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First examples of sterically crowded β‐ and meso‐arylated decaaryl triphyrin(2.1.1)s were synthesized by reacting β‐hexabromo meso‐tetraaryl triphyrin(2.1.1) with five different aryl boronic acids in THF/toluene/H2O (1 : 1 : 1) in the presence of catalytic amount of Pd(PPh3)4/Na2CO3 at 80 °C for 12–24 h. The X‐ray structure obtained for one of the decaaryl triphyrin(2.1.1)s revealed that the macrocycle exhibited saddle type of distortion due to steric crowding by bulky aryl substituents introduced at the six β‐carbons of meso‐tetraaryl triphyrin(2.1.1) unlike almost planar structure observed for β‐unsubstituted meso‐tetraaryl triphyrin(2.1.1). The absorption bands of decaaryl triphyrin(2.1.1)s were broadened and bathochromically shifted compared to meso‐tetraaryl triphyrin(2.1.1) and the redox potentials were dependent on the kind of aryl substituents present at the β‐pyrrole carbons in decaaryl triphyrin(2.1.1)s. DFT and TD‐DFT studies helped in understanding the alteration in the structure, spectral, and redox properties in decaaryl triphyrin(2.1.1)s compared to meso‐tetraaryl triphyrin(2.1.1). [ABSTRACT FROM AUTHOR]

Lamellarin D, a naturally occurring molecule, isolated from marine molluscs, it exhibits potent pharmacological activities, such as topoisomerase I inhibition, antiproliferation, antiviral, insecticidal, antimetastatic and anticancer effects, making it a promising candidate for drug development. This review explores the synthesis of Lamellarin D employing various methodologies. These synthetic approaches have enabled researchers to access Lamellarin D and its analogous efficiently, facilitating further investigation into their biological properties. Our study summarizes the major contributions of these efforts to the larger synthetic community, primarily focusing on general synthetic techniques toward the Lamellarin D and its counterpart since its isolation in 1997 to the present. [ABSTRACT FROM AUTHOR]

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. Moreover, an array of (poly)phenols based on coumarin and equol were later converted to diverse (hetero)aryl compounds by this optimized step-economic protocol. The synthesized compounds were then subjected to the screening of their potential antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. In our investigation, the compounds 4ah, 4eh, 4gh and 4hh exhibited promising antioxidant potential when compared to the reference standard, butylated hydroxytoluene (BHT). Structure activity relationship (SAR) studies revealed the importance of the presence of electron-donating substituents in enhancing the antioxidant activity of the synthesized compounds. [ABSTRACT FROM AUTHOR]

Developing environmentally benevolent and sustainable approaches is a vital objective of research in any field. By upholding these parameters and strategizing the methodology, herein we report the development of a new heterogeneous nanocatalyst based on Schiff base functionalized Pd(II) complex onto titania-coated magnetic nanoparticles [Pd@SB/Fe3O4–TiO2]. The developed catalytic system is well characterized with various techniques such as FE-SEM, TEM, XPS, XRD, TGA, BET, FTIR, VSM, CHN, EDX, and ICP-AES analysis. The catalytic activity of [Pd@SB/Fe3O4–TiO2] for the Suzuki coupling reaction to synthesize biaryls and for the hydrogenation reaction of aromatic nitro compounds to synthesize aromatic amines under sustainable reaction conditions was tested which revealed excellent results. Pd@SB/Fe3O4–TiO2 showed remarkably higher activity than the homogeneous PdCl2 and Pd(OAc)2, which might be due to the presence of electronic synergism between support and Pd. Schiff base functionalization provides excellent support to the palladium as leaching of the metal was not observed. The magnetic core of the catalyst ascertains its easy recoverability, thereby maintaining the sustainability of the reaction. The magnetic catalyst was easily separable with the help of an external magnet and showed very good recyclability for up to six cycles with no appreciable loss in catalytic efficiency. Furthermore, the reported catalyst remains unchanged even after six consecutive runs as established by the FTIR, XPS, and XRD analysis of the recovered catalyst. [ABSTRACT FROM AUTHOR]

In order to improve the drug-likeness qualities, the antimalarial endochin-like quinolone (ELQ) scaffold has been modified by replacing the 4-(trifluoromethoxy)phenyl portion with an isoidide unit that is further adjustable by varying the distal O-substituents. As expected, the water solubilities of the new analogs are greatly improved, and the melting points are lower. However, the antimalarial potency of the new analogs is reduced to EC50 > 1 millimolar, a result ascribable to the hydrophilic nature of the new substitution. [ABSTRACT FROM AUTHOR]

The biosynthesis of fatty acids is an important metabolic pathway in bacterial organisms. Previous studies have highlighted the synthesis of antimicrobial compounds anchored in the benzodioxepin scaffold and known for their pronounced antibacterial properties. Based on this fundamental knowledge, a series of eight innovative benzodioxepin-biphenyl amide derivatives were carefully designed and synthesized in the current research work. This was achieved through a sophisticated optimization of the synthetic methods. The scope of this study extends to a rigorous evaluation of the antibacterial properties and biocompatibility of the above-mentioned new derivatives. In particular, compound E4 proved to be an extremely effective antimicrobial agent. In addition to a detailed elucidation of the crystalline architecture of compound E4, a thorough docking study was also carried out to investigate the interactions with the enzyme FabH. [ABSTRACT FROM AUTHOR]

