Sonochemically synthesis of pyrazolones using reusable catalyst CuI nanoparticles that was prepared by sonication

A simple and green process to prepare copper iodide in nano scale via sonication was carried out. Subsequently, this nanoparticles was used as an efficient catalyst for the synthesis of 2-aryl-5-methyl-2,3-dihydro-1H-3-pyrazolones via four-component reaction of hydrazine, ethyl acetoacetate, aldehyde and β-naphthol in water under ultrasound irradiation. The combinatorial synthesis was attained for this procedure with applying ultrasound irradiation while making use of water as green ambient. Simple work-up, excellent yield of products and short reaction times are some of the important features of this protocol. Notably, this catalyst could be recycled and reused for five times without noticeably decreasing the catalytic activity.     

Ultrasound promoted one-pot synthesis of 2-amino-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile scaffolds in aqueous media: A complementary ‘green chemistry’ tool to organic synthesis

A green and simple approach to assembling of 2-amino-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile scaffolds via three-component reaction of kojic acid, malononitrile, and aromatic aldehydes in aqueous media under ultrasound irradiation is described. The combinatorial synthesis was achieved for this methodology with applying ultrasound irradiation while making use of water as green solvent. In comparison to conventional methods, experimental simplicity, good functional group tolerance, excellent yields, short routine, and selectivity without the need for a transition metal or base catalyst are prominent features of this green procedure.     

Ultrasound promoted rapid and green synthesis of 1,8-dioxo-octahydroxanthenes derivatives using nanosized MCM-41-SO3H as a nanoreactor,nanocatalyst in aqueous media

An efficient and green procedure has been developed for the synthesis of 1,8-dioxo-octahydroxanthenes derivatives. The reaction was carried out in water under ultrasound irradiation, using nanosized MCM-41-SO₃H. In this method, several types of aromatic aldehyde, containing electron-withdrawing groups as well as electron-donating groups, were rapidly converted to the corresponding 1,8-dioxo-octahydroxanthenes in good to excellent yields. This novel synthetic method is especially favored because it provides a synergy of the nanosized MCM-41-SO₃H and ultrasound irradiation which offers the advantages of high yields, short reaction times, simplicity and easy workup compared to the conventional methods reported in the literature.     

Ultrasound assisted green synthesis of bis(indol-3-yl)methanes catalyzed by 1-hexenesulphonic acid sodium salt

1-Hexenesulphonic acid sodium salt as catalyst for green synthesis of bis(indol-3-yl)methanes was described. The reaction of indole with various aldehydes in water using ultrasound irradiation at ambient temperature for appropriate time using 1-hexenesulphonic acid sodium salt furnish the desired product in good to excellent yield. Utilization of aqueous medium, simple reaction conditions, isolation, and purification makes this manipulation very interesting from an economic and environmental perspective.     

Catalyst-free sonosynthesis of highly substituted propanamide derivatives in water

A clean, rapid and energy-efficient approach to catalyst-free one-pot synthesis of highly substituted propanamide derivatives in water was developed utilizing of the ultrasonic irradiation. The method has been successful in achieving the green chemistry objective. A catalyst-free operation, an energy efficient protocol using ultrasound irradiation instead of conventional heating or stirring and use of water as a non-hazardous, inexpensive and readily available solvent in the one-step reaction against sequential reaction steps thus combining the features of both economic and environmental advantages.     

A novel and environment-friendly method for preparing dihydropyrano[2,3-c]pyrazoles in water under ultrasound irradiation

A green and convenient approach to the synthesis of dihydropyrano[2,3-c]pyrazoles via four-component reaction of aromatic aldehydes, hydrazine, ethyl acetoacetate and malononitrile in water under ultrasound irradiation is described. This method provides several advantages such as environmental friendliness, shorter reaction time, excellent yields, and simple workup procedure.     

Ultrasound-assisted synthesis of 1,8-dioxo-octahydroxanthene derivatives catalyzed by p-dodecylbenzenesulfonic acid in aqueous media

An efficient and convenient approach to the synthesis of 3,3,6,6-tetramethyl-9-aryl-1,8-dioxo-octahydroxanthene derivatives using p-dodecylbenzenesulfonic acid (DBSA) as the catalyst (10 mol.%) under ultrasound irradiation is described. This method provides several advantages such as environment friendliness, high yields and simple work-up procedure. In addition, water was chosen as a green solvent.     

