Sharif Digital Repository

Palladium nanoparticles immobilized on the magnetic nanoparticles@2-amino-N-(2-aminoethyl) benzamide (MNPs@A-N-AEB.Pd0) have been presented as an efficient, and reusable magnetically heterogeneous catalyst for the C-O coupling reaction, namely Ullmann condensation reactions in an aqueous medium. This heterogeneous catalyst shows superior reactivity for the C-O arylation of different aryl halide (chloride, bromide, and iodide) with phenol derivatives to afford the desired products in good to excellent yields within short reaction time. Moreover, the catalyst can be easily recovered and reused for seven runs without loss of catalytic activity. The catalyst was characterized by several... 

A comprehensive study was carried out for the first time on the acidity of eleven different leaves. After functionalization of the leaves with –SO3H groups, the most acidic one was magnetized using nickel ferrite nanoparticles. This novel, inexpensive, green and biodegradable catalyst showed high activity in the synthesis of pyrazoline and 2-amino nicotinonitriles. Some compounds are new and have never been synthesized before and confirmed by FT-IR, 1H NMR and 13C NMR analysis. All of these compounds possess multiple biological activities. The heterogeneous magnetic catalyst (NiFe2O4-Alnus-SO3H) was characterized by various physicochemical techniques such as FT-IR spectroscopy, field... 

A new and efficient synthesis of pyrimido[4,5-d]pyrimidine-2,4-dione derivatives through the reaction of 6-aminouracils and N,N′-bis(arylmethylidene) arylmethane in the presence of molecular iodine as a readily available and feasible catalyst  

A simple procedure for the synthesis of dipyrazolo[1,5]diazocine-3,8-diones was developed via the one-pot reaction of 3-aminopyrazolone with substituted benzaldehydes in the presence of catalytic p-toluenesulfonic acid (PTSA). © 2018 Elsevier Ltd  

Camosol was isolated from the aerial parts of Salvia eremophula Boiss and full assignments of 1H and 13C-NMR spectral data are presented  

Styrenes are efficiently transformed to thioamides via the Willgerodt- Kindler reaction under microwave irradiation  

This study proposes a computer modeling approach to find the optimal damping coefficients of the viscoelastic ankle-foot prostheses for each specific amputee. A two-dimensional locomotion model was developed for a transtibial amputee and personalized using his body measures and the reference gait pattern of an equivalent able-bodied subject. By employing the forward dynamic simulation, the amputee’s locomotion was synthesized for different prosthetic settings to find the optimal damping coefficients, based on a kinematics and a total work cost function. Results indicated a good agreement between the model predictions and the experimental observations. © 2018, © 2018 RESNA  

This study proposes a computer modeling approach to find the optimal damping coefficients of the viscoelastic ankle-foot prostheses for each specific amputee. A two-dimensional locomotion model was developed for a transtibial amputee and personalized using his body measures and the reference gait pattern of an equivalent able-bodied subject. By employing the forward dynamic simulation, the amputee’s locomotion was synthesized for different prosthetic settings to find the optimal damping coefficients, based on a kinematics and a total work cost function. Results indicated a good agreement between the model predictions and the experimental observations. © 2018, © 2018 RESNA  

Nitriles are efficiently transformed to thiomorpholides via the Willgerodt-Kindler reaction under microwave irradiation in solvent-free conditions  

Herein, an efficient and sustainable one-pot, four-component access to rhodanine-oxindole derivatives is achieved by a reaction between primary amines, carbon disulfide, ethyl chloroacetate, and cyano-substituted alkenyl oxindoles. The reaction was conducted without any harsh conditions as well as exhausting workup in polyethylene glycol (PEG) as a green solvent at room temperature and delivered rhodanine-oxindole products in high yield. This publication is the first easy protocol to be reported for the rapid construction of new rhodanine-oxindole derivatives at room temperature without harsh conditions and via multicomponent reaction. © 2021 Taylor & Francis Group, LLC  

We present a novel pincer ligand based on the pyridine scaffold for functionalizing magnetic GO (graphene oxide). Pincer ligands are known for their great control of coordination spheres in catalysts. GO is used as solid support for immobilizing gold nanoparticles to synthesize a heterogeneous catalyst for reducing nitroarenes. The reduction of nitroarenes to aromatic amines is not only of environmental importance but can be used as a model reaction too. The yields of the reduction reactions are promising. Additionally, the reaction conditions are mild and the catalyst has good recyclability and great stability. The nanocatalyst was monitored and characterized by spectroscopic methods. ©... 