We have achieved an efficient synthesis of C(3)-arylphthalides by coupling C(3)-bromophthalides and arylboronic acids under palladium catalysis. The C(sp3)-C(sp2) coupling worked well in the presence of water to provide products in a high yield. [ABSTRACT FROM AUTHOR]

A palladium catalyst system based on PdCl2(PPh3)2 or PdCl2(dppf) is reported for Suzuki‐type coupling of both N‐aryl and alkyl benzotriazinones with aryl/alkenyl boronic acids to afford a series of ortho‐aryl/alkenyl benzamides in yields up to 99%, showing improvements on catalytic efficiency, substrate scope and practicality. Scope and limitations of the improved protocol have been demonstrated with more than 40 examples, including a multigram‐scale synthesis of activated o‐biphenyl amide. Large electronic and steric effects from the boronic acid counterpart have been observed, implying the transmetallation from boron to palladium should be involved in the rate‐determining step in catalytic cycle. [ABSTRACT FROM AUTHOR]

This article explores the potential of imidazo[1,2-a]pyridine-based donor-acceptor chromophores for the development of novel fluorophores and donor-acceptor chromophores. The authors conducted density functional theory calculations and proposed a modular synthesis approach to access the desired structures. The results show promising potential for the development of thermally activated delayed fluorescence emitters. The article also discusses the synthesis and characterization of a series of donor-acceptor chromophores with a 3-aminoimidazo[1,2-a]pyridine donor motif, highlighting the need for further adjustments and optimizations to improve their optoelectronic properties. The modular synthesis approach used in this study provides a versatile platform for the development of new fluorescent emitters. [Extracted from the article]

β‐Cyclodextrin has drawn significant attention as a special class of cyclic oligomers over the past few decades. They have been employed in many organic conversions as green alternative catalysts to perform satisfactorily in catalytic activity and modify the efficiency of organic reactions. Its availability, nontoxicity, low cost, renewability, and high performance in organic transformations are several benefits of cyclodextrins that have captured the interest of many research groups worldwide. In recent decades, great progress has been made in developing metal‐catalyzed coupling reactions to create carbon–carbon bonds. For the transition‐metal‐catalyzed cross‐coupling, using modified β‐cyclodextrin derivatives as catalysts is much more pleasant due to the obvious advantages such as valuable catalytic properties and the capability to create an inclusion complex with different metals. The particular purpose of this review is to summarize the application of β‐cyclodextrin‐based catalyst systems in Suzuki coupling reaction for the synthesis of biaryl compounds covering the years 2019–2023. [ABSTRACT FROM AUTHOR]

Synthetic heat transfer fluids are of immense importance for solar thermal application due to its low vapour pressure, low melting point and high heat capacity. Commonly used synthetic heat transfer fluids are biphenyl and diphenyloxide mixture, imidazolium ionic liquid and terphenyl based chemistry. However these fluids are not found effective above 400 °C operating temperatures as they tend to degrade. As per literature inputs polyaromatic based molecules like 1-phenylnaphthalene (1-PNP) and 2-methy-l-phenylnaphthalene have thermal stability above 400 °C. In the present research work a simple, efficient and environmentally benign procedure of Suzuki coupling is employed for the synthesis of these molecules in the presence of ligand free refinery Pd-spent catalyst in water. The catalyst was found to be recyclable up to 3 times without any loss of efficiency. The synthesized polyaromatic based heat transfer fluid molecules in the presence of radical quencher which indicates their potential for high temperature application. Thermal stability of synthesized polyaromatic based heat transferred fluid was enhanced by free radical quencher. So as to apply the fluid for high temperature usage. [ABSTRACT FROM AUTHOR]

Methyl 4-(1,3a,6a-triazapentalen-3-yl)benzoate (TAP1) shows interesting properties as a small molecule fluorophore. In the search for post-functionalization methods, palladium-catalyzed arylation reactions were demonstrated. Direct CH arylation reactions of TAP1 with various aryl halides resulted in 3,6-diaryltriazapentalenes TAP4, although mostly in poor yields. Bromination of TAP1 followed by Suzuki coupling, on the other hand, requires a more delicate procedure, but gave arylated products with the same regiochemistry (TAP4) in moderate to good yields. The structure of 6-phenyltriazapentalene TAP4a was confirmed by crystallographic analysis. In addition, the effect of the C6 arylation on the fluorescent properties of 3-aryl-1,3a,6a-triazapentalenes was studied in dichloromethane at room temperature and in 2-methyltetrahydrofuran at 77 K, while the photophysical properties of two saponified derivatives were measured in acetonitrile. [ABSTRACT FROM AUTHOR]

