Tetrazoles have many interesting futures and applications in drug and energy industries. 5-Substituted 1H-tetrazoles were synthesized via [2+3] cycloaddition reaction of aryl or alkyl nitriles with sodium azide in the presence of Fe3O4@SiO2.SnCl4 as catalyst in DMF under reflux conditions. The catalyst was removed from reaction mixture by an external magnet and was reusable for many times without any appreciable loss of its activity. The Fe3O4@SiO2.SnCl4 promotes synthesis of tetrazole in shorter time than other reported catalysts. The obtained tetrazoles were identified by spectroscopic and physical data such as FT-IR, 1HNMR and melting point. Easy workup and reusability of catalyst are some advantages of this protocol. پرونده مقاله

TiCl2/nano-γ-Al2O3 as a new heterogeneous Lewis acid catalyst was synthesized and characterized by FE-SEM, XRD, FT-IR, EDS, XRF, BET and TGA. N-substituted pyrroles have been synthesized via Paal–Knorr reaction in the presence of TiCl2/nano-γ-Al2O3 at room temperature under solvent-free conditions. پرونده مقاله

Kaolin-SO3H nanoparticles were prepared via reaction of kaolin and chlorosulfonic acid and characterized by FT-IR, XRD, FESEM, TEM, XRF, EDS, BET and TGA. The activity of this green catalyst was probed by the synthesis of aryl diazonium salts as the starting reactant and then, their diazo coupling with 2-naphthol to form azo dyes in a solvent-free medium at room temperature. The work-up of the reaction was easy, and the catalyst was removed from the products by simple filtration. The reaction proceeded in a short time, easy purification technique, high yields, and was environmentally friendly furthering approaches to green chemistry. The products were characterized by FT-IR and NMR spectroscopy. پرونده مقاله

Nano-cellulose with high amount of free OH groups could be used as supporting agents for boron trifluoride (BF3). Nano-BF3/cellulose is a solid acid and a biodegradable catalyst which was prepared via reaction of nano-cellulose and BF3. The structure of this catalyst was studied by FT-IR, FESEM, TEM, XRD, EDS, TGA, XRF and BET. In this research, the synthesis of highly functionalized tetrahydropyridines has been developed via a five-component reaction of aldehyde, amine and ethyl acetoacetate using nano-BF3/cellulose under solvent-free conditions. The structures of obtained products were identified by FTIR, 1H NMR and 13C NMR. Some advantages of this protocol are high to good yields, environmentally benign procedure, easy work-up of reaction and moderate reusability of the catalyst. پرونده مقاله

Ovalbumin, as the major component of egg-white, is a globular, biocompatible, nontoxic and biodegradable phosphoglyco protein. This protein with the molecular weight of 44.5 kDa, contains 385 residues of amino acids with isoelectric point (pI) of 4.5. Many purification procedures have been reported for egg-white proteins such as gel permeation and anion exchange chromatography. In this study, we have reported a new inexpensive protocol using acetic acid and sodium chloride for extraction and purification of egg white nano-ovalbumin. The effective performance of this protein as a biocatalyst was proved through synthesis of N-substituted pyrrole derivatives. This reported innovative biomethodology has some advantages such as less pollution, mild reaction conditions, reusability of biocatalyst and excellent yields. پرونده مقاله

The presence of an imidazole ring in natural products and pharmacologically active compounds has instituted a diverse array of synthetic approaches to these heterocycles. Very recently, we among many others have demonstrated that heterogeneous reagent systems have many advantages such as simple experimental procedures, mild reaction conditions and minimization of chemical wastes as compared to the liquid phase counterparts. Thus, inorganic acidic salts such as Al(HSO4)3, Mg(HSO4)2 and Zr(HSO4)4 could be recommended for above mentioned purposes. Al(HSO4)3 is an efficient, readily available and cheap catalyst for thesynthesis of 1,3-benzo[d]thiazole derivatives by condensation of 2-aminothiophenol and aldehydesunder sonication conditions.This protocol is very simple with easy workup and good to excellent yieldsof products. پرونده مقاله

