Asparagine functionalized aluminum oxide nanoparticles (Asp-Al 2 O 3) have been prepared by a two... more Asparagine functionalized aluminum oxide nanoparticles (Asp-Al 2 O 3) have been prepared by a two-step procedure involving the grafting of Al 2 O 3 with 3-chloropropyltrimethoxysilane (CPTMS) and subsequent organofunctionalization using asparagine amino acid. It is shown that Asp-Al 2 O 3 exhibits as an active nanocatalyst for the preparation of 2-aminothiazoles is achieved by one-pot reaction of methylcarbonyls, thiourea and iodine. The structure of Asp-Al 2 O 3 was characterized by fourier transform infrared radiation (FT-TR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopic (SEM), and energy-dispersive analysis of X-ray (EDAX) analyses. Advantages of this modified methodology include higher purity and excellent yield of products, greener and cleaner conditions, easy isolation of products and convenient manipulation. Moreover, immobilization of organocatalysts on the Al 2 O 3 surface are stable under the catalytic reaction conditions resulting their efficient reuse.
In the present work, iron oxide nanoparticles (Fe 3 O 4-NPs) were prepared using a chemical copre... more In the present work, iron oxide nanoparticles (Fe 3 O 4-NPs) were prepared using a chemical coprecipitation method. At room temperature, Fe 3 O 4-NPs are put in inter-lamellar space and external surfaces of montmorillonite (MMT) as a supported solid. The MMT@Fe 3 O 4 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA) and Fourier transform infrared spectrophotometry (FT-IR). Then, indeno[1,2-b]indolone derivatives were catalyzed by magnetic MMT@Fe 3 O 4-NPs. MMT@Fe 3 O 4-NPs were found to be a recoverable organocatalyst for the effective synthesis of the indeno[1,2-b] indolone derivatives via one-pot multicomponent cyclocondensation of ninhydrin, 1,3-diketo compound and amine derivatives in water. The significant advantages of this method are excellent yield, mild conditions, eco-friendly catalyst, low expense, and not using an environmentally harmful catalyst or solvent.
A novel magnetically recoverable nanocomposite including Co 3 O 4 /chitosan/H 3 PW 12 O 40 (Co 3 ... more A novel magnetically recoverable nanocomposite including Co 3 O 4 /chitosan/H 3 PW 12 O 40 (Co 3 O 4 /CS/PWA) as a heterogeneous catalyst was prepared using a facile synthetic method and characterized by FT-IR, XRD, SEM, VSM and EDX. A simple, efficient and rapid synthesis of indeno[2ʹ,1ʹ:5,6]pyrido[2,3-d]py-rimidines was accomplished in excellent yields via one-pot three-component reaction of 1,3-dimethyl-6-aminouracil, aryl aldehydes and 1,3-indandione in the presence of amount of Co 3 O 4 /CS/PWA catalyst under ultrasound irradiation. Then, the catalyst was recovered with an external magnet and reused several times without significant loss of reactivity.
An efficient three-component reaction of aromatic aldehydes, 6-aminouracil/ 6-amino-1,3-dimethylu... more An efficient three-component reaction of aromatic aldehydes, 6-aminouracil/ 6-amino-1,3-dimethyluracil and 4-hydroxycoumarin in the presence of a novel heterogeneous catalyst H 3 PMo 12 O 40-immobilized Co 3 O 4 /chitosan led to a synthesis of a new class of pyrimidinedione derivatives under reflux conditions. The magnetically recoverable nanocomposite of Co 3 O 4 /chitosan/H 3 PMo 12 O 40 was fully characterized by Fourier transform-infrared spectrophotometry, scanning electron microscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscopy, vibrating-sample magnetometry and N 2 adsorption-desorption by Brunauer-Emmett-Teller analysis. Results show that Keggin-type 12-molybdophosphoric acid immobilized into the network of the cross-linked chitosan with super-paramagnetic Co 3 O 4 nanoparticles. The present method offers several advantages, such as simple procedure, short reaction times and excellent yields of products. The novelty of the catalyst, high catalytic activity, easy separation from the reaction with an external magnetic field and reusability of the catalyst in six consecutive runs are additional eco-friendly attributes of this catalytic system.