In this study, a library of 3,7-di(hetero)aryl-substituted 10-(3-trimethylammoniumpropyl)10H-phenothiazine salts is prepared. These title compounds and their precursors are reversible redox systems with tunable potentials. The Hammett correlation gives a very good correlation of the first oxidation potentials with σp parameters. Furthermore, the title compounds and their precursors are blue to green-blue emissive. Screening of the salts reveals for some derivatives a distinct inhibition of several pathogenic bacterial strains (Mycobacterium tuberculosis, Staphylococcus aureus, Escherichia coli, Aconetobacter baumannii, and Klebsiella pneumoniae) in the lower micromolar range. [ABSTRACT FROM AUTHOR]

This article reports the preparation of new mesoporous triazine‐based organic polymers and their characterization. The polymers were synthesized via a nucleophilic condensation reaction between cyanuric chloride and bisphenols or aromatic diamine linkers. As a result, two types of triazine‐based polymers were prepared: triazine‐ether and triazine‐amine polymers. The polymers reveal a mesoporous nature with surface area values ranging between 345 and 1275 m2 g−1 and mesopore volume between 0.273 and 1.03 cm3 g−1. These values were determined from argon gas isotherms at 87 K. The pore size distribution also confirmed the micro–mesoporosity, which reached up to 3.0 nm for all polymers. The triazine‐amine polymer shows good thermal oxidative stability up to 450 °C. Motivated by the mesopore size, the new polymers were also employed as palladium nanoparticle supports. The X‐ray diffraction technique indicated the successful incorporation of palladium nanoparticles, and Fourier transform infrared measurements proved that the framework of the polymers was retained after forming palladium supports. To ensure the catalytic reactivity of palladium nanoparticles, we employed one example as a catalyst in a Suzuki coupling reaction. The catalyst exhibited remarkable recyclability, maintaining catalytic efficiency through seven cycles, thereby enabling the use of palladium‐loaded triazine‐based polymeric catalysts in a variety of organic reactions in future. © 2023 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

In this current research framework, we detailed the synthesis of ten novel 2‐(1‐methyl‐1H‐indazol‐5‐yl)‐N‐arylisonicotinamide analogs (3a–j). The synthesis of these compounds (3a–j) involved a three‐step process, employing the Suzuki‐Miyaura coupling reaction, which successfully linked 1‐methyl‐1H‐indazole with isonicotinamide to satisfactory yields. The synthesized compounds were characterized using various spectroscopic techniques. To assess their potential, the anticancer activity of compounds (3a–j) was evaluated following the National Cancer Institute (NCI US) protocol against nine panels comprising different cancer cell lines, at a concentration of 10−5 M. Growth percentage (GP) and percentage growth inhibition (PGI) were calculated for each compound. Notably, the CNS cancer cell line SNB‐75 exhibited a remarkable PGI of 99.16 percent, indicating high sensitivity to the tested compound 3e. Additionally, ADMET prediction suggested that most of the synthesized compounds possess drug‐like properties, with low adverse effects and toxicity. These findings represent a significant advancement, offering potential avenues for further developments in the field of cancer research. [ABSTRACT FROM AUTHOR]

In this study, our goal was to synthesize novel aryl tacrine derivatives and assess their potential as anticancer, antibacterial agents, and enzyme inhibitors. We adopted a two-step approach, initiating with the synthesis of dibromotacrine derivatives 3 and 4 through the Friedlander reaction. These intermediates underwent further transformation into diarylated tacrine derivatives 3a-e and 4a-e using a Suzuki-Miyaura cross-coupling reaction. Thorough characterization of these novel diarylated tacrines was achieved using various spectroscopic techniques. Our findings highlighted the potent anticancer effects of these innovative compounds across a range of cancer cell lines, including lung, gynecologic, bone, colon, and breast cancers, while demonstrating low cytotoxicity against normal cells. Notably, these compounds surpassed the control drug, 5-Fluorouracil, in terms of antiproliferative activity in numerous cancer cell lines. Moreover, our investigation included an analysis of the inhibitory properties of these novel compounds against various microorganisms and cytosolic carbonic anhydrase enzymes. The results suggest their potential for further exploration as cancer-specific, enzyme inhibitory, and antibacterial therapeutic agents. Notably, four compounds, namely, 5,7-bis(4-(methylthio)phenyl)tacrine (3d), 5,7-bis(4-(trifluoromethoxy)phenyl)tacrine (3e), 2,4-bis(4-(trifluoromethoxy)phenyl)-7,8,9,10-tetrahydro-6H-cyclohepta[b]quinolin-11-amine (4e), and 6,8-dibromotacrine (3), emerged as the most promising candidates for preclinical studies. [ABSTRACT FROM AUTHOR]

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. Moreover, an array of (poly)phenols based on coumarin and equol were later converted to diverse (hetero)aryl compounds by this optimized step-economic protocol. The synthesized compounds were then subjected to the screening of their potential antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. In our investigation, the compounds 4ah, 4eh, 4gh and 4hh exhibited promising antioxidant potential when compared to the reference standard, butylated hydroxytoluene (BHT). Structure activity relationship (SAR) studies revealed the importance of the presence of electron-donating substituents in enhancing the antioxidant activity of the synthesized compounds.

