi-ligand decorated on the surface of the graphene oxide sheets coordinated with copper nanoparticles (Cu NPs) and finally covered with magnetic nanoparticles. The synthesized nanocatalyst was characterized by Fourier transform infrared (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), thermogravimetric analysis (TGA) and atomic force microscopy (AFM). The carboxamido nitrogen in Ugi-ligand showed high affinity toward complexation with Cu NPs and has a profound effect on the reactivity of the copper center in this nanocatalyst. The catalytic activity of nanocatalyst was investigated in Ullmann cross-coupling reaction for practical and direct access to corresponding N-aryl amines in a deep eutectic solvent as a green and recyclable media. The results showed the capability of this designed catalytic system through N-arylation of N-heterocycles and aniline derivatives with high yields in short reaction times. In addition, both of the nanocatalyst and deep eutectic solvent were easily recovered and reused for five consecutive runs.

Facile Synthesis of 7-Aryl-benzo[h]tetrazolo[5,1-b]quinazoline-5,6-dione Fused Polycyclic Compounds by Using a Novel Magnetic Polyurethane Catalyst

ABSTRACTNovel Brönsted acid functionalized magnetic polymeric nanocomposite, Ba0.5Sr0.5Fe12O19@PU-SO3H, has been successfully synthesized and characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) techniques. The catalytic activity of the nanocomposite was tested in the regioselective synthesis of 7-aryl-benzo[h]tetrazolo [5,1-b] quinazoline-5,6-diones in an eco-friendly and recyclable media, deep eutectic solvent (DES), based on choline chloride and urea. This novel method offers several advantages, such as high yields, short reaction time, environmentally friendly reaction media, easy isolation of the product, and also offers an easy method for the synthesis of nanocatalysts. The catalyst was readily recycled by the use of an external magnetic field and could be reused 6 times without significant loss of activity or mass. DES as one of the most promising environmentally benign and cost-effective alternatives to conventional ionic liquids and volatile organic solvents was recovered from the aqueous filtrate by evaporating the water under vacuum. The recycled DES was used up to 4 runs without any loss in activity.

Ultrasonic-assisted environmentally-friendly synergetic synthesis of nitroaromatic compounds in core/shell nanoreactor: A green protocol

An efficient sonochemical protocol for the nitration of aromatic compounds was described in the presence of a catalytic amount of sulfuric acid-functionalized silica-based core/shell magnetic nanocomposite at room temperature in an eco-friendly and recyclable media, deep eutectic solvent (DES), based on choline chloride and urea. The particle size, morphology and elemental analysis of the core/shell nanocatalyst were carried out by TEM, SEM, EDX and XRD analyses. The nanocatalyst and DES were easily recovered from the reaction mixture quantitatively and reused several times.

Diisopropylethylammonium acetate (DIPEAc): An efficient and recyclable catalyst for the rapid synthesis of 5-substituted-1H-tetrazoles

ABSTRACTA simple and efficient protocol developed for the synthesis of 5-substituted 1H-tetrazole derivatives through [2+3] cycloaddition reaction between benzonitriles and sodium azide using diisopropylethylammonium acetate as a recyclable reaction medium is described. The reactions proceed well at 80 °C and provide the corresponding tetrazoles in good to excellent yields (up to 94% yield). Developed method has notable advantages, such as simple and mild conditions, easy workup, reusability with consistent catalytic activity, and safer alternative to hazardous, corrosive conventional Lewis acid catalysts.

Novel biocompatible glucose-based deep eutectic solvent as recyclable medium and promoter for expedient multicomponent green synthesis of diverse three and four substituted pyrazole-4-carbonitrile derivatives

A novel biocompatible glucose-based deep eutectic solvent (DES) is reported for the first time in the multicomponent synthesis of diverse three and four substituted pyrazole-4-carbonitrile derivatives under catalyst-free condition without using any harmful organic solvent even for purification of the products. The desired products were obtained with high degree of diversity from the reaction of malononitrile, aromatic aldehydes and various hydrazine derivatives as nitrogen source at room temperature within short reaction times and good to excellent product yields. The deep eutectic solvent was also recycled and reused at least four times with only a slight loss of efficiency. A plausible mechanism was also proposed indicating the role of DES hydrogen bonding in the reaction promotion.