Root canal disinfection is one of the main factors governing success of endodontic therapy. Antim... more Root canal disinfection is one of the main factors governing success of endodontic therapy. Antimicrobial photodynamic therapy (aPDT) is presented as a promising antimicrobial therapy that can eliminate microbiota present in infected root canal systems. In this study, a series of experiments investigated the effects of aPDT on cell viability and biofilm degradation ability of endopathogenic microbiota. Enterococcus faecalis and Pseudomonas aeruginosa strains as the versatile pathogenic microbiota in endodontic infections were used as the tested strains. Curcumin (CUR) and light-emitting diode (LED) were used as the photosensitizer and light source, respectively. The antimicrobial and anti-biofilm effects of CUR-aPDT were assessed by colony forming unit (CFU), and crystal violet assays. CUR-aPDT significantly decreased the CFU/mL count of E. faecalis and P. aeruginosa compared to the control group (P<0.05). The killing percentage of aPDT was achieved 95.0% for E. faecalis and 81.1% for P. aeruginosa. In addition, the biofilm degradation ability of E. faecalis and P. aeruginosa significantly decreased to 41.2% and 30.2%, respectively (P<0.05). According to the results, neither CUR nor LED showed the antimicrobial and anti-biofilm effects when used alone. In conclusion, the results of this study indicated that CUR-aPDT has an appreciable effect on endopathogenic microbiota upon photoactivation.
Ultrasound irradiation was applied for the rapid and clean synthesis of 3-methyl-4-arylmethylene ... more Ultrasound irradiation was applied for the rapid and clean synthesis of 3-methyl-4-arylmethylene isoxazole-5(4H)-ones through condensation of hydroxylamine hydrochloride, ethyl acetoacetate and benzaldehyde derivatives. This methodology was effectively catalyzed by amine functionalized montmorillonite K10 nanoclay (NH 2-MMT). Compared with conventional methods, this protocol has promising features for the reaction response such as shorter reaction times, easier work-up, ease of separation of pure product with high yields and simplicity in the experimental procedure.
Nowadays, biodegradable polymers are attractive candidates to create high-performance and environ... more Nowadays, biodegradable polymers are attractive candidates to create high-performance and environmentally friendly catalytic species. Polymeric materials for catalytic processes must be biocompatible and preferably biodegradable. Sulfonic acid functionalized chitosan (CS-SO3H) was easily prepared by the reaction of chitosan with chlorosulfonic acid. CS-SO3H is found to catalyze the Hantzsch reaction to produce 1,4-dihydropyridines (1,4DHPs) via the condensation reaction of aldehydes, ethyl acetoacetate and ammonium acetate with high efficiency. The use of heterogeneous and biodegradable CS-SO3H makes this synthetic methodology quite simple, more convenient and economically viable compared to homogeneous chitosan catalyzed method. CS-SO3H with nanopore structure, with encapsulated reactants may be applied as a nanoreactor for this chemical reaction. The main advantages of this protocol are the eco-friendly catalyst system, heterogeneous nature, freedom from organic solvents , and ease of the workup procedure. The present method can be used for the green design of heterocyclic compounds, and has potential for biological applications and drug discovery.
Magnetic carbon nanotube-supported imidazolium ionic liquid (CNT-Fe 3 O 4-IL) was synthesized and... more Magnetic carbon nanotube-supported imidazolium ionic liquid (CNT-Fe 3 O 4-IL) was synthesized and investigated using various characterization techniques, including Fourier transform infrared and Raman spectroscopies, X-ray diffraction, vibrating sample magnetometry, scanning and transmission electron microscopies, and thermogravimetric and differential thermal analyses. In order to synthesize the CNT-Fe 3 O 4-IL nanocomposites, Fe 3 O 4-decorated multi-walled CNTs were modified with 1-methyl-3-(3-trimethoxysilylpropyl)-1H-imidazol-3-ium chloride. This catalytic system was found to be a highly stable, active, reusable and solid-phase catalyst for the synthesis of 2-aminothiazoles via the one-pot reaction of ketone, thiourea and N-bromosuccinimide under mild conditions. Immobilized magnetic ionic liquid catalysis combines the advantages of ionic liquid media with magnetic solid support nanomaterials which enables the application of nanotechnology and green chemistry in chemical processes.
An efficient one-pot synthesis of 2-aminothiazoles from methylcarbonyl and thiourea has been deve... more An efficient one-pot synthesis of 2-aminothiazoles from methylcarbonyl and thiourea has been developed using montmorillonite-K10 as a catalyst at 80 °C in DMSO medium. A plausible mechanism is proposed in which a-iodomethyl-carbonyls are formed via methylcarbonyls as raw material using iodine as iodination reagent.