The present study describes facile and uncomplicated biosynthesis of ZnO nanoparticles (NPs) using leaf extract of C. oxyacantha. The biomolecules present in the leaf extract act as capping agents. Thus, hazardous chemical agents are eliminated in this green synthesis. The exclusivity of biosynthesized ZnO NPs was investigated through UV–VIS spectrum, FT-IR, XRD, FE-SEM, and BET. In addition, the catalytic and biomedical applications of ZnO NPs were estimated thorough several studies including organic dye degradation by ZnO nanocatalyst and photo-nanocatalyst, Suzuki cross-coupling reaction photocatalysis in producing biphenyl, antioxidant, and antifungal activity. The biosynthesized ZnO NPs have a hexagonal wurtzite structure with an average grain size of 28.68 nm, and particles in range of 20 to 70 nm and spherical structure according to XRD and FE-SEM analyses. The ZnO photo-nanocatalyst with specific band gap of 2.63 eV could degrade methylene blue under UV light and sunlight in 20 and 50 min, respectively, and successfully photocatalysis the Suzuki cross-coupling reaction in production of biphenyl under LED light. Also, ZnO NPs decolorized the organic dye in 5 min after reducing methylene blue with NaBH4. By comparison to ascorbic acid, ZnO NPs were more effective at scavenging unstable DPPH at 200 μg mL−1, and analyzing the MIC and the inhibition zone against Aspergillus niger and Aspergillus brasiliensis, ZnO NPs were shown to be effective in inhibition of these microbes while the C. oxyacantha leaf extract did not inhibit any microbial growth. [ABSTRACT FROM AUTHOR]

A new polyindolocarbazole based polymer viz; ICZP4 has been synthesized via Suzuki cross coupling reaction. Subsequently, it has been modified as a semiconducting magnetic polymer hybrid (ICZP4F) with the assistance of a magnetic ferrofluid for the removal of Cr (VI) ions from waste streams. The characterization of ICZP4 has been done through FTIR, 1H NMR,13C NMR, GPC examinations. The hybrid material's (ICZP4F) physical characteristics were evaluated by XRD, FTIR, SEM, and magnetic susceptibility measurements. The ICZP4F has been identified as a powerful adsorbent for toxic Cr(VI) ions with 91% separation efficiency; achieved at a rate of 122 mg/g at a pH of 2. The isotherm analysis indicates that the adsorption process follows the Freundlich model with a regression coefficient R2 = 0.999. The adsorptive removal efficiency of the hybrid has been explained based on the synergistic effect between ICZP4 and the magnetite present in the ferrofliud. [ABSTRACT FROM AUTHOR]

Bipyridine and related compounds are starting materials or precursors for a variety of valuable substances such as biologically active molecules, ligands for catalysts, photosensitizers, viologens, and supramolecular architectures. Thus, it is important to classify their synthesis methods and understand their characteristics. Representative examples include methods using homo and heterocoupling of pyridine derivatives in the presence of a catalyst. Because bipyridine compounds strongly coordinate with metal centers, a decrease in catalytic activity and yield is often observed in the reaction system. To address this issue, this review provides insights into advances over the last ~30 years in bipyridine synthesis using metal complexes under both homogeneous and heterogeneous conditions. Moreover, strategies for bipyridine synthesis involving sulfur and phosphorous compounds are examined. These alternative pathways offer promising avenues for overcoming the challenges associated with traditional catalysis methods, providing a more comprehensive understanding of the synthesis landscape. [ABSTRACT FROM AUTHOR]

Substituted tetrahydropyrido[3,4-d]pyrimidine derivatives (2a-l) have been synthesized through a series of N-substitution, Suzuki coupling, deprotection and condensation reactions. The structure of new compounds was analysed by interpretations of FTIR,1H NMR, 13C NMR, and mass spectral data. The synthesised compounds were tested for their anti-leukaemic activity on wild type K562 (K562-WT) and IR1 and IR2 cell lines that are imatinib resistant due to clonal evolution. The compounds 2b, 2c, 2i, 2k and 8 showed were high HEK293 cells. Molecular docking studies using crystal structure of drug-resistant ABL-T315I mutant revealed the ability of these molecules to overcome resistance due to mutations in the ABL kinase. Notably, experimental and computational analyses identified that compound 8 exhibited highest anti-leukemic activity and potential to overcome drug resistance arising due to multiple molecular mechanisms.

Heterocyclic compounds can specifically regulate bacterial development by targeting specific bacterial enzymes and metabolic pathways. The ESKAPE pathogens are multidrug-resistant and cause nosocomial infections, which is one of the greatest challenges in clinical practice. The search for novel agents to combat resistant bacteria has become one of the most important areas of antibacterial research today. Heterocyclic compounds offer a valuable strategy in the fight against resistance as they can be designed to interact with bacterial targets that are less prone to developing resistance mechanisms. Bacterial histidine kinases (HKs), which are a component of two-component bacterial systems, are a promising target for new antibacterial compounds. We have designed and synthesized novel indole derivatives as antibacterial agents. Among the series, indole-coumarin (4b) and bisindole (4e) have shown the best inhibitory activity against S. aureus. Further, in silico docking studies show that compounds 4b and 4e could target histidine kinases in bacteria.

