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Several new derivatives of 2,2′‐bipyridines with a spacer group separated from the 2,2‐bipyridine fragment, namely, an ethynyl fragment, were obtained using the Sonagashira cross‐coupling reaction. The resulting derivatives were physically adsorbed on platinum electrode and were then used as activators of the catalytic activity of a platinum electrode in the reaction of cholesterol electrooxidation in an acetonitrile medium. Sensitivity, limit of detection and detectable concentration range were calculated, and the best results was established as 6.2±0.6 μA/mM, 0.08 mM and 0–0.3 mM, respectively. These results show that the prepared compounds adsorbed on platinum electrode are perspective systems for developing of new enzymeless cholesterol sensor based on them. [ABSTRACT FROM AUTHOR]

Composite silica materials have been developed by hydrothermal method and utilized as heterogeneous Hydrogen Bond Donor (HBD) catalysts, where the functionalized ketimine derivatives have been immobilized on the solid support. Such functional materials have been found to be efficient catalysts for the synthesis of cyclic carbonates through the installation of CO2 with epoxides. Characterization of these materials was systematically done using various spectroscopic and imaging techniques to confirm the presence of organic compounds on the silica surface. These composite materials exhibited significantly higher catalytic activity as compared to the other homogeneous methods. Additionally, this synthetic process was extremely convenient in terms of all the external parameters such as, solvent free condition at ambient reaction temperature with normal pressure of CO2, very low catalyst loading with proper regeneration and reusability of the catalyst. These facets have definitely made this technique greener and more sustainable. [ABSTRACT FROM AUTHOR]

This article presents a study on the synthesis of α-oxyalkyl ketones using visible-light photocatalysis. The researchers focused on optimizing reaction conditions and exploring the scope of the reaction. They found that various substituted α-phenyl vinyl azides reacted well with tetrahydrofuran (THF) to produce the desired products in good yields. The protocol was also successfully applied to other cyclic and chain ethers. The study provides valuable insights into the development of efficient and environmentally friendly synthetic methodologies. [Extracted from the article]

We herein report a modified, eco-friendly and atom-economical approach for the synthesis of a series of novel coumarin analogues via Suzuki–Miyaura cross-coupling methodology under mild conditions. The utilization of coumarin fluorosulfate as an atom-economical pseudohalide based electrophilic coupling partner was the key for success of our modified methodology. In addition, the use of water as a solvent, exceptionally milder reaction conditions and traditional catalytic systems further demonstrates the synthetic utility of the developed protocol. A comparative study of different pseudohalide leaving groups has been carried out in the later stage to understand the efficiency of aryl fluorosulfate. From this study, the increased hydrophilic nature of the fluorosulfate electrophilic coupling partner when compared to the other electrophiles has been realized. This allowed the increased solubility of the fluorosulfate electrophile in water under milder temperature conditions thereby furnishing the desired products in good to excellent yields. [ABSTRACT FROM AUTHOR]

Quinoxalines are an important group of N-heterocyclic compounds, which are present in a variety of natural and synthetic compounds possessing physicochemical properties and pharmacological activities. Since the earliest studies, their unique properties have led the chemical community, to embrace the challenge of synthesizing new Quinoxalines. This bioactive moiety can act as a versatile building block intermediate in synthesizing novel heterocyclic scaffolds and is considered as prime focus in medicinal chemistry research. This review aims to highlight the recent synthetic strategies and various routes employed to design and synthesize quinoxalines. Initially, we have discussed the classical methods of synthesis followed by modern methods and green methods, with an overview pertaining to their structure-activity-relationship (SAR). We entrust that, this mini review will offer a broad perspective and insights among the readers in the development of new quinoxalines scaffolds with rich bio-potent applications. [ABSTRACT FROM AUTHOR]

We have designed and synthesized a series of bioinspired pyrano[2,3-f]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-2H,8H-pyrano[2,3-f]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. Antiviral assay of the synthesized compounds showed that compound 4 has moderate activity against HIV-1 on enzymes and poor activity on the cell model. A molecular docking study demonstrates a good correlation between in silico and in vitro HIV-1 reverse transcriptase (RT) activity of the compounds when docked to the nonnucleoside RT inhibitor binding site, and alternative binding modes of the considered analogs of Calanolide A were established. [ABSTRACT FROM AUTHOR]

