Synthesis and anticancer activity of bis(2-arylimidazo[1,2-a]pyridin-3-yl) selenides and diselenides: the copper-catalyzed tandem C-H selenation of 2-arylimidazo[1,2-a]pyridine with selenium

An N-linked imidazo[1,2-a]pyridine benzoheterobicyclic hybrid inhibits mitosis and cancer cell proliferation by targeting tubulin

Colchicine-site agents have strong potential to be used as tubulin-targeted anticancer agents. In this study, a series of imidazo[1,2-a]pyridine-benzoheterobicyclic hybrids linked by a nitrogen atom as N-heterocyclic imines were designed as colchicine site binding agents. Cell-based assays identified two compounds, 6b (N-(3-(4-chlorophenyl)imidazo[1,2-a](pyridin-2-yl)benzo[d]thiazol-2(3H)-imine) and 6c (N-(6-chloro-3-phenylimidazo[1,2-a]pyridin-2-yl)-1,3-dihydro-2H-benzo[d]imidazol-2-imine), as the most potent antiproliferative compounds against cervical cancer (HeLa) cells. Compound 6c inhibited purified tubulin polymerization in vitro and depolymerized microtubules in HeLa and MCF-7 cells. Additionally, 6c arrested HeLa cells in the mitotic phase, increased the production of reactive oxygen species, and induced cell death. The compound also exhibited a strong binding affinity towards the colchicine binding site on tubulin. Quantum chemical analysis and molecular docking indicated that 6c preferentially binds to tubulin in its iminic tautomeric state. The chemoinformatic analysis further revealed that 6c occupies a unique and therapeutically relevant chemical space with a favorable profile regarding physicochemical properties, ADMET, and pharmacokinetics.

Recent Insights into Bioactive Dichalcogen Derivatives: From Small Molecules to Complex Materials

Organodichalcogenides have been explored due to their therapeutic properties. They have been demonstrated to be active against several diseases such as cancer, bacteria, viruses, parasites, or neurological diseases. Among the different classes of dichalcogenides, disulfide derivatives have been widely studied, and many studies cover their therapeutical use. For this reason, this review includes the latest studies of diselenides and ditellurides derivatives with biological applications. With this aim, several bioactive small molecules containing the diselenide or ditelluride bond in their structure have been discussed. Furthermore, it should be highlighted that, in recent years, there has been an increasing interest in the development of nanomaterials for drug delivery due to their therapeutic advantages. In this context, diselenide and ditelluride-containing nanocarriers have emerged as novel approaches. The information compiled in this review includes small molecules and more complex materials containing diselenide or ditelluride bonds in their structure for different therapeutical applications, which could be helpful for the further development of novel drugs for the treatment of different diseases.

Recent Progress in Synthetic and Biological Application of Diorganyl Diselenides

Diorganyl diselenides have emerged as privileged structures because they are easy to prepare, have distinct reactivity, and have broad biological activity. They have also been used in the synthesis of natural products as an electrophile in the organoselenylation of aromatic systems and peptides, reductions of alkenes, and nucleophilic substitution. This review summarizes the advancements in methods for the transformations promoted by diorganyl diselenides in the main functions of organic chemistry. Parallel, it will also describe the main findings on pharmacology and toxicology of diorganyl diselenides, emphasizing anti-inflammatory, hypoglycemic, chemotherapeutic, and antimicrobial activities. Therefore, an examination detailing the reactivity and biological characteristics of diorganyl diselenides provides valuable insights for academic researchers and industrial professionals.

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

This article describes the detailed analysis of the reaction between arylamines, such as aniline, o-anisidine, and methyl anthranilate, with selenium dioxide in acetonitrile. A systematic analysis of the reaction products with the help of 77Se NMR and single-crystal X-ray crystallography revealed that the reaction progress follows three major reaction pathways, electrophilic selenation, oxidative polymerization, and solvent oxidation. For aniline and o-anisidine, predominant oxidative polymerization occurred, leading to the formation of the respective polyaniline polymers as major products. For methyl anthranilate, the oxidative polymerization was suppressed due to the delocalization of amine lone pair electrons over the adjacent carboxylate function, which prompted the selenation pathway, leading to the formation of two of the isomeric diorganyl selenides of methyl anthranilate. The diaryl selenides were structurally characterized using single-crystal X-ray diffraction. Density functional theory calculations suggest that the highest occupied molecular orbital of methyl anthranilate was deeply buried, which suppressed the oxidative polymerization pathway. Due to solvent oxidation, oxamide formation was also noticed to a considerable extent. This study provides that utmost care must be exercised while using SeO2 as an electrophile source in aromatic electrophilic substitution reactions.

Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

Alkynyl selenides have attracted considerable research interest recently, owing to their applications in the biological and pharmaceutical fields. The Cu-catalyzed tandem reaction for the synthesis of novel alkynyl imidazopyridinyl selenides is presented. A one-pot synthesis route afforded alkynyl imidazopyridinyl selenides in moderate to good yields. This was achieved by a two-step reaction between terminal alkynes and diimidazopyridinyl diselenides, generated from imidazo[1,2-a]pyridines and Se powder, using 10 mol % of CuI and 1,10-phenanthroline as the catalytic system under aerobic conditions. The C(sp²)–Se and C(sp)–Se bond-formation reaction can be performed in one-pot by using inexpensive and easy to handle Se powder as the Se source. The reaction proceeded with terminal alkynes having various substitutions, such as aryl, vinyl, and alkyl groups. The obtained alkynyl imidazopyridinyl selenide was found to undergo nucleophilic substitution reaction on Se atom using organolithium reagents and 1,3-dipolar azide–alkyne cycloaddition based on the alkyne moiety.

Reaction of imidazo[1,2-a]pyridines with coumarin-3-carboxylic acids: a domino Michael addition/decarboxylation/oxidation/annulation

A palladium-catalyzed decarboxylative domino reaction of imidazo[1,2-a]pyridines and coumarin-3-carboxylic acids has been developed, which provides access to dibenzoisochromenoimidazo[1,2-a]pyridin-6-ones possessing six fused rings.

Copper-catalyzed three-component reaction to synthesize polysubstituted imidazo[1,2-a]pyridines

An efficient three-component one-pot and operationally simple cascade of 2-aminopyridines with sulfonyl azides and terminal ynones is reported, providing a variety of polysubstituted imidazo[1,2-a]pyridine derivatives in moderate to excellent yields. In particular, the reaction goes a through CuAAC/ring-cleavage process and forms a highly active intermediate α-acyl-N-sulfonyl ketenimine with base free.

Three-component one-pot synthesis of polysubstituted imidazo[1,2-a]pyridine derivatives through a base free CuAAC/ring-cleavage process.

Gold-catalyzed oxidation of terminal alkynes to glyoxals and their reactions with 2-phenylimidazo[1,2-a]pyridines: one-pot synthesis of 1,2-diones

A novel one-pot protocol for the convenient and efficient synthesis of (2-phenylimidazo[1,2-a]pyridin-3-yl)alkane-1,2-diones (3) in good yields (32-88%) from 2-phenylimidazo[1,2-a]pyridines (1) and terminal alkynes (2) has been established with a wide range of substrate scope. A tandem reaction sequence containing gold-catalyzed double oxidations of terminal alkynes to generate glyoxals, nucleophilic addition of 2-phenylimidazo[1,2-a]pyridines to glyoxals to yield α-hydroxyl ketones, and oxygenation of the α-hydroxyl ketones to afford the final products 3 under air atmosphere is involved in this method. Simple operation, mild reaction conditions, and widely available substrates make this strategy more affordable.

Small molecule selenium-containing compounds: Recent development and therapeutic applications

Selenium (Se) is an essential micronutrient of organism and has important function. It participates in the functions of selenoprotein in several manners. In recent years, Se has attracted much attention because of its therapeutic potential against several diseases. Many natural and synthetic organic Se-containing compounds were studied and explored for the treatment of cancer and other diseases. Studies have showed that incorporation of Se atom into small molecules significantly enhanced their bioactivities. In this paper, according to different applications and structural characteristics, the research progress and therapeutic application of Se-containing compounds are reviewed, and more than 110 Se-containing compounds were selected as representatives which showed potent activities such as anticancer, antioxidant, antifibrolytic, antiparasitic, antibacterial, antiviral, antifungal and central nervous system related effects. This review is expected to provide a basis for further study of new promising Se-containing compounds.

Diselenides and Selenocyanates as Versatile Precursors for the Synthesis of Pharmaceutically Relevant Compounds

Organoselenium chemistry has undergone extensive development during the past decades, mostly due to the unique chemical properties of organoselenium compounds that have been widely explored in a number of synthetic transformations, as well as due to the interesting biological properties of these compounds. Diselenides and selenocyanates constitute the promising classes of organoselenium compounds that possess interesting biological effects and that can be used in the preparation of other selenium compounds. The combination of diselenide and selenocyanate moieties with other biologically relevant molecules (such as heterocycles, steroids, etc.) is a way for the development of compounds with promising pharmaceutical potential. Therefore, the aim of this review is to highlight the recent achievements in the use of diselenides or selenocyanates as precursors for the synthesis of pharmaceutically relevant compounds, preferentially compounds with antitumor and antimicrobial activities.