In order to improve the drug-likeness qualities, the antimalarial endochin-like quinolone (ELQ) scaffold has been modified by replacing the 4-(trifluoromethoxy)phenyl portion with an isoidide unit that is further adjustable by varying the distal O-substituents. As expected, the water solubilities of the new analogs are greatly improved, and the melting points are lower. However, the antimalarial potency of the new analogs is reduced to EC50 > 1 millimolar, a result ascribable to the hydrophilic nature of the new substitution.

A novel in-situ route was developed to load palladium nanoparticles on the graphene oxide in this paper. Palladium ions was immobilized on graphene oxide by cation exchange, then the palladium nanoparticles supported on reduced graphene oxide (Pd NPs-rGO) was prepared via the Suzuki coupling reaction to in situ formed Pd NPs without applying additional reductants, the approach is considerably more convenient and environmentally benign compared to conventional methods for the preparation of supported metal nanoparticles. To explaining the structure and morphology, the Pd NPs-rGO nanocatalyst was characterized by FT-IR, XPS, TEM, and ICP-AES measurements. The outcomes indicate that the Pd0 and Pd2+ are spread on the surface of rGO, and their ratio would affect the catalytic activity. Pd NPs-rGO has excellent catalytic performance in Suzuki coupling reaction with high yields and it could be recovered by centrifugation. Moreover, the catalyst can be recycled seven times without significant loss of activity. [ABSTRACT FROM AUTHOR]

This document provides a comprehensive overview of recent advances in Pd-catalyzed Suzuki-Miyaura cross-coupling reactions using triflates or nonaflates as alternative substrates. It explores the challenges and optimization required for successful cross-coupling reactions with triflates, highlighting the use of different triflates as electrophilic coupling partners. The document also discusses the diverse applications and methodologies of SM cross-coupling reactions using aryl triflates as substrates, including the synthesis of complex molecules, chiral compounds, and incorporation of radioactive isotopes. Additionally, it provides examples of SM cross-coupling reactions using different catalysts and reaction conditions, demonstrating the tolerance of electron-withdrawing and electron-donating groups. The document also discusses the use of nonaflates as alternatives to triflates in cross-coupling reactions and provides an overview of methods for the conversion of triflates to halides. [Extracted from the article]

Heterocyclic compounds can specifically regulate bacterial development by targeting specific bacterial enzymes and metabolic pathways. The ESKAPE pathogens are multidrug-resistant and cause nosocomial infections, which is one of the greatest challenges in clinical practice. The search for novel agents to combat resistant bacteria has become one of the most important areas of antibacterial research today. Heterocyclic compounds offer a valuable strategy in the fight against resistance as they can be designed to interact with bacterial targets that are less prone to developing resistance mechanisms. Bacterial histidine kinases (HKs), which are a component of two-component bacterial systems, are a promising target for new antibacterial compounds. We have designed and synthesized novel indole derivatives as antibacterial agents. Among the series, indole-coumarin (4b) and bisindole (4e) have shown the best inhibitory activity against S. aureus. Further, in silico docking studies show that compounds 4b and 4e could target histidine kinases in bacteria. [ABSTRACT FROM AUTHOR]

Our first total synthesis of aurantricholone established its benzotropolone core by the ring‐enlargement of a tetralone. Here we describe another total synthesis of aurantricholone. It reaches the benzotropolone core from a known olefin metathesis product via an equally known dibromide, both of which contain a ketoketal moiety. The next transformation ‐ step 9 overall ‐ engaged this motif in a β‐elimination of ROH rather than in a hydrolysis under the forcing acidic conditions indispensable in all prior benzotropolone preparations from such an intermediate. In step 10, the Csp2−Br bonds of the elimination product underwent two doubly Z‐selective Suzuki couplings with a boronylated O‐methyl 4‐methylidenetetronate. This gave penta(O‐methyl)aurantricholone. Its NMR shifts matched essentially those of a derivative of natural aurantricholone by Steglich et al. Three O−Me bonds were cleaved with BBr3/CH2Cl2 (step 11) and two O−Me bonds with LiBr/DMF (step 12). A 1 : 3 co‐crystal of aurantricholone and DMSO allowed for an X‐ray structure analysis. [ABSTRACT FROM AUTHOR]