A series of new 2-(indol-3-yl)-6-(hetero)aryl substituted pyridines, 2-(indol-3-yl)-5-phenyl-substituted 2,2′-bipyridine and 5-aryl-6-(pyrrol-2-yl) substituted 2,2′-bipyridines were synthesized as push–pull fluorophores/probes by using a sequence of nucleophilic substitution reaction of hydrogen (SNH) and inverse-demand Diels–Alder reaction. For the obtained compounds, photophysical properties were studied. All the compounds displayed ICT-activity with a large Stokes shift (up to 197 nm) and PLQY up to 0.28. Due to dual emission in polar solvents, one specific probe was able to respond to the action of the local pH changes in the microenvironment and exhibit AIE-activity. The fluorescence titration data at different pH were analyzed to estimate a pKa value of 4.50 for that specific probe. The AIE behavior was further confirmed by means of time-resolved fluorescence lifetime measurements as well as UV-vis spectroscopic studies. The correlation of the influence of the nature of substituents on the degree of ICT state was established based on the analysis of charge transfer (CT) indices and the calculated interfragment charge transfer (IFCT) values. Finally, the fluorophores reported in this study were successfully applied for cellular imaging. [ABSTRACT FROM AUTHOR]

An environmentally friendly, metal-free, and efficient C(sp2)–S coupling reaction protocol between aniline and low-cost tetraalkylthiuram disulfides was developed to synthesize aryl dithiocarbamates. The targets for developing the method included catalyst-free, base-free, mild reaction conditions, room temperature synthesis with high yields, and broad substrate scope. Apart from this, our approach is also helpful for synthesizing potentially bioactive compounds and drug modification. An antimicrobial assay and a docking study on dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) enzymes of the three synthetic derivatives were performed to evaluate the antimicrobial potency of the new compounds and thus inhibit the enzyme's action. [ABSTRACT FROM AUTHOR]

Among the oldest marine species on the planet, the genus Salinispora is often encountered inhabiting sediments and other marine creatures in tropical and subtropical marine settings. This bacterial genus produces a plethora of natural products. The purpose of this study was to examine the potential for salinispora-based natural products (NPs) to combat the SARS-CoV-2 virus. The RCSB PDB was used to obtain the crystal structures of proteins 3CLpro and PLpro. All 125 NPs were obtained from online databases. Using Autodock Vina software v1.2.0 the molecular docking process was carried out after the proteins and ligands were prepared. Assessments of binding affinities and interacting amino acids were rigorously examined prior to MD simulations. The docking experiments revealed 35 NPs in total for both 3CLpro and PLpro, with high docking scores ranging from −8.0 kcal/mol to −9.0 kcal/mol. However, a thorough binding residue analyses of all docked complexes filtered nine NPs showing strong interactions with HIS: 41 and CYS: 145 of 3CLpro. Whereas, for PLpro, merely six NPs presented good interactions with residues CYS: 111, HIS: 272, and ASP: 286. Further research was conducted on residue–residue and ligand–residue interactions in both the filtered docked complexes and the Apo-protein structures using the Protein Contacts Atlas website. All complexes were found to be stable in CABS-flex 2.0 MD simulations conducted at various time frames (50, 125, 500, and 1000 cycles). In conclusion, salinaphthoquinone B appears to be the most promising metabolite, based on favorable amino acid interactions forming stable confirmations towards 3CLpro and PLpro enzymes, acting as a dual inhibitor. [ABSTRACT FROM AUTHOR]

Facile synthesis of amino/alkoxy/hydroxy‐carbonylated tacrine analogues by employing Pd/Co2(CO)8 mediated bimetallic catalysis is reported herein. A wide variety of amides and esters have been successfully incorporated at C‐6 of the tacrine core by employing this useful synthetic technology. The major highlight of this methodology includes the use of cobalt carbonyl in catalytic amounts to enhance the efficiency of the overall reaction. [ABSTRACT FROM AUTHOR]