Ultrasound irradiation was applied for the rapid and clean synthesis of 3-methyl-4-arylmethylene ... more Ultrasound irradiation was applied for the rapid and clean synthesis of 3-methyl-4-arylmethylene isoxazole-5(4H)-ones through condensation of hydroxylamine hydrochloride, ethyl acetoacetate and benzaldehyde derivatives. This methodology was effectively catalyzed by amine functionalized montmorillonite K10 nanoclay (NH 2-MMT). Compared with conventional methods, this protocol has promising features for the reaction response such as shorter reaction times, easier work-up, ease of separation of pure product with high yields and simplicity in the experimental procedure.
In the present study, an attempt has been made to synthesize 3-methyl-4-arylmethylene isoxazole-5... more In the present study, an attempt has been made to synthesize 3-methyl-4-arylmethylene isoxazole-5(4H)-one derivatives through sonication of hydroxylamine hydrochloride, ethyl acetoacetate and benzaldehyde derivatives in the presence of imidazole as a novel and effective catalyst in aqueous media. This green reaction under ultrasound irradiation has advantageous compared to conventional procedures in view of its shorter reaction times, high isolated yields, avoidance of using organic solvents, simple experimental procedure and workup and energy conservation. A combination of the advantages of ultrasound irradiation, homogeneous catalyst and aqueous media provides an important methodology for carrying out catalytic transformations.
An efficient and eco-friendly procedure has been developed using nanocrystalline MgAl 2 O 4 with ... more An efficient and eco-friendly procedure has been developed using nanocrystalline MgAl 2 O 4 with specific surface area as catalyst for rapid and an improved synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions in excellent yields. The method has several benefits, such as shorter reaction time, recyclable catalyst and excellent yields.
cycloaddition reactions [12]. Non-symmetrical azines serve as educts for the preparation of fused... more cycloaddition reactions [12]. Non-symmetrical azines serve as educts for the preparation of fused tricyclic heterocy-clic systems by combined intra-intermolecular criss-cross cycloaddition [13]. Many methods have been designed to synthesize azines in the presence of catalysts such as sulfated anatase-titania [14], TiO 2-P 2 O 5 [15], tetrakis (N-methylpyridyl)porphinatoiron(III) pentachloride ([Fe III TMPyP]Cl 5) [16], and triphenylphosphine (PPh 3) [17]. Nanotechnology has gained a considerable importance in the recent times. Tungsten nanoparticles are attractive as functional materials [18] for surface metallization [19, 20]. New applications of tungsten hexachloride (WCl 6) as a cost-effective and widely available alternative would be interesting for us in recent years. To overcome disadvantages of Lewis acids, much effort has been devoted to develop heterogeneous supported catalysts based mont-morillonite K10 (Mont. K10) clay [21-26]. Montmoril-lonite K10 is a hydrophilic clay with a three-layered structure [27] belonging to the group of the smectites with an ideal chemical formula of (Al 2-y Mg y)Si 4 O 10 (OH) 2 ·nH 2 O [28, 29]. Natural occurrence of both Brønsted and Lewis acidic catalytic sites available in montmorillonite clay make it an effective catalyst [30-32]. Mont. K10 with a surface-active inorganic nature can be applied as efficient support for various transition metal salts and/or metal ions [33-38]. Green heterogeneous supports such as montmoril-lonite K10 clay have been widely used as inexpensive and noncorrosive solid acid catalyst in organic synthetic methodology and are gaining considerable importance from an environmental point of view [39, 40]. Montmorillonite K10 has been employed in several composite systems owing to large surface area, strong acidity, good efficiency, environment friendly nature, cation exchange capacity, selectiv-ity, cheapness, regeneration, and mild reaction conditions [41, 42]. We have developed new applications of tungsten Abstract In the present investigation, we have developed a novel technique to prepare azines using nano-WCl 6 loaded on Montmorillonite K10 clay as a highly active catalyst. A variety of aldehydes and ketones were efficiently converted to the corresponding azines using catalytic amounts of nanosized WCl 6 /Mont. K10 under mild conditions. The nanostructures of WCl 6 loaded on Mont. K10 as solid acid catalyst have been prepared by solid dispersion method. The advantages of this catalyst are rapid completion of the reactions, simplicity of performance, lack of pollution and mild and green reaction conditions. The morphologies, structure, and chemical components of parent and modified clay were successfully characterized using SEM, FT-IR, CV, XRD and EDX measurements.