A series of novel 2,6-diphenyl substituted imidazo[4,5-b]pyridines was designed and synthesized using optimized Suzuki cross coupling to evaluate their biological activity in vitro. The conditions of the Suzuki coupling were evaluated and optimized using a model reaction. To study the influence of the substituents on the biological activity, we prepared N-unsubstituted and N-methyl substituted imidazo[4,5-b]pyridines with different substituents at the para position on the phenyl ring placed at position 6 on the heterocyclic scaffold. Antiproliferative activity was determined on diverse human cancer cell lines, and the selectivity of compounds with promising antiproliferative activity was determined on normal peripheral blood mononuclear cells (PBMC). Pronounced antiproliferative activity was observed for p-hydroxy substituted derivatives 13 and 19, both displaying strong activity against most of the tested cell lines (IC50 1.45–4.25 μM). The unsubstituted N-methyl derivative 19 proved to be the most active derivative. There was a dose-dependent accumulation of G2/M arrested cells in several cancer cell lines after exposure to compound 19, implying a cell cycle-phase-specific mechanism of action. Additionally, the novel series of derivatives was evaluated for antiviral activity against a broad panel of viruses, yet the majority of tested compounds did not show antiviral activity. [ABSTRACT FROM AUTHOR]

Methyl 4-(1,3a,6a-triazapentalen-3-yl)benzoate (TAP1) shows interesting properties as a small molecule fluorophore. In the search for post-functionalization methods, palladium-catalyzed arylation reactions were demonstrated. Direct CH arylation reactions of TAP1 with various aryl halides resulted in 3,6-diaryltriazapentalenes TAP4, although mostly in poor yields. Bromination of TAP1 followed by Suzuki coupling, on the other hand, requires a more delicate procedure, but gave arylated products with the same regiochemistry (TAP4) in moderate to good yields. The structure of 6-phenyltriazapentalene TAP4a was confirmed by crystallographic analysis. In addition, the effect of the C6 arylation on the fluorescent properties of 3-aryl-1,3a,6a-triazapentalenes was studied in dichloromethane at room temperature and in 2-methyltetrahydrofuran at 77 K, while the photophysical properties of two saponified derivatives were measured in acetonitrile.

In this study, a library of 3,7-di(hetero)aryl-substituted 10-(3-trimethylammoniumpropyl)10H-phenothiazine salts is prepared. These title compounds and their precursors are reversible redox systems with tunable potentials. The Hammett correlation gives a very good correlation of the first oxidation potentials with σp parameters. Furthermore, the title compounds and their precursors are blue to green-blue emissive. Screening of the salts reveals for some derivatives a distinct inhibition of several pathogenic bacterial strains (Mycobacterium tuberculosis, Staphylococcus aureus, Escherichia coli, Aconetobacter baumannii, and Klebsiella pneumoniae) in the lower micromolar range.

Nanoparticles of Fe3O4 were prepared and decorated on the carbon nanotube surface, followed by palladium immobilization on the nanoparticles. The high efficiency MWCNT@Fe3O4@SiO2@CPTMO@DEA/Pd nanocatalyst was successfully obtained. Identification and determination of modified MWCNT organic functional groups were determined using infrared spectroscopy. The vibrating sample magnetometer (VSM) shows the successful arrangement of different layers on the surface of the primary magnetic nanotubes. The thermal stability of MWCNT@Fe3O4@SiO2@CPTMO@DEA/Pd was investigated by thermal gravimetric analysis (TGA). The degree of crystallization of the modified magnetic iron oxide nanocatalysts was measured by the X-ray diffraction pattern (XRD) was measured. Surface area, average pore size and total pore volume of the designed catalyst were investigated using Brimmer–Emanett–Teller (BET). Scanning electron microscopy (SEM) was applied to analyse the morphology of the catalyst structure. The designed catalyst components were analysed using the spectroscopic method of energy dispersive X-ray spectroscopy (EDS). Consequently, the catalyst was employed for the Suzuki coupling reaction in the water–ethanol mixture as a green solvent. The new catalyst benefits a simple, eco-friendly, and highly magnetic preparation method. The catalyst showed high thermal stability and good reusability. The catalyst was magnetically recovered and reused for 7 successive cycles with no significant loss of activity and selectivity. [ABSTRACT FROM AUTHOR]

Intramolecular catalyst transfer on benzoheterodiazoles was investigated in Suzuki–Miyaura coupling reactions and polymerization reactions with tBu3PPd precatalyst. In the coupling reactions of dibromobenzotriazole, dibromobenzoxazole, and dibromobenzothiadiazole with pinacol phenylboronate, the product ratios of monosubstituted product to disubstituted product were 0/100, 27/73, and 89/11, respectively, indicating that the Pd catalyst undergoes intramolecular catalyst transfer on dibromobenzotriazole, whereas intermolecular transfer occurs in part in the case of dibromobenzoxazole and is predominant for dibromobenzothiadiazole. The polycondensation of 1.3 equivalents of dibromobenzotriazole with 1.0 equivalent of para‐ and meta‐phenylenediboronates afforded high‐molecular‐weight polymer and cyclic polymer, respectively. In the case of dibromobenzoxazole, however, para‐ and meta‐phenylenediboronates afforded moderate‐molecular‐weight polymer with bromine at both ends and cyclic polymer, respectively. In the case of dibromobenzothiadiazole, they afforded low‐molecular‐weight polymers with bromine at both ends. Addition of benzothiadiazole derivatives interfered with catalyst transfer in the coupling reactions. [ABSTRACT FROM AUTHOR]

