Facile One-Pot Conversion of (poly)phenols to Diverse (hetero)aryl Compounds by Suzuki Coupling Reaction: A Modified Approach for the Synthesis of Coumarin- and Equol-Based Compounds as Potential Antioxidants.

A series of 16 (hetero)aryl compounds based on coumarin and equol has been efficiently synthesized by exploring the palladium-catalyzed Suzuki cross-coupling reactions. Polyphenol based on coumarin (4-methyl-7-hydroxy coumarin) was initially converted to corresponding coumarin imidazylate and then subjected to Suzuki coupling reaction with 4-methoxyphenylboronic acid to obtain the coupled product. This modified approach was later developed into a one-pot methodology by directly reacting the polyphenol with 1,1-sulfonyldiimidazole (SDI) and boronic acid in situ to obtain the Suzuki coupled product in one step.

Recent Developments on the Synthesis of Oxygen- and Sulfur-containing Heterocycles and their Derivatives under Visible Light Induced Reactions.

Visible-light-mediated reactions have recently emerged as a powerful strategy for the synthesis of diverse organic molecules under mild reaction conditions. Usually, the reactions are performed at room temperature and thus sensitive functional groups remain unaffected. Thus, this protocol has received intense interest from academia as well as industries.

NMI-SOCl-Mediated Amide Bond Formation: Facile Synthesis of Some Dihydrotriazolopyrimidine Amide Derivatives as Potential Anti-Inflammatory and Anti-Tubercular Agents.

Facile access to some novel biologically relevant dihydrotriazolopyrimidine carboxylic acid-derived amide analogues using NMI/SOCl, and aromatic and aliphatic primary and secondary amines, is reported herein. The role of -methylimidazole (NMI) as the base and sulfuryl chloride (SOCl) as the coupling reagent has been effectively realized in accessing these molecules in good to excellent yields. The feasibility of the developed protocol has also been extended to the gram-scale synthesis of -benzylbenzamide in a 75% yield from benzoic acid and benzyl amine.

Visible-Light-Triggered Synthesis of -α-Ketoacylated Sulfoximines by Denitrogenative and Oxidative Functionalization of Vinyl Azides.

We have introduced a sulfoximidation reaction initiated by visible light between α-phenyl vinyl azides and NH-sulfoximines. The cost-effective and readily accessible hypervalent iodine reagent (PIDA) easily promoted the oxidative sulfoximidation process to afford -α-ketoacylated sulfoximines in good to high yields, involving the formation of two new C-O bonds and one C-N bond. Additionally, the protocol offers noteworthy advantages, including its metal-free and photocatalyst-free reaction and its broad substrate compatibility.

Bioinspired Pyrano[2,3-]chromen-8-ones: Ring C-Opened Analogues of Calanolide A: Synthesis and Anti-HIV-1 Evaluation.

We have designed and synthesized a series of bioinspired pyrano[2,3-]coumarin-based Calanolide A analogs with anti-HIV activity. The design of these new calanolide analogs involved incorporating nitrogen heterocycles or aromatic groups in lieu of ring C, effectively mimicking and preserving their bioactive properties. Three directions for the synthesis were explored: reaction of 5-hydroxy-2,2-dimethyl-10-propyl-2,8-pyrano[2,3-]chromen-8-one with (i) 1,2,4-triazines, (ii) sulfonylation followed by Suzuki cross-coupling with (het)aryl boronic acids, and (iii) aminomethylation by Mannich reaction.

Visible-Light-Promoted Metal- and Photocatalyst-Free Reactions between Arylglyoxylic Acids and Tetraalkylthiuram Disulfides: Synthesis of α-Ketoamides.

A convenient and new synthetic approach has been developed for the oxidative cross-coupling of the C-N bond through the reaction between arylglyoxylic acids and tetraalkylthiuram disulfides. The reaction proceeds under ambient air at room temperature in the presence of visible light. This reaction offers a metal-, base-, photocatalyst-, and solvent-free synthesis of various α-ketoamides with moderate to excellent yields via the radical pathway.

Mechanosynthesis of Polyureas and Studies of Their Responses to Anions.

Polyureas (PUs) have already found wide practical applications, and various methods of their synthesis have been reported. In this manuscript, we wished to report the very first mechanochemical approach towards aromatic PUs via reactions between isomeric 2,2'-, 3,3'-, and 4,4'-diaminobiphenyls and triphosgene under solvent-free conditions following ball-milling. By using this synthetic approach, both PUs and azomethine-capped Pus were obtained.

Recent Trends in the Antidiabetic Prominence of Natural and Synthetic Analogues of Aurones.

Natural products are a boundless source for the development of pharmaceutical agents against a wide range of human diseases. Accordingly, naturally occurring aurones possess various biological benefits, such as anticancer, antioxidant, antimicrobial, antidiabetic, anti-inflammatory, antiviral and neuroprotective effects. In addition, various studies have revealed that aurones are potential templates for the regulation of diabetes mellitus and its associated complications.

