Convenient and fast synthesis of various chromene pharmaceuticals assisted by highly porous volcanic micro-powder with nanoscale diameter porosity

Effects of morphology and size of nanoscale drug carriers on cellular uptake and internalization process: a review

In the field of targeted drug delivery, the effects of size and morphology of drug nanocarriers are of great importance and need to be discussed in depth. To be concise, among all the various shapes of nanocarriers, rods and tubes with a narrow cross-section are the most preferred shapes for the penetration of a cell membrane. In this regard, several studies have focused on methods to produce nanorods and nanotubes with controlled optimized size and aspect ratio (AR). Additionally, a non-spherical orientation could affect the cellular uptake process while a tangent angle of less than 45° is better at penetrating the membrane, and Ω = 90° is beneficial. Moreover, these nanocarriers show different behaviors when confronting diverse cells whose fields should be investigated in future studies. In this survey, a comprehensive classification based on carrier shape is first submitted. Then, the most commonly used methods for control over the size and shape of the carriers are reviewed. Finally, influential factors on the cellular uptake and internalization processes and related analytical methods for evaluating this process are discussed.

A diselenobis-functionalized magnetic catalyst based on iron oxide/silica nanoparticles suggested for amidation reactions

In this study, a new heterogeneous magnetic catalytic system based on selenium-functionalized iron oxide nanoparticles is presented and suggested for facilitating amide/peptide bonds formation. The prepared nanocatalyst, entitled as “Fe₃O₄/SiO₂-DSBA” (DSBA stands for 2,2′-diselanediylbis benzamide), has been precisely characterized for identifying its physicochemical properties. As the most brilliant point, the catalytic performance of the designed system can be mentioned, where only a small amount of Fe₃O₄/SiO₂-DSBA (0.25 mol%) has resulted in 89% reaction yield, under a mild condition. Also, given high importance of green chemistry, convenient catalyst particles separation from the reaction medium through its paramagnetic property (ca. 30 emu·g⁻¹) should be noticed. This particular property provided a substantial opportunity to recover the catalyst particles and successfully reuse them for at least three successive times. Moreover, due to showing other excellences, such as economic benefits and nontoxicity, the presented catalytic system is recommended to be scaled up and exploited in the industrial applications.

Nanoscale bioconjugates: A review of the structural attributes of drug-loaded nanocarrier conjugates for selective cancer therapy

Nanobioconjugates are nanoscale drug delivery vehicles that have been conjugated to or decorated with biologically active targeting ligands. These targeting ligands can be antibodies, peptides, aptamers, or small molecules such as vitamins or hormones. Most research studies in this field have been devoted to targeting cancer. Moreover, the nanostructures can be designed with an additional level of targeting by being designed to be stimulus-responsive or "smart" by a judicious choice of materials to be incorporated into the hybrid nanostructures. This stimulus could be an acidic pH, raised temperature, enzyme, ultrasound, redox potential, an externally applied magnetic field, or laser irradiation. In this case, the smart capability can increase the accumulation at the tumor site or the on-demand drug release, while the ligand ensures selective binding to the tumor cells. The present review highlights some interesting studies classified according to the nanostructure material. These materials include natural substances (polysaccharides), multi-walled carbon nanotubes (and halloysite nanotubes), metal-organic frameworks and covalent-organic frameworks, metal nanoparticles (gold and silver), and polymeric micelles.

Convenient synthesis of dipeptide structures in solution phase assisted by a thioaza functionalized magnetic nanocatalyst

In this study, a heterogeneous nanocatalyst is presented that is capable to efficiently catalyze the synthetic reactions of amide bond formation between the amino acids. This nanocatalyst which is named Fe₃O₄@SiO₂/TABHA (TABHA stands for thio-aza-bicyclo-hepten amine), was composed of several layers that increased the surface area to be functionalized with 2-aminothiazole rings via Diels-Alder approach. Firstly, various analytic methods such as Fourier-transform infrared (FTIR) and energy-dispersive X-ray (EDX) spectroscopic methods, thermogravimetric analysis (TGA), electron microscopy (EM), and UV-vis diffuse reflectance spectroscopy (UV-DRS) have been used to characterize the desired structure of the Fe₃O₄@SiO₂/TABHA catalyst. Afterward, the application of the presented catalytic system has been studied in the peptide bond formation reactions. Due to the existence of a magnetic core in the structure of the nanocatalyst, the nanoparticles (NPs) could be easily separated from the reaction medium by an external magnet. This special feature has been corroborated by the obtained results from vibrating-sample magnetometer (VSM) analysis that showed 24 emu g^-1 magnetic saturation for the catalytic system. Amazingly, a small amount of Fe₃O₄@SiO₂/TABHA particles (0.2 g) has resulted in ca. 90% efficiency in catalyzing the peptide bond formation at ambient temperature, over 4 h. Also, this nanocatalyst has demonstrated an acceptable recycling ability, where ca. 76% catalytic performance has been observed after four recycles. Due to high convenience in the preparation, application, and recyclization processes, and also because of lower cost than the traditional coupling reagents (like TBTU), the presented catalytic system is recommended for the industrial utilization.