Bimetallic quantum dots (Cu-Pd and Ni-Pd) are active ligand-free catalysts for the alkenylation and arylation of aryl bromides. The catalysts are easy to synthesize by benign green protocols and characterized by various techniques. The bimetallic QD catalysts synthesized thus are superior to Pd(OAc)2 or other Pd NP catalysis of alkenylation reactions of aryl bromides with similar E-selectivity. The reaction of aryl bromide with aryl boronic acid is facile with high yields. [ABSTRACT FROM AUTHOR]

Wedelolactone, a benzofuran based natural product that can be isolated from Eclipta prostrata, exhibits a variety of biological activities. It is inefficient to obtain wedelolactone from natural sources, so it is of great significance to perform total synthesis study on this important compound. In the current study, a novel total synthesis of wedelolactone featuring palladium-catalyzed Suzuki coupling and acid-promoted intramolecular transesterification was discovered. In comparison with those reported total synthesis routes, the current strategy is more convenient and efficient, and can be used as a potential route for large scale production. [ABSTRACT FROM AUTHOR]

Herein, a sequential one‐pot process is described for accessing 9,9‐disubstituted‐9H‐fluorenes via the formation of a dual C−C bond, and this protocol is successfully extended to the total synthesis of the naturally occurring 4‐O‐demethyl‐nobilone. The overall process proceeds via Suzuki coupling between ortho‐bromobenzylic(tertiary) alcohols and arylboronic acids, followed by zinc(II) iodide‐mediated intramolecular cyclization reactions. The strategy has been applied to an inclusive range of substitutions over ortho‐bromobenzylic(tertiary) alcohols and arylboronic acids. [ABSTRACT FROM AUTHOR]

The synthesis of multiply substituted acenes is still a relevant research problem, considering their applications and future potential. Here we present an elegant synthetic protocol to afford tetra-peri-substituted naphthalene and tetracene from their tetrahalo derivatives by a Pd(0)-catalyzed C-C cross-coupling method in a single step. The newly synthesized tetracenes were characterized by NMR, HRMS, UV-vis spectrophotometry, and single-crystal X-ray diffraction (SCXRD). In addition, the first systematic computational study of the effect of chalcogenophenyl substitutions on the chiroptical properties of twistacenes was reported here. The gas phase computational studies using density functional theory (DFT) on a series of chalcogenophene-substituted tetracenes revealed that their chiroptical activity could be systematically increased via the atomistic tuning of peripheral substituents. [ABSTRACT FROM AUTHOR]

With an aim to combine the catalytic properties of Pd nanoparticles (NPs) with the excellent characteristics of porous layered double hydroxides (LDH), in the present study, four different catalysts (Pd/Fe3O4‐CoTiMgAlLDH, Pd/Fe3O4‐CoTiMgLDH, Pd/Fe3O4‐CoTiAlLDH and Pd/Fe3O4‐CoTiLDH) were synthesized by supporting Pd NPs onto four different Fe3O4‐LDH supports, which were synthesized by varying the metals in LDH. The catalytic activity of these catalysts was studied for Suzuki coupling and reductive degradation of dyes. Pd/Fe3O4‐CoTiMgLDH outperformed the other catalysts in both reactions. The synthesized catalysts were examined via different characterization techniques like X‐ray diffraction (XRD), Brunauer–Emmett–Teller analysis (BET), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), high resolution transmission electron microscopy (HR‐TEM), field emission scanning electron microscopy (FE‐SEM), energy dispersive X‐ray (EDX), energy dispersive X‐ray mapping (SEM–EDX mapping), inductively coupled plasma atomic emission spectroscopy (ICP‐AES) and vibrating sample magnetometry (VSM). On the basis of results obtained from XPS and the experimental data, Fe3O4‐CoTiMgLDH was found to be the support of choice as it not only stabilized the Pd0 NPs but also increased the electron density on the anchored Pd0 species, which enhanced the catalytic activity of Pd/Fe3O4‐CoTiMgLDH for studied organic transformations. [ABSTRACT FROM AUTHOR]

Synthesis of amino acids with isolated saturated (hetero)carbocyclic scaffold was disclosed. The method relied on Suzuki cross-coupling reaction of heteroacycloalkene triflates and N-Boc-tetrahydropyridine boron pinacolates followed by catalytic hydrogenation of the conjugated dienes thus obtained, which proceeded with good diastereoselectivity for scaffolds with two six-membered cycles and low diastereoselectivity for a five-membered analog. Several amino acid derivatives have also been obtained, i.e. amino esters, NH- and N-Boc-substituted amino acids – promising building blocks for medicinal and synthetic chemistry. [ABSTRACT FROM AUTHOR]

Human carbonic anhydrase inhibitors (hCAIs) are a key therapeutic class with a multitude of novel applications such as anticonvulsants, topically acting antiglaucoma, and anticancer drugs. Herein, a new series of 4-anilinoquinazoline-based benzenesulfonamides were designed, synthesised, and biologically assessed as potential hCAIs. The target compounds are based on the well-tolerated kinase scaffold (4-anilinoquinazoline). Compounds 3a (89.4 nM), 4e (91.2 nM), and 4f (60.9 nM) exhibited 2.8, 2.7, and 4 folds higher potency against hCA I when compared to the standard (AAZ, V), respectively. A single digit nanomolar activity was elicited by compounds 3a (8.7 nM), 4a (2.4 nM), and 4e (4.6 nM) with 1.4, 5, and 2.6 folds of potency compared to AAZ (12.1 nM) against isoform hCA II, respectively. Structure-activity relationship (SAR) and molecular docking studies validated our design approach that revealed highly potent hCAIs.