Asparagine functionalized aluminum oxide nanoparticles (Asp-Al 2 O 3) have been prepared by a two... more Asparagine functionalized aluminum oxide nanoparticles (Asp-Al 2 O 3) have been prepared by a two-step procedure involving the grafting of Al 2 O 3 with 3-chloropropyltrimethoxysilane (CPTMS) and subsequent organofunctionalization using asparagine amino acid. It is shown that Asp-Al 2 O 3 exhibits as an active nanocatalyst for the preparation of 2-aminothiazoles is achieved by one-pot reaction of methylcarbonyls, thiourea and iodine. The structure of Asp-Al 2 O 3 was characterized by fourier transform infrared radiation (FT-TR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopic (SEM), and energy-dispersive analysis of X-ray (EDAX) analyses. Advantages of this modified methodology include higher purity and excellent yield of products, greener and cleaner conditions, easy isolation of products and convenient manipulation. Moreover, immobilization of organocatalysts on the Al 2 O 3 surface are stable under the catalytic reaction conditions resulting their efficient reuse.
In the present work, iron oxide nanoparticles (Fe 3 O 4-NPs) were prepared using a chemical copre... more In the present work, iron oxide nanoparticles (Fe 3 O 4-NPs) were prepared using a chemical coprecipitation method. At room temperature, Fe 3 O 4-NPs are put in inter-lamellar space and external surfaces of montmorillonite (MMT) as a supported solid. The MMT@Fe 3 O 4 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA) and Fourier transform infrared spectrophotometry (FT-IR). Then, indeno[1,2-b]indolone derivatives were catalyzed by magnetic MMT@Fe 3 O 4-NPs. MMT@Fe 3 O 4-NPs were found to be a recoverable organocatalyst for the effective synthesis of the indeno[1,2-b] indolone derivatives via one-pot multicomponent cyclocondensation of ninhydrin, 1,3-diketo compound and amine derivatives in water. The significant advantages of this method are excellent yield, mild conditions, eco-friendly catalyst, low expense, and not using an environmentally harmful catalyst or solvent.
A novel magnetically recoverable nanocomposite including Co 3 O 4 /chitosan/H 3 PW 12 O 40 (Co 3 ... more A novel magnetically recoverable nanocomposite including Co 3 O 4 /chitosan/H 3 PW 12 O 40 (Co 3 O 4 /CS/PWA) as a heterogeneous catalyst was prepared using a facile synthetic method and characterized by FT-IR, XRD, SEM, VSM and EDX. A simple, efficient and rapid synthesis of indeno[2ʹ,1ʹ:5,6]pyrido[2,3-d]py-rimidines was accomplished in excellent yields via one-pot three-component reaction of 1,3-dimethyl-6-aminouracil, aryl aldehydes and 1,3-indandione in the presence of amount of Co 3 O 4 /CS/PWA catalyst under ultrasound irradiation. Then, the catalyst was recovered with an external magnet and reused several times without significant loss of reactivity.
An efficient three-component reaction of aromatic aldehydes, 6-aminouracil/ 6-amino-1,3-dimethylu... more An efficient three-component reaction of aromatic aldehydes, 6-aminouracil/ 6-amino-1,3-dimethyluracil and 4-hydroxycoumarin in the presence of a novel heterogeneous catalyst H 3 PMo 12 O 40-immobilized Co 3 O 4 /chitosan led to a synthesis of a new class of pyrimidinedione derivatives under reflux conditions. The magnetically recoverable nanocomposite of Co 3 O 4 /chitosan/H 3 PMo 12 O 40 was fully characterized by Fourier transform-infrared spectrophotometry, scanning electron microscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscopy, vibrating-sample magnetometry and N 2 adsorption-desorption by Brunauer-Emmett-Teller analysis. Results show that Keggin-type 12-molybdophosphoric acid immobilized into the network of the cross-linked chitosan with super-paramagnetic Co 3 O 4 nanoparticles. The present method offers several advantages, such as simple procedure, short reaction times and excellent yields of products. The novelty of the catalyst, high catalytic activity, easy separation from the reaction with an external magnetic field and reusability of the catalyst in six consecutive runs are additional eco-friendly attributes of this catalytic system.