Solvent-free sonochemical preparation of α-aminophosphonates catalyzed by 1-hexanesulphonic acid sodium salt

1-Hexanesulphonic acid sodium salt was found to be an efficient catalyst for the green synthesis of α-aminophosphonates by the coupling of aldehydes/ketone, an amine and triethyl phosphite under ultrasound irradiation at ambient temperature for appropriate time to furnish the desired product in good to excellent yield under solvent-free condition. This catalyst provides clean conversion; greater selectivity and easy workup make this protocol practical and economically attractive.     

An investigation of lipase catalysed sonochemical synthesis: A review

Ultrasonic irradiation has recently gained attention of researchers for its process intensification in numerous reactions. Earlier ultrasound was known for its application either to deactivate enzyme activity or to disrupt the cell. However, in recent years, practice of ultrasonic irradiation began to emerge as a tool for the activation of the enzymes under mild frequency conditions. The incorporation of ultrasound in any of enzymatic reactions not only increases yield but also accelerates the rate of reaction in the presence of mild conditions with better yield and less side-products. To attain maximum yield, it is crucial to understand the mechanism and effect of sonication on reaction especially for the lipase enzyme. Thus, the influence of ultrasound irradiation on reaction yield for different parameters including temperature, enzyme concentration, mole ratio of substrates, solvents ultrasonic frequency and power was reviewed and discussed. The physical effect of cavitation determined by bubble dynamics and rate of reaction through kinetic modelling also needs to be assessed for complete investigation and scale up of synthesis. Thus, prudish utilisation of ultrasound for enzymatic synthesis can serve better future for sustainable and green chemistry.     

Ultrasound-assisted one-pot synthesis of substituted coumarins catalyzed by poly(4-vinylpyridinium) hydrogen sulfate as an efficient and reusable solid acid catalyst

Poly(4-vinylpyridinium) hydrogen sulfate solid acid was found to be efficient catalyst for synthesis of substituted coumarins via Pechmann reaction using ultrasound irradiation at room temperature and neat condition in high yields with short reaction times. This methodology offers momentous improvements over various options for the synthesis of coumarins with regard to yield of products, simplicity in operation and green aspects by avoiding toxic catalysts and solvents. Further, the catalyst can be reused and recovered for several times.     

Environmentally friendly sonocatalysis promoted preparation of 1-thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H-pyrazoles

An efficient and green synthesis of thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H-pyrazoles via the condensation of chalcones with thiosemicarbazide in ethanol and KOH under ultrasound irradiation is reported. The products were isolated in good yields after short reaction times.     

Simultaneous sonication assistance for the synthesis of tetrahydropyridines and its efficient catalyst ZrP2O7 nanoparticles

In this research, a general synthetic method for the synthesis of tetrahydropyridines were developed using ZrP₂O₇ nanoparticles under ultrasonic irradiations. Firstly by a simple and green process, nano zirconium pyrophosphate was prepared via sonication. Subsequently, this nanoparticle was used as an efficient catalyst for the synthesis of highly functionalized tetrahydropyridines via five-component reaction of aromatic aldehyde, amine and ethyl acetoacetate in ethanol under ultrasound irradiation. The present approach offers several advantages such as high yields, environmentally benign, simple work-up, excellent yield of products, short reaction times as well as recoverability and reusability of the catalyst.     

Potassium sorbate as an efficient and green catalyst for Knoevenagel condensation

Potassium sorbate has been utilized as a novel, efficient and green catalyst for the Knoevenagel condensation of aromatic aldehydes with active methylene compounds to afford substituted ole-fins through the conventional stirring or under ultrasound irradiation. Improvements were observed by carrying out the reactions under ultrasound irradiation. The advantages of this procedure are mild reaction conditions, high yields, cleaner reaction profiles and operational simplicity.     

A facile and efficient multicomponent ultrasound-assisted “on water” synthesis of benzodiazepine ring

Molecular Diversity - A facile and efficient multicomponent synthesis of benzodiazepine ring in water under ultrasound irradiation is reported first time. The current procedure escapes traditional...     

Efficient one-pot three-component synthesis of N-(4-arylthiazol-2-yl) hydrazones in water under ultrasound irradiation

A highly efficient and facile one-pot three-component synthesis of N-(4-arylthiazol-2-yl) hydrazones was carried out in excellent yield without any catalyst in water under ultrasound irradiation.     