One-pot, four-component synthesis of novel biologically important indeno[2,3-b]quinoxaline]-3-carbonitriles in fluoro-alcohols under ultrasound irradiation

We have reported trifluoroethanol (TFE) as an efficient and recyclable medium in promoting one-pot, four-component synthesis of biologically and pharmacologically important spiropyrans and spiroquinoxalines from condensation of malononitrile or ethyl 2-cyanoacetate, ninhydrin, 1,2-phenylenediamine, 1,3-dicarbonyl compounds and 1- or 2-naphthol or naphthylamine under refluxing or ultrasound irradiation at room temperature in good yields. This new protocol employs TFE, which is a green, recyclable, and inexpensive solvent. The best result was obtained in TFE, 8 min, 96% yield under ultrasound irradiation at room temperature.

Ultrasonic treatment of CoFe2O4@B2O3-SiO2 as a new hybrid magnetic composite nanostructure and catalytic application in the synthesis of dihydroquinazolinones

New hybrid magnetic composite nanostructure are prepared via ultrasonic treatment by glass-ceramic method, characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), energy-dispersive X-ray (EDX), element distribution image (EDX mapping), thermal gravimetric analysis (TGA)/differential thermal analysis (DTA) and N2 adsorption-desorption by Brunauer–Emmett-Teller (BET) analyses. Then, the catalytic activity of the prepared CoFe2O4@B2O3-SiO2 nanoparticles was tested in the synthesis of 2-substituted-3-(phenylamino)-dihydroquinazolin-4(1H)-ones in deep eutectic solvent (DES) based on choline chloride as an eco-friendly and recyclable media. This novel protocol offers several advantages such as high yields (70–93%), short reaction times (10–20min), environmentally-friendly reaction media, easily isolation of the products, simple preparation and recoverability of the nanocatalysts (at least 5 times), recyclability of the solvents from the reaction mixture without use of hazardous volatile organic solvent. The catalyst was readily recycled by the use of an external magnetic field and could be reused several times without significant loss of activity or mass. The saturation magnetization of CoFe2O4@B2O3-SiO2 nanoparticles was 8.97emug−1. Their average size distribution was about 12.5nm. DES was a mixture of choline chloride and urea that was recovered from the filtrate by evaporating the water under vacuum.

An efficient nickel chloride catalyzed multi-component condensation of indole with carbonyl compounds in PEG-400 as a green medium at ambient conditions

Bis (indolyl) methane derivatives were efficiently synthesized by the condensation reaction of various aromatic aldehydes and indole in presence of nickel chloride as a Lewis acid catalyst in PEG-400 as a recyclable green solvent at room temperature. The use of PEG-400 and nickel chloride offers improvements for the synthesis of bis (indoyl) methanes with regard to the yield of products, short reaction times and green aspects utilizing recyclable and non volatile medium and avoiding any volatile and hazardous organic solvent.

Synthesis of Aryl 4H-3,1-benzoxazin-4-ones from 2-Aminobenzoic Acid and Arylaldehydes Using PEG-400 as an Efficient and Recyclable Reaction Medium

Synthesis of Aryl 4H-3,1-benzoxazin-4-ones from 2-Aminobenzoic Acid and Arylaldehydes Using PEG-400 as an Efficient and Recyclable Reaction Medium

PEG-400 as an efficient and recyclable reaction medium for the synthesis of 2-aryl-2-methyl-4,5-diphenyl-2,3- dihydro-2H-imidazoles

ABSTRACTA productive natural method has been produced for the synthesis of 2-aryl-2-methyl-4,5-diphenyl-2,3-dihydro-2H-imidazoles in great yields under catalyst free-conditions utilizing polyethylene glycol (PEG-400) as a green reaction medium. The highlights of this new method are shorter reaction times, good yields, room temperature, and use of nontoxic, inexpensive, and recyclable PEG-400.

Ru(ii)/PEG-400 as a highly efficient and recyclable catalytic media for annulation and olefination reactions via C–H bond activation

In this report synthesis of isoquinolinones, isocoumarins, and N-methyl isoquinolinones and olefination of Weinreb amides by C–H bond activation using Ru(ii)/PEG-400 as green and recyclable media are documented.