Design, synthesis and biological evaluation of benzofuran appended benzothiazepine derivatives as inhibitors of butyrylcholinesterase and antimicrobial agents.

A series of bezofuran appended 1,5-benzothiazepine compounds 7a-v was designed, synthesized and evaluated as cholinesterase inhibitors. The biological assay experiments showed that most of the compounds displayed a clearly selective inhibition for butyrylcholinesterase (BChE), while a weak or no effect towards acetylcholinesterase (AChE) was detected. All analogs exhibited varied BChE inhibitory activity with IC50 value ranging between 1.0 ±â€¯0.01 and 72 ±â€¯2.8 µM when compared with the standard donepezil (IC50, 2.63 ±â€¯0.28 µM). Among the synthesized derivatives, compounds 7l, 7m and 7k exhibited the highest BChE inhibition with IC50 values of 1.0, 1.0 and 1.8 µM, respectively. The results from a Lineweaver-Burk plot indicated a mixed-type inhibition for compound 7l with BChE. In addition, docking studies confirmed the results obtained through in vitro experiments and showed that most potent compounds bind to both the catalytic anionic site (CAS) and peripheral anionic site (PAS) of BChE active site. The synthesized compounds were also evaluated for their in vitro antibacterial and antifungal activities. The results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms and showed high activity against both gram positive and gram negative bacteria and fungi.

Isatin functionalized nanoporous SBA-15 as a selective fluorescent probe for the detection of Hg(II) in water.

A highly ordered mesoporous silica material functionalized with isatin (SBA-Pr-IS) was designed and synthesized. Characterization techniques including XRD, TGA, BET, SEM, and FT-IR were employed to characterize the pore structure, textural properties, microscopic morphology, and molecular composition of grafted organic moieties of SBA-Pr-IS. The successful attachment of the organic moiety (0.34 mmol g-1) without the SBA-15 structure collapsing after the modification steps was confirmed. Fluorescence characterization of SBA-Pr-IS was examined upon addition of a wide variety of cations in aqueous medium and it showed high sensitivity toward Hg2+ ions. During testing in an ion competition experiment, it was observed that the fluorescence changes of the probe were remarkably specific for Hg2+ ions. Furthermore, a good linearity between the fluorescence intensity of this material and the concentration of Hg2+ ions was constructed with a suitable detection limit of 3.7 × 10-6 M. Finally, the applicability of the proposed method was successfully evaluated for the determination of Hg2+ ions in real samples. Therefore, SBA-Pr-IS can be used as an efficient fluorescence probe for Hg2+ ions. Graphical Abstract A novel organic-inorganic hybrid material was designed and synthesized by functionalization of SBA-15 mesoporous silica material with isatin. The evaluation of the sensing ability of SBA-Pr-IS using fluorescence spectroscopy revealed that the SBA-Pr-IS was a selective fluorescent probe for Hg2+ ion in water in the presence of a wide range of metal cations.

A Fluorescent Sensor for Al(III) and Colorimetric Sensor for Fe(III) and Fe(II) Based on a Novel 8-Hydroxyquinoline Derivative.

A novel 8-hydroxyquinoline-based fluorescent and colorimetric chemosensor was designed, synthesized and fully characterized. The sensor showed high selectivity and sensitivity toward Al(3+) over other tested cations in EtOH/H2O (1:99, v/v) medium. The increase in fluorescence intensity was linearly proportional to the concentration of Al(3+) with a detection limit of 7.38 × 10(-6) M. Moreover, the sensor exhibited an obvious color change from yellow to black in the presence of Fe(2+) and Fe(3+) in EtOH/THF (99:1, v/v) solution. The absorbance changes showed a linear response to iron ions with the detection limits of 4.24 × 10(-7) M and 5.60 × 10(-7) M for Fe(2+) and Fe(3+), respectively. Thus, this chemosensor provides a novel approach for selectively recognition of Al(3+), Fe(3+) and Fe(2+) among environmentally relevant metal ions.

2,6-Bis(2-Benzimidazolyl)Pyridine Fluorescent Red-Shifted Sensor for Recognition of Zinc(II) and a Calorimetric Sensor for Iron Ions.

The ability of 2,6-bis(2-benzimidazolyl)pyridine (bbp) as an optical sensor was studied by fluorescence spectroscopy, colorimetric and UV-visible techniques. The fluorescence spectra of bbp demonstrated a red-shifted upon addition of Zn(2+) ion, whereas rest of the cations did not induce any shift. Selectivity of the sensor was examined toward Zn(2+) in the presence of a wide range of cations, as interfering agents, that showed no disruption in its function. In addition, the pH effect was tested on the fluorescence response of bbp; which showed the efficiency of the sensor in a wide pH range. The limit of detection for Zn(2+) was estimated as 2.1 µM. Furthermore, the colorimetric studies were carried out and the observations showed a color change from colorless to purple by the addition of Fe(2+) ion and from colorless to yellow by the addition of Fe(3+). The UV-visible studies were carried out to confirm the colorimetric observations. The color changes occurred when Fe(2+) and Fe(3+) were added to the sensors solution, respectively. The detection limits were calculated as 2.8 × 10(-7) M and 3.5 × 10(-6) M for Fe(2+) and Fe(3+), respectively. Hence, bbp can be used as a dual mode optical sensor for detection of Zn(2+) by fluorescence and discriminately detection of Fe(2+) and Fe(3+) visually.