Kaolin-SO3H as a new solid acid is prepared via reaction of kaolin and chlorosulfonic acid. This natural based catalyst is very inexpensive and easy available. Imidazoles are an important class of heterocycles being the core fragment of different natural products and biological systems such as anti-allergic, anti-inflammatory, analgesic, antifungal, antimycotic, antibiotic, antiulcerative, antibacterial, antitumor and inhibitors of the p38 MAP kinase. A simple, highly versatile and efficient synthesis of 1,2,4,5-tetrasubstituted imidazoles is achieved using Kaolin-SO3H as a catalyst at moderate temperature under solvent free condition. The key advantages of this process are high yields with simple work-up using easy available inexpensive natural based catalyst. پرونده مقاله

In this work, an efficient and green procedure for the synthesis of dihydro-2-oxypyrroles has been developed. One-pot four-component condensation reaction of aniline derivatives (2 mmol), dialkyl acetylene dicarboxylate (1 mmol), and aldehydes ( 1 mmol) was done in ethanol at 65 °C in the presence of nano-Fe3O4@SiO2/SnCl4 as a magnetically reusable heterogeneous acid catalyst. The obtained dihydro-2-oxypyrroles were purified without any chromatography techniques. The structure of obtained pure products was identified by physical properties and spectroscopic data such as FT-IR, 1H NMR, 13C NMR and mass spectroscopy. This protocol consistently has the advantages of excellent yields, short reaction time, simple workup, recyclability of the catalyst up to six runs without appreciable loss of activity. پرونده مقاله

In this study, the nano-SiO2/hexamethylenetetramine as a new basic heterogeneous nanocatalyst was prepared and used for the synthesis of pyranopyrazole via the four-component reaction. Various aldehydes, hydrazine hydrate, ethyl acetoacetate and malononitrile were reacted at room temperature under solvent-free and grinding conditions. The morphology and structure of nano-catalyst were investigated by techniques such as FT-IR spectroscopy, FESEM, TEM, XRD, CHNS elemental analyzer and TGA. The structure of pyranopyrazoles was determined by spectroscopic data of FTIR and NMR. The principal affairs of this procedure are easy work-up, high yields, mild conditions and short reaction times. پرونده مقاله

A bio-based magnetic nano-catalyst (Fe3O4@nano-dextrin/Ti(IV)) was synthesized via the preparation of Fe3O4@nano-dextrinas magnetic support and then its treatment with titanium tetrachloride (TiCl4). The properties of this catalyst were characterized by different kinds of techniques such as FT-IR, FESEM, TEM, ICP, XRF, VSM and TGA. As a first report, the catalytic activity of Fe3O4@nano-dextrin/Ti(IV) was investigated in the synthesisof 2,3-dihydroquinazolin-4(1H)-ones via condensation between 2-aminobenzamide and aldehyde under mild conditions. Good efficiency, a high percentage of product yields, simplicity of operation and easy recovery and reuse of catalyst are some benefits of this protocol. پرونده مقاله

In this research work, Nano-SiO2/Taurine was synthesized and characterized by FT-IR, energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), X-ray diffraction patterns (XRD) ,Thermogravimetric analysis (TGA) and MAP analysis. Nano-SiO2/Taurine has considerable benefits such as simple preparation protocol, simple handling, high acidic property, reusability and high stability. Nano-SiO2/Taurine was used as a catalyst for the synthesis of hexahydroquinolines by the reaction of ethyl acetoacetate, dimedone and ammonium acetate with various aldehydes. These reactions were carried out under solvent-free conditions at 85 °C. The present protocol is simple, eco-friendly and efficient. The hexahydroquinolines were produced at high yields and short reaction times. پرونده مقاله