Functionalized hybrid magnetic catalytic systems on micro- and nanoscale utilized in organic synthesis and degradation of dyes

Herein, a concise review of the latest developments in catalytic processes involving organic reactions is presented, focusing on magnetic catalytic systems (MCSs). In recent years, various micro- and nanoscale magnetic catalysts have been prepared through different methods based on optimized reaction conditions and utilized in complex organic synthesis or degradation reactions of pharmaceutical compounds. These biodegradable, biocompatible and eco-benign MCSs have achieved the principles of green chemistry, and thus their usage is highly advocated. In addition, MCSs can shorten the reaction time, effectively accelerate reactions, and significantly upgrade both pharmaceutical synthesis and degradation mechanisms by preventing unwanted side reactions. Moreover, the other significant benefits of MCSs include their convenient magnetic separation, high stability and reusability, inexpensive raw materials, facile preparation routes, and surface functionalization. In this review, our aim is to present at the recent improvements in the structure of versatile MCSs and their characteristics, i.e., magnetization, recyclability, structural stability, turnover number (TON), and turnover frequency (TOF). Concisely, different hybrid and multifunctional MCSs are discussed. Additionally, the applications of MCSs for the synthesis of different pharmaceutical ingredients and degradation of organic wastewater contaminants such as toxic dyes and drugs are demonstrated.

One-pot synthesis of chromenes in the presence of nano-cellulose/Ti(IV)/Fe3O4 as natural-based magnetic nano-catalysts under solvent free conditions

In this study, the preparation of magnetic catalysts of titanium tetrachloride stabilized on nano-cellulose named cellulose/Ti^(IV)/Fe₃O₄ was investigated. Various methods such as XRD, SEM, FT-IR, BET, EDX, TEM, TGA and VSM were used to characterize the catalysts. Then, the identified catalysts were used for the synthesis of various chromene skeletons via reaction of malononitrile, aldehyde and dimedone, 4-hydroxycoumarine or 2-naphthole at 70 °C under solvent free conditions. The spectroscopic methods used to determine the structure of the products include ¹³C NMR, ¹H NMR and FT-IR.

In this study, the preparation of magnetic catalysts of titanium tetrachloride stabilized on nano-cellulose named cellulose/Ti^(IV)/Fe₃O₄ was investigated.

Magnetic nanocatalysts utilized in the synthesis of aromatic pharmaceutical ingredients

This review covers recent developments in nanoscale magnetic catalytic systems and their applications in facilitating organic synthetic reactions of aromatic pharmaceutical ingredients.

Convenient conversion of hazardous nitrobenzene derivatives to aniline analogues by Ag nanoparticles, stabilized on a naturally magnetic pumice/chitosan substrate

Herein, silver nanoparticles (Ag NPs), as an effective catalyst for the reduction process of nitrobenzene derivatives to non-hazardous and useful aniline derivatives, are conveniently synthesized on an inherently magnetic substrate. For this purpose, an efficient combination of volcanic pumice (VP), which is an extremely porous igneous rock, and a chitosan (CTS) polymeric network is prepared and suitably used for the stabilization of the Ag NPs. High magnetic properties of the fabricated Ag@VP/CTS composite, which have been confirmed via vibrating-sample magnetometer (VSM) analysis, are the first and foremost advantage of the introduced catalytic system since it gives us the opportunity to easily separate the particles and perform purification processes. Briefly, higher yields were obtained in the reduction reactions of nitrobenzenes (NBs) under very mild conditions in a short reaction time. Also, along with the natural biocompatible ingredients (VP and CTS) in the structure, excellent recyclability has been observed for the fabricated Ag@VP/CTS catalytic system, which convinces us to do scaling-up and suggests the presented system can be used for industrial applications.

Ultrasound-assisted diversion of nitrobenzene derivatives to their aniline equivalents through a heterogeneous magnetic Ag/Fe3O4-IT nanocomposite catalyst

A heterogeneous magnetic catalytic system is fabricated and suitably applied for the fast and direct conversion of nitrobenzene (NB) derivatives to their aniline forms.