Root canal disinfection is one of the main factors governing success of endodontic therapy. Antim... more Root canal disinfection is one of the main factors governing success of endodontic therapy. Antimicrobial photodynamic therapy (aPDT) is presented as a promising antimicrobial therapy that can eliminate microbiota present in infected root canal systems. In this study, a series of experiments investigated the effects of aPDT on cell viability and biofilm degradation ability of endopathogenic microbiota. Enterococcus faecalis and Pseudomonas aeruginosa strains as the versatile pathogenic microbiota in endodontic infections were used as the tested strains. Curcumin (CUR) and light-emitting diode (LED) were used as the photosensitizer and light source, respectively. The antimicrobial and anti-biofilm effects of CUR-aPDT were assessed by colony forming unit (CFU), and crystal violet assays. CUR-aPDT significantly decreased the CFU/mL count of E. faecalis and P. aeruginosa compared to the control group (P<0.05). The killing percentage of aPDT was achieved 95.0% for E. faecalis and 81.1% for P. aeruginosa. In addition, the biofilm degradation ability of E. faecalis and P. aeruginosa significantly decreased to 41.2% and 30.2%, respectively (P<0.05). According to the results, neither CUR nor LED showed the antimicrobial and anti-biofilm effects when used alone. In conclusion, the results of this study indicated that CUR-aPDT has an appreciable effect on endopathogenic microbiota upon photoactivation.
Ultrasound irradiation was applied for the rapid and clean synthesis of 3-methyl-4-arylmethylene ... more Ultrasound irradiation was applied for the rapid and clean synthesis of 3-methyl-4-arylmethylene isoxazole-5(4H)-ones through condensation of hydroxylamine hydrochloride, ethyl acetoacetate and benzaldehyde derivatives. This methodology was effectively catalyzed by amine functionalized montmorillonite K10 nanoclay (NH 2-MMT). Compared with conventional methods, this protocol has promising features for the reaction response such as shorter reaction times, easier work-up, ease of separation of pure product with high yields and simplicity in the experimental procedure.
Nowadays, biodegradable polymers are attractive candidates to create high-performance and environ... more Nowadays, biodegradable polymers are attractive candidates to create high-performance and environmentally friendly catalytic species. Polymeric materials for catalytic processes must be biocompatible and preferably biodegradable. Sulfonic acid functionalized chitosan (CS-SO3H) was easily prepared by the reaction of chitosan with chlorosulfonic acid. CS-SO3H is found to catalyze the Hantzsch reaction to produce 1,4-dihydropyridines (1,4DHPs) via the condensation reaction of aldehydes, ethyl acetoacetate and ammonium acetate with high efficiency. The use of heterogeneous and biodegradable CS-SO3H makes this synthetic methodology quite simple, more convenient and economically viable compared to homogeneous chitosan catalyzed method. CS-SO3H with nanopore structure, with encapsulated reactants may be applied as a nanoreactor for this chemical reaction. The main advantages of this protocol are the eco-friendly catalyst system, heterogeneous nature, freedom from organic solvents , and ease of the workup procedure. The present method can be used for the green design of heterocyclic compounds, and has potential for biological applications and drug discovery.
Magnetic carbon nanotube-supported imidazolium ionic liquid (CNT-Fe 3 O 4-IL) was synthesized and... more Magnetic carbon nanotube-supported imidazolium ionic liquid (CNT-Fe 3 O 4-IL) was synthesized and investigated using various characterization techniques, including Fourier transform infrared and Raman spectroscopies, X-ray diffraction, vibrating sample magnetometry, scanning and transmission electron microscopies, and thermogravimetric and differential thermal analyses. In order to synthesize the CNT-Fe 3 O 4-IL nanocomposites, Fe 3 O 4-decorated multi-walled CNTs were modified with 1-methyl-3-(3-trimethoxysilylpropyl)-1H-imidazol-3-ium chloride. This catalytic system was found to be a highly stable, active, reusable and solid-phase catalyst for the synthesis of 2-aminothiazoles via the one-pot reaction of ketone, thiourea and N-bromosuccinimide under mild conditions. Immobilized magnetic ionic liquid catalysis combines the advantages of ionic liquid media with magnetic solid support nanomaterials which enables the application of nanotechnology and green chemistry in chemical processes.
An efficient one-pot synthesis of 2-aminothiazoles from methylcarbonyl and thiourea has been deve... more An efficient one-pot synthesis of 2-aminothiazoles from methylcarbonyl and thiourea has been developed using montmorillonite-K10 as a catalyst at 80 °C in DMSO medium. A plausible mechanism is proposed in which a-iodomethyl-carbonyls are formed via methylcarbonyls as raw material using iodine as iodination reagent.