A Simple Colorimetric Chemosensor for Naked Eye Detection of Cyanide Ion.

A simple cyanide chemosensor tetranitrile compound 1 was designed and synthesized via an efficient method in the presence of nanoporous SBA-Pr-NH2 as the catalyst. The chemosensor exhibited high selectivity and sensitivity for detecting CN¯ among different anions through a visual color change from light yellow to purple. The results confirmed that the chemosensor 1 causes the color of the solution to change depending on the concentration of CN¯. Linear changes of the optical properties of the sensor as a function of the concentrations of CN¯ was proved. The detection limit of 3.07 × 10(-7) M was calculated for CN¯. A simple paper test strip system for the rapid detection of CN¯ was developed. The TD-DFT calculations were carried out to understand the sensing mechanism.

A Single Fluorescent Sensor for Hg(2+) and Discriminately Detection of Cr(3+) and Cr(VI).

An iminocrown ether was synthesized and its fluorescence properties were studied in the presence of a variety of cations and anions in 99 % aqueous medium. The results revealed the interesting ability of the iminocrown ether in discriminately detection of Cr(III) and Cr(VI) ions in addition to detection of Hg(2+) ion. Among various environmentally relevant metal ions, Cr(3+) and Hg(2+) enhanced and quenched the fluorescence emission, respectively and among anions only dichromate ion, Cr(VI), quenched the emission while the rest of ions insignificantly influenced the fluorescence emission. Selectivity of the iminocrown ether was also investigated and proved in the presence of excess of common competing ions. Furthermore, the fluorescence intensity of the iminocrown ether was studied as a function of concentrations of the three ions by performing a titration experiment for each one of them. The detection limits of 5.36 × 10(-8), 2.06 × 10(-6), and 7.49 × 10(-8) mol L(-1) were also calculated for Hg(2+), Cr(3+), and Cr(VI), respectively.

Efficient synthesis of spironaphthopyrano [2,3-d]pyrimidine-5,3'-indolines under solvent-free conditions catalyzed by SBA-Pr-SO3H as a nanoporous acid catalyst.

A green, simple one-pot synthesis of spironaphthopyrano[2,3-d]pyrimidine-5,3'-indoline derivatives by a three-component reaction of isatins, 2-naphthol, and barbituric acids under solvent-free conditions in the presence of SBA-Pr-SO(3)H has been accomplished. Sulfonic acid functionalized SBA-15 (SBA-Pr-SO(3)H) as a heterogeneous nanoporous solid acid catalyst was found to be an efficient and recyclable acid catalyst in this synthesis.

The role of hollow magnetic nanoparticles in drug delivery.

The increasing number of scientific publications focusing on nanomaterials in the biomedical field indicates growing interest from the broader scientific community. Nanomedicine is a modern science, and research continues into the application of nanoscale materials for the therapy and diagnosis of damaged tissues. In this regard, substantial progress has been made in the synthesis of magnetic materials with desired sizes, morphologies, chemical compositions, and surface chemistry. Among these, magnetic iron oxide nanoparticles have demonstrated great promise as unique carriers in the delivery of chemical drugs due to their combinations of hollow structures. Importantly, due to the combination of the ability to respond to an external magnetic field and the rich possibilities of their coatings, magnetic materials are universal tools for the magnetic separation of small molecules, biomolecules, and cells. This review provides an overview of the synthesis and biological applications of hollow magnetic nanoparticles in drug delivery systems.

Recent advances in the application of indoles in multicomponent reactions.

Indoles are some of the most versatile and common nitrogen-based heterocyclic scaffolds and are frequently used in the synthesis of various organic compounds. Indole based compounds are very important among heterocyclic structures due to their biological and pharmaceutical activities. The last decade, in particular, has witnessed considerable activity towards the synthesis of indole derivatives due to the possibilities for the design of polycyclic structures by the incorporation of multiple fused heterocyclic scaffolds in an attempt to achieve promising new heterocycles with chemical and biomedical relevance. In this study, we provide an overview on recent applications of indole in the multicomponent reactions for the synthesis of various heterocyclic compounds during the period of 2012 to 2017.

Efficient Synthesis and Antimicrobial Evaluation of Pyrazolopyranopyrimidines in the Presence of SBA-Pr-SO3H as a Nanoporous Acid Catalyst.

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.

Facile one-pot four-component synthesis of 3,4-dihydro-2-pyridone derivatives: novel urease inhibitor scaffold.

In the current study, a series of 3,4-dihydro-2-pyridone derivatives were synthesized in a one-pot fourcomponent 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.

Synthesis of a Nanostructured Composite: Octakis(1-propyl-1H-1,2,3-triazole-4-yl(methyl 2-chlorobenzoate))octasilsesquioxane via Click Reaction.

Octakis(1-propyl-1H-1,2,3-triazole-4-yl(methyl 2-chlorobenzoate))octasilsesquioxanes as functionalized silsesquioxanes were synthesized via click reaction (copper-catalyzed Huisgen 1,3-dipolar cycloaddition reaction) between azidemoiety functionalized silsesquioxane and prop-2-ynyl 2-chlorobenzoate. The latter one was synthesized via the condensation reaction of propargyl alcohol and 2-chlorobenzoyl chloride in the presence of SBA-Pr-NH(2) (Santa Barbara Amorphous type material) as a nano basic catalyst. This approach provides a simple and convenient route to efficiently functionalize a wide range of new structures on the surface of silsesquioxanes.