فهرست مطالب negar lashgari

In this study, the application of the Diels-Alder cycloaddition reactions between methyl acrylate and cyclopentadiene has been studied using a silica-supported catalyst with various concentrations of Zn2+ ion (Silica@Zn+2) as Lewis acid catalyst without using the solvent. The effective role of silanol groups in increasing stereoselectivities of products was also studied.

Organic-inorganic hybrid mesoporous materials such as amino functionalized silica (SBA-Pr-NH2) have received considerable attention due to their basic catalytic applications and adsorption functions. In this work, we investigated the efficient role of SBA-Pr-NH2 as a heterogeneous nano catalyst in the synthesis of 9,10-diaryl-7H-benzo[d,e]imidazo[2,1-a]isoquinolin-7-one derivatives. Application of SBA-Pr-NH2 as an eco-friendly and reusable catalyst resulted in reducing reaction time and temperature in this method. The preparation method was developed using a green one-pot three-component reaction of acenaphthoquinone, benzils and ammonium acetate under solvent-free condition. Besides, the synthesis of benzil derivatives as starting material was carried out. The new compounds were characterized by IR, mass, and NMR spectroscopy. The significant merits of this protocol are its simplicity, short reaction times, low reaction temperature, catalyst reusability, and non-chromatographic purification of products. Also, imidazole and benzimidazole moieties represent significant substructures of a wide variety of bioactive compounds and also significant structural motifs in biological systems, natural products, and drugs.

In this research article, ionic liquid modified SBA-15 mesoporous material (SBA-IL) as a recyclable, heterogeneous catalyst efficiently catalyzed the synthesis of pyranonaphthoquinone-fused spirooxindoles through the one-pot three-component reaction of isatin derivatives, activated methylene reagents, and 2-hydroxy-1,4-naphthoquinone. The reactions were performed under microwave irradiation and solvent-free conditions. The synthesized SBA-IL was characterized by SEM, FT-IR, nitrogen adsorption-desorption, and thermogravimetric analyses. Excellent chemical yields, short reaction times, mild reaction condition, easy workup procedures and reusability of catalyst are noteworthy advantages of this protocol.

A simple, efficient, and environmentally friendly method has been developed for the synthesis of a series of tricyclic fused pyrazolopyranopyrimidines via a one-pot three-component reaction of barbituric acids, aromatic aldehydes, and 3-methyl-5-pyrazolone in the presence of SBA-Pr-SO3H. SBA-15 mesoporous silica material functionalized with propyl sulfonic acid groups was used as a heterogeneous Brønsted acid catalyst with hexagonal structure, high surface area, thick walls, and large uniform pores. All reactions were performed under reflux conditions in water in the presence of a catalytic amount of SBA-Pr-SO3H. High yields, mild reaction conditions, short reaction times, and simple work-up procedures are some advantages of this method. The antimicrobial activities of the synthesized compounds were also evaluated and some products exhibited significant antibacterial activities at low concentrations.

the current study, a series of 3,4-dihydro-2-pyridone derivatives were synthesized in a one-pot four-component reaction of Meldrum’s acid, benzaldehyde derivatives, methyl acetoacetate, and ammonium acetate. SiO2-Pr-SO3H was used as an efficient catalyst for the synthesis of the target compounds under solvent-free conditions. The most probable mechanism for this reaction has been discussed. The advantages of this methodology are high product yields, being environmentally benign, short reaction times, and easy handling. Eight 2-pyridinone derivatives were evaluated for their inhibitory activities against Jack bean urease. Molecular docking study of the synthesized compounds was also evaluated. All compounds showed good activities against urease and among them, 4-(4-nitrophenyl)-5-methoxycarbonyl-6-methyl-3,4-dihydropyridone (5a) showed the most potent activity (IC50 = 29.12 µM), more potent than hydroxyurea as the reference drug (IC50 = 100.0 µM). Also, the results from docking studies were in good agreement with those obtained with in vitro assay. According to the docking studies methionine (Met) 637 and nitro phenyl ring cause n-π interaction between lone pair of sulfur atom and π aromatic ring. Moreover, hydrophobic interactions existed between compound 5a and alanine (ALA) 636, ALA 440, and isoleucine 411. The results indicated that the inhibitory activities increased with the increase of electron withdrawing ability of the groups despite a less important role of lipophilicity in increasing the inhibitory activity.

Herein, we prepared a V/SBA-16 catalyst using vanadyl acetylacetonate as a precursor and SBA-16 nanoporous silica as a support via an immobilization technique. The ordered mesoporous structure of catalyst was determined by X-ray diffraction and transmission electron microscopy techniques , and the catalyst was evaluated in the benzene hydroxylation to phenol with hydrogen peroxide (H2O2) as a green oxidant. The effects of three key factors, namely reaction temperature (°C), H2O2 content (mL) and catalyst amount (g) at five levels (“1.68, “1, 0, , .68), and also their interaction on the phenol yield were investigated using response surface methodology combined with central composite design. The high correlation coefficient (R2), i.e., 0.983, showed that the data predicted using RSM were in good agreement with the experimental results. The optimization results also exhibited that high phenol yield (17.09%) was achieved at the optimized values of the operating variables: the reaction temperature of 61 °C, H2O2 content of 1.69 mL and a catalyst amount of 0.1 g. In addition, response surface methodology provides a reliable method for optimizing process variables for benzene hydroxylation to phenol, with the minimum number of experiments.

One-pot multicomponent reaction between isatin, barbituric acid, and 6-amino-1,3-dimethyl uracil was investigated in the presence of sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) and resulted in the formation of spirooxindole dipyrimidines. Spirooxindole unit is found in many natural products and biologically active molecules and 1,4-dihydropyridines are an important class of compounds with interesting biological activities such as vasolidator, antitumor, antidiabetic, bronchodilator and anti-atherosclerotic activities. Excellent yields and short reaction timesare related to the highefficiency of SBA-Pr-SO3H that the reactions take place easily in its nano-pores. Mild reaction conditions and easy work-up procedures are other advantages of this green method.

In this research, a V-SBA-16 catalyst was prepared using SBA-16 nanoporous material as a support and vanadium complex via a reflux method (V-SBA-16). The catalyst was characterized using N2 adsorption–desorption isotherms, X-Ray Diffraction (XRD), Ultraviolet-visible spectroscopy, and transmission electron microscopy. Characterization results showed that the ordered nanoporous structure of the support was retained during the catalyst preparation and did not collapse. The efficiency of catalyst was evaluated for direct oxidation of benzene to phenol at different reaction temperatures (25, 60 and 90 °C). The higher yield and selectivity toward phenol were obtained of 16% and 60%, respectively, at 60 °C.

The recognition of the biologically and environmentally important ions is of great interest in the field of chemical sensors in recent years. The fluorescent sensors as a powerful optical analytical technique for the detection of low level of various analytes such as anions and metal cations have been progressively developed due to the simplicity, cost effective, and selectivity for monitoring specific analytes in various systems. Organic-inorganic hybrid nanomaterials have important advantages as solid chemosensors and various innovative hybrid materials modified by fluorescence molecules were recently prepared. On the other hand, the homogeneous porosity and large surface area of mesoporous silica make it a promising inorganic support. SBA-15 as a two-dimensional hexagonal mesoporous silica material with stable structure, thick walls, tunable pore size, and high specific surface area is a valuable substrate for modification with different organic chelating groups. This review highlights the fluorescent chemosensors for ionic species based on modification of the mesoporous silica SBA-15 with different organic molecules, which have been recently developed from our laboratory.