Two ultrasonic applications for the synthesis of nanostructured copper oxide (II)

In this paper, we present two aspects of the ultrasonic for the synthesis of CuO (II) nanostructures. In the first ultrasound application, we made a copper tip for an ultrasonic probe transducer and used it for electrolysis and ultrasound irradiation processes. This method is named direct sonoelectrochemistry and compares with conventional electrochemistry. CuO (II) nanostructures are obtained after sintering for both direct sonoelectrochemistry method and conventional electrochemistry method. In the second application of ultrasound, the copper nanostructures were generated by the ultrasound ablation method, and then, the heating process was performed for oxidation. The formation of the copper and CuO (II) nanostructures is confirmed by the powder X-ray diffraction (XRD), the field emission electron microscopy (FESEM), and transmission electron microscopy (TEM). The results show that the direct sonoelectrochemistry method generates CuO (II) nanostructures 4.2 times more than conventional electrochemistry. The crystallite size in the electrochemistry methods and direct sonoelectrochemistry is 28.44 nm and 26.60 nm, respectively. The direct sonoelectrochemistry way is a very flexible method and parameters in electrochemical, ultrasound, and the relationship between them can play an important role in the process of synthesis of nanostructures. The crystallite size in the ultrasound ablation method is 21.13 nm and 25.23 nm for the copper and CuO (II) nanostructures. The most important advantages of this method are green, fast, and high purity of the produced nanostructures.     

Ultrasound mediation for one-pot multi-component synthesis of amidoalkyl naphthols using new magnetic nanoparticles modified by ionic liquids

The ionic liquid 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium acetate was immobilized on the Fe₃O₄ nanoparticles (MNPs-IL-OAc) and used as an efficient new heterogeneous nanocatalyst for the one-pot multi-component synthesis of 1-amidoalkyl-2-naphthols under ultrasound irradiation. The advantages of present combined method are the use of a low scale catalyst, easier work-up procedure, waste-free, green and efficient synthetic entry to excellent yield of products in a high reusability and a short reaction time.     

Effect of ultrasound irradiation on bacterial internalization and bacteria-mediated gene transfer to cancer cells

The present study demonstrates that ultrasound irradiation can facilitate bacteria-mediated gene delivery (bactofection). Escherichia coli modified with avidin were employed as a vehicle for delivery of the green fluorescent protein (GFP) gene, a model heterologous gene, into the breast cancer cell line MCF-7. Avidin-mediated binding of E. coli to MCF-7 cells enhanced the internalization of E. coli by approximately 17%, irrespective of the use of ultrasound irradiation. Furthermore, the use of ultrasound irradiation increased the internalization by approximately 5%, irrespective of the presence of avidin on the E. coli cell surface. The percentages of GFP-expressing MCF-7 cells at 24 h after bactofection were below 0.5% and 2% for the case with only avidin-modification of E. coli cell surface and only ultrasound irradiation, respectively. However, combining avidin modification with the ultrasound treatment increased this value to 8%. Thus, the use of avidin-modified bacteria in conjunction with ultrasound irradiation has potential as an effective strategy for tumor-targeted bactofection.     

Microwave-assisted green synthesis of 4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-1-carbothioamides in water

Rapid, efficient, simple and green procedure for the synthesis of 4,5-dihydro-1H-pyrazole-1-carbothioamides via the multicomponent reaction of aryl aldehydes, acetophenones and thiosemicarbazide in water in the presence of tetrabutylammonium hydroxide under microwave irradiation is reported.     

Introduction of poly(4-vinylpyridinium) perchlorate as a new,efficient, and versatile solid acid catalyst for one-pot synthesis of substituted coumarins under ultrasonic irradiation

Poly(4-vinylpyridinium) perchlorate, is a supported, recyclable, eco-benign catalyst for synthesis of substituted coumarins via Pechmann reaction using ultrasound irradiation at room temperature and neat condition in high yields with short reaction times. The catalyst was studied by FT-IR, X-ray diffraction, scanning electron microscope, thermo-gravimetric and energy dispersion X-ray analyses. All the products were extensively characterized by ¹H NMR, FT-IR, MS and melting point analyses. This methodology offers momentous improvements over various options for the synthesis of coumarins with regard to yield of products, simplicity in operation and green aspects by avoiding toxic catalysts and solvents. Further, the catalyst can be reused and recovered for several times without loss of activity.