Ultrasound irradiation was applied for the rapid and clean synthesis of 3-methyl-4-arylmethylene ... more Ultrasound irradiation was applied for the rapid and clean synthesis of 3-methyl-4-arylmethylene isoxazole-5(4H)-ones through condensation of hydroxylamine hydrochloride, ethyl acetoacetate and benzaldehyde derivatives. This methodology was effectively catalyzed by amine functionalized montmorillonite K10 nanoclay (NH 2-MMT). Compared with conventional methods, this protocol has promising features for the reaction response such as shorter reaction times, easier work-up, ease of separation of pure product with high yields and simplicity in the experimental procedure.
In the present study, an attempt has been made to synthesize 3-methyl-4-arylmethylene isoxazole-5... more In the present study, an attempt has been made to synthesize 3-methyl-4-arylmethylene isoxazole-5(4H)-one derivatives through sonication of hydroxylamine hydrochloride, ethyl acetoacetate and benzaldehyde derivatives in the presence of imidazole as a novel and effective catalyst in aqueous media. This green reaction under ultrasound irradiation has advantageous compared to conventional procedures in view of its shorter reaction times, high isolated yields, avoidance of using organic solvents, simple experimental procedure and workup and energy conservation. A combination of the advantages of ultrasound irradiation, homogeneous catalyst and aqueous media provides an important methodology for carrying out catalytic transformations.
An efficient and eco-friendly procedure has been developed using nanocrystalline MgAl 2 O 4 with ... more An efficient and eco-friendly procedure has been developed using nanocrystalline MgAl 2 O 4 with specific surface area as catalyst for rapid and an improved synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions in excellent yields. The method has several benefits, such as shorter reaction time, recyclable catalyst and excellent yields.
cycloaddition reactions [12]. Non-symmetrical azines serve as educts for the preparation of fused... more cycloaddition reactions [12]. Non-symmetrical azines serve as educts for the preparation of fused tricyclic heterocy-clic systems by combined intra-intermolecular criss-cross cycloaddition [13]. Many methods have been designed to synthesize azines in the presence of catalysts such as sulfated anatase-titania [14], TiO 2-P 2 O 5 [15], tetrakis (N-methylpyridyl)porphinatoiron(III) pentachloride ([Fe III TMPyP]Cl 5) [16], and triphenylphosphine (PPh 3) [17]. Nanotechnology has gained a considerable importance in the recent times. Tungsten nanoparticles are attractive as functional materials [18] for surface metallization [19, 20]. New applications of tungsten hexachloride (WCl 6) as a cost-effective and widely available alternative would be interesting for us in recent years. To overcome disadvantages of Lewis acids, much effort has been devoted to develop heterogeneous supported catalysts based mont-morillonite K10 (Mont. K10) clay [21-26]. Montmoril-lonite K10 is a hydrophilic clay with a three-layered structure [27] belonging to the group of the smectites with an ideal chemical formula of (Al 2-y Mg y)Si 4 O 10 (OH) 2 ·nH 2 O [28, 29]. Natural occurrence of both Brønsted and Lewis acidic catalytic sites available in montmorillonite clay make it an effective catalyst [30-32]. Mont. K10 with a surface-active inorganic nature can be applied as efficient support for various transition metal salts and/or metal ions [33-38]. Green heterogeneous supports such as montmoril-lonite K10 clay have been widely used as inexpensive and noncorrosive solid acid catalyst in organic synthetic methodology and are gaining considerable importance from an environmental point of view [39, 40]. Montmorillonite K10 has been employed in several composite systems owing to large surface area, strong acidity, good efficiency, environment friendly nature, cation exchange capacity, selectiv-ity, cheapness, regeneration, and mild reaction conditions [41, 42]. We have developed new applications of tungsten Abstract In the present investigation, we have developed a novel technique to prepare azines using nano-WCl 6 loaded on Montmorillonite K10 clay as a highly active catalyst. A variety of aldehydes and ketones were efficiently converted to the corresponding azines using catalytic amounts of nanosized WCl 6 /Mont. K10 under mild conditions. The nanostructures of WCl 6 loaded on Mont. K10 as solid acid catalyst have been prepared by solid dispersion method. The advantages of this catalyst are rapid completion of the reactions, simplicity of performance, lack of pollution and mild and green reaction conditions. The morphologies, structure, and chemical components of parent and modified clay were successfully characterized using SEM, FT-IR, CV, XRD and EDX measurements.
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