Structural and Synthetic Aspects of Small Ring Oxa- and Aza-Heterocyclic Ring Systems as Antiviral Activities.

Antiviral properties of different oxa- and aza-heterocycles are identified and properly correlated with their structural features and discussed in this review article. The primary objective is to explore the activity of such ring systems as antiviral agents, as well as their synthetic routes and biological significance. Eventually, the (SAR) of the heterocyclic compounds, along with their salient characteristics are exhibited to build a suitable platform for medicinal chemists and biotechnologists.

Evaluation of Anti-Inflammatory and Anti-Tubercular Activity of 4-Methyl-7-Substituted Coumarin Hybrids and Their Structure Activity Relationships.

Four sets of previously synthesized 4-methyl-7-substituted coumarin derivatives were screened for their in vitro anti-inflammatory and anti-tubercular activities. The anti-inflammatory potential of -, -, -, and - synthesized compounds was evaluated by an anti-denaturation assay using diclofenac sodium as the reference standard. Evaluation of the anti-tuberculous activity of the mentioned compounds was performed by the Resazurin test method against four different TB strains using rifampicin and isoniazid as reference drugs.

Polymers and Polymer-Based Materials for the Detection of (Nitro-)explosives.

Methods for the remote detection of warfare agents and explosives have been in high demand in recent times. Among the several detection methods, fluorescence methods appear to be more convenient due to their low cost, simple operation, fast response time, and naked-eye-visible sensory response. For fluorescence methods, a large variety of fluorescent materials, such as small-molecule-based fluorophores, aggregation-induced emission fluorophores/materials, and supramolecular systems, have been reported in the literature.

Cytotoxic and Infection-Controlled Investigations of Novel Dihydropyridine Hybrids: An Efficient Synthesis and Molecular-Docking Studies.

A sequence of novel 1,4-dihydropyridines (DHP) and their hybrids was developed using a multicomponent strategy under environmentally benign conditions. In addition, computational studies were performed, and the ligand-protein interactions calculated in different bacteria and two fungal strains. Para-hydroxy-linked DHP () showed the best binding energies of 3.

Positively Charged Semiconductor Conjugated Polymer Nanomaterials with Photothermal Activity for Antibacterial and Antibiofilm Activities and .

Biofilm infections are associated with most human bacterial infections and are prone to bacterial multidrug resistance. There is an urgent need to develop an alternative approach to antibacterial and antibiofilm agents. Herein, two positively charged semiconductor conjugated polymer nanoparticles (SPPD and SPND) were prepared for additive antibacterial and antibiofilm activities with the aid of positive charge and photothermal therapy (PTT).

Magnetic FeO nanoparticles loaded guava leaves powder impregnated into calcium alginate hydrogel beads (FeO-GLP@CAB) for efficient removal of methylene blue dye from aqueous environment: Synthesis, characterization, and its adsorption performance.

In the present work, a novel FeO-GLP@CAB was successfully synthesized via a co-precipitation procedure and applied for the removal of methylene blue (MB) from aqueous environment. The structural and physicochemical characteristics of the as-prepared materials were explored using a variety of characterization methods, including pH, XRD, VSM, FE-SEM/EDX, BJH/BET, and FTIR. The effects of several experimental factors on the uptake of MB using FeO-GLP@CAB were examined through batch experiments.

One-pot Synthesis and Photophysical Studies of Α-cycloamino-substituted 5-aryl-2,2'-bipyridines.

A series of α-cycloamine substituted 2,2'-bipyridines 3ae'-3ce' was obtained via the one-pot approach based on ipso-substitution of a cyano-group in 1,2,4-triazines, followed by aza-Diels-Alder reaction in good yields. Photophysical properties, including fluorosolvatochromism, were studied for 3ae'-3ce' and were compared with α-unsubstituted 2,2'-bipyridines. In addition, dipole moments differences in ground and excited states were calculated by both Lippert-Mataga equation and DFT studies and were compared to each other.

TM-Free and TM-Catalyzed Mechanosynthesis of Functional Polymers.

Mechanochemically induced methods are commonly used for the depolymerization of polymers, including plastic and agricultural wastes. So far, these methods have rarely been used for polymer synthesis. Compared to conventional polymerization in solutions, mechanochemical polymerization offers numerous advantages such as less or no solvent consumption, the accessibility of novel structures, the inclusion of co-polymers and post-modified polymers, and, most importantly, the avoidance of problems posed by low monomer/oligomer solubility and fast precipitation during polymerization.

Xanthone-1,2,4-triazine and Acridone-1,2,4-triazine Conjugates: Synthesis and Anticancer Activity.