The reactivity of different carboxylate esters for the Fries rearrangements has been investigated in a solvent-free reaction using sulfated zirconia as a solid acid catalyst  

This article presents a failure analysis on a gasoline engine cylinder head made of aluminum alloy, which has been used in passenger cars. During an endurance test, a crack initiated from the interior wall of a hole in the center of the cylinder head and then propagated through the thickness of the cylinder head. The metallurgical examinations are conducted in the crack origin zone. The results show that there are many casting pores due to poor quality of casting in the failed cylinder head which has certainly played a crucial role in initiating the crack. Finite element analysis of the cylinder head is performed to identify the stress components. Modeling of a bolt for the hole shows that... 

An efficient synthesis of novel pentacyclic thiopyrano indole-annulated benzo-δ-sultone derivatives is achieved via intramolecular domino Knoevenagel-hetero-Diels-Alder reaction of 2-formylphenyl (E)-2-phenylethenyl sulfonates and indoline-2-thiones in aqueous medium. The products are formed in good yields with high regio- and stereoselectivity  

Used lubricating oil (ULO) is a heavy mixture of various hydrocarbons and needs to be treated before discharging. Considering ULO nature, it is more favorable to recover lighter hydrocarbon cuts from ULO, which not only improves the whole process economically, but also prevents the emission of hardly decomposable hydrocarbons into the environment. In this research, the potential of pyrolysis method for ULO recovery was studied. Furthermore, graphene nanoplatelets (GNP), γ- Fe2O3 and ZnO nanoparticles were used to improve the kinetics of the process and their impacts on the final product quality were evaluated. Based on the results, adding nanomaterials increased the tendency to produce gas... 

Aryl and alkyl isocyanates have been efficiently converted into symmetrical trisubstituted aryl and alkyl isocyanurates, catalyzed by sodium p-toluenesulfinate on its own or in the presence of tetrabutylammonium iodide (TBAI), in a solvent-free condition. The latter has been shown to have a higher catalytic activity  

In this study the ability of artificial neural network (ANN) in forecasting the daily NASDAQ stock exchange rate was investigated. Several feed forward ANNs that were trained by the back propagation algorithm have been assessed. The methodology used in this study considered the short-term historical stock prices as well as the day of week as inputs. Daily stock exchange rates of NASDAQ from January 28, 2015 to 18 June, 2015 are used to develop a robust model. First 70 days (January 28 to March 7) are selected as training dataset and the last 29 days are used for testing the model prediction ability. Networks for NASDAQ index prediction for two type of input dataset (four prior days and nine... 

The catalytic activity of potassium salts of phthalimide (PPI) and succinimide (PSI), as organonucleophilic catalysts, has been investigated for the cyclotrimerization of isocyanates under solvent-free conditions. PPI showed better catalytic activity in comparison with PSI. Diverse and challenging isocyanates afforded the respective symmetrical isocyanurates in good to quantitative yields in an atom economic reaction without any phase transfer catalyst. © 2005 Bentham Science Publishers Ltd  

Aryl benzylsulfonates undergo so-called pseudo-thia-Fries rearrangement under microwave irradiation. Benzylated phenolic compounds have been obtained with the loss of 'SO2' from the starting materials  

Human society is becoming more intransigent on removing organic dyes from polluted water before discharging to the environment. To fulfill this goal, a magnetic metal-organic framework adsorbent based on functionalized magnetic Fe3O4 nanoparticles and highly water stable UiO-66 with high porosity and sensitivity to the external magnetic field was designed and synthesized via an easy step-by-step self-assembly technique. The synthesized adsorbent magnetic nanoparticles (Fe3O4@UiO-66) were applied to remove organic dyes, i.e., methyl orange (MO) and methylene blue (MB), from a contaminated aqueous solution. The experiments displayed that magnetic Fe3O4@UiO-66 has good adsorption uptake for MO...