A total of 21 novel xanthone and acridone derivatives were synthesized using the reactions of 1,2,4-triazine derivatives with 1-hydroxy-3-methoxy-10-methylacridone, 1,3-dimethoxy-, and 1,3-dihydroxanthone, followed by optional dihydrotiazine ring aromatization. The synthesized compounds were evaluated for their anticancer activity against colorectal cancer HCT116, glioblastoma A-172, breast cancer Hs578T, and human embryonic kidney HEK-293 tumor cell lines. Five compounds (, , , , and ) displayed good in vitro antiproliferative activities against these cancer cell lines.

Pillararenes as Promising Carriers for Drug Delivery.

Since their discovery in 2008 by N. Ogoshi and co-authors, pillararenes (PAs) have become popular hosts for molecular recognition and supramolecular chemistry, as well as other practical applications. The most useful property of these fascinating macrocycles is their ability to accommodate reversibly guest molecules of various kinds, including drugs or drug-like molecules, in their highly ordered rigid cavity.

Plant Coumarins with Anti-HIV Activity: Isolation and Mechanisms of Action.

This review summarizes and systematizes the literature on the anti-HIV activity of plant coumarins with emphasis on isolation and the mechanism of their antiviral action. This review summarizes the information on the anti-HIV properties of simple coumarins as well as annulated furano- and pyranocoumarins and shows that coumarins of plant origin can act by several mechanisms: inhibition of HIV reverse transcriptase and integrase, inhibition of cellular factors that regulate HIV-1 replication, and transmission of viral particles from infected macrophages to healthy ones. It is important to note that some pyranocoumarins are able to act through several mechanisms or bind to several sites, which ensures the resistance of these compounds to HIV mutations.

Antioxidants: Structure-activity of plant polyphenolics.

The excessive accumulation of reactive oxygen species (ROS)/free radicals can lead to abnormal oxidation of biomolecules such as proteins, lipids, fats, carbohydrates and nucleic acids in human organisms. Accordingly, endogenous oxidative stress induces the progressive development of various chronic diseases like rheumatoid arthritis, cancers, cardiovascular risks, diabetes, digestive ulcers, hypertension, obesity, neurological disorders, and age-related complications. Therefore, anti-oxidant defense mechanisms are needed to control/prevent the unbalanced molecular oxidative damage.

Comparison of Photophysical Properties of Lanthanide(III) Complexes of DTTA- or DO3A-Appended Aryl-2,2'-Bipyridines.

New Tb(III) and Eu(III) complexes based on aryl-2,2'-bipyridine ligands with a cyclic DO3A chelating unit appended in the alpha position of the bipyridine core were synthesized. The photophysical properties of these complexes were compared with those of complexes of ligands with identical aryl-2,2'-bipyridine chromophores, but with an acyclic DTTA residue as an additional chelating site in the alpha position of the bipyridine core. The nature of the polyaminocarboxylic acid fragments was found to have a significant influence on the luminescence.

Fluorescent Pyranoindole Congeners: Synthesis and Photophysical Properties of Pyrano[3,2-], [2,3-], [2,3-], and [2,3-]Indoles.

This paper reports the synthesis of four types of annulated pyranoindole congeners: pyrano[3,2-]indole, pyrano[2,3-]indole, pyrano[2,3-]indole, and pyrano[2,3-]indole and photophysical studies in this series. The synthesis of pyrano[3,2-], [2,3-], and [2,3-]indoles involve a tandem of Bischler-Möhlau reaction of 3-aminophenol with benzoin to form 6-hydroxy- or 4-hydroxyindole followed by Pechmann condensation of these hydroxyindoles with β-ketoesters. Pyrano[2,3-]indoles were synthesized through the Nenitzescu reaction of -benzoquinone and ethyl aminocrotonates and subsequent Pechmann condensation of the obtained 5-hydroxyindole derivatives.

New TEMPO-Appended 2,2'-Bipyridine-Based Eu(III), Tb(III), Gd(III) and Sm(III) Complexes: Synthesis, Photophysical Studies and Testing Photoluminescence-Based Bioimaging Abilities.

Linked to Alzheimer's disease (AD), amyloids and -protein are known to contain a large number of cysteine (Cys) residues. In addition, certain levels of some common biogenic thiols (cysteine (Cys), homocysteine (Hcy), glutathione (GSH), etc.) in biological fluids are closely related to AD as well as other diseases.

4-(Aryl)-Benzo[4,5]imidazo[1,2-]pyrimidine-3-Carbonitrile-Based Fluorophores: Povarov Reaction-Based Synthesis, Photophysical Studies, and DFT Calculations.

A series of novel 4-(aryl)-benzo[4,5]imidazo[1,2-]pyrimidine-3-carbonitriles were obtained through the Povarov (aza-Diels-Alder) and oxidation reactions, starting from benzimidazole-2-arylimines. Based on the literature data and X-ray diffraction analysis, it was discovered that during the Povarov reaction, [1,3] sigmatropic rearrangement leading to dihydrobenzimidazo[1,2-]pyrimidines took place. The structures of all the obtained compounds were confirmed based on the data from H- and C-NMR spectroscopy, IR spectroscopy, and elemental analysis.