Suzuki coupling reaction is one of the useful methods for carbon‐carbon bond formation. In the present study, the aforementioned method is used to expand an aryl appendage on the indolenine nucleus of diastereomeric syn‐ and anti‐6‐bromo‐4a‐isopropyl‐2‐methyl‐2,3,4,4a‐tetrahydro‐1H‐carbazole analogs. Therefore, two sets of new diastereomeric Suzuki‐coupled products (16 compounds) were prepared. For this, diastereomeric syn‐ and anti‐6‐bromo‐4a‐isopropyl‐2‐methyl‐2,3,4,4a‐tetrahydro‐1H‐carbazole analogs were treated with arylboronic acids in the presence of palladium catalyst under thermal catalysis. Structures of synthesized compounds were inferred using spectroscopic studies. DFT‐based quantum chemical calculations were used to decipher structural attributes and stability of diastereomeric bromo‐2,3,4,4a‐tetrahydro‐1H‐carbazoles and their Suzuki‐coupled products, which revealed chair conformation for methylcyclohexane ring of syn‐compound while twist‐boat conformation for diastereomeric anti‐compound. syn‐Compound was found more stable than its anti‐isomer based on DFT‐calculations. Also, results demonstrated agreement between experimental and theoretical chemical shift values in NMR spectra with some deviations. Thus, structural elucidation based on computational advances in combination with the spectroscopic method can provide a powerful method for studying and comparing the structural attributes of diastereomeric compounds. [ABSTRACT FROM AUTHOR]

Chemical fine‐tuning of fluorophores is a pivotal step towards development of next generation fluorescent dyes for microscopy. With the advent of high‐resolution two‐photon excitation fluorescence imaging, there is a growing demand for very sensitive laser dyes that can be efficiently excited using commercial Ti:sapphire laser sources in the first near‐infrared window (NIR‐I, 780–1020 nm). Using the fluorescent dye Nile Red as the lead structure, we report a robust and concise Suzuki coupling approach for the synthesis of 14 new Nile Red analogues that feature extended π ring systems and diverse functionalities. For this set, we gauged their two‐photon excitation efficiency in NIR‐I as well as evaluated their general fluorescent properties (emission wavelength, Stokes shift, quantum yield and solvatochromism). Several of the new fluorophores were found to display very favorable characteristics. In particular, the derivative featuring a 4‐aminophenyl group in the 2‐position of Nile Red exhibited extreme solvent sensitivity, and the thien‐2‐yl substituted Nile Red derivative showed significantly redshifted emission, large Stokes shift and high two‐photon brightness. [ABSTRACT FROM AUTHOR]

Several new di- and tetracarboxylic [2.2]paracyclophane derivatives were obtained via Suzuki coupling between the appropriately brominated [2.2]paracyclophanes and 4-(methoxycarbonyl)phenylboronic acid. The reaction of one of these products, namely pp-bis(4-carboxyphenyl)[2.2]paracylophane (12), with zinc nitrate afforded a 2D coordination polymer comprising zinc-carboxylate paddlewheel clusters linked together by cyclophane cores. The zinc center is five-coordinated in a square-pyramidal geometry, with a DMF oxygen atom at the apex and four carboxylate oxygen atoms in the base. [ABSTRACT FROM AUTHOR]

Triterpenoid natural products from the Schisandraceae family have long presented a significant synthetic challenge. Lancifodilactone I, a member of the family not previously synthesized, was identified as a key natural product target, from which many other members could be synthesized. We envisaged that the core ring system of lancifodilactone I could be accessed by a strategy involving palladium-catalysed cascade cyclisation of a bromoenynamide, via carbopalladation, Suzuki coupling and 8π-electrocyclisation, to synthesize the core 7,8-fused ring system. Exploration of this strategy on model systems resulted in efficient syntheses of 5,6- and 5,8-fused systems in high yields, which represent the first such cyclisation where the ynamide nitrogen atom is 'external' to the forming ring system. The enamide functionality resident in the cascade cyclisation product was found to be less nucleophilic than the accompanying tri-/tetrasubstituted alkene(s), enabling regioselective oxidations. Application of this strategy to 7,6-, and 7,8-fused systems, and ultimately the 'real' substrate, was ultimately thwarted by the difficulty of 7-membered ring closure, leading to side product formation. Nevertheless, a tandem bromoenynamide carbopalladation, Suzuki coupling and 6/8π-electrocyclisation was shown to be a highly efficient tactic for the formation of bicyclic enamides, which may find applications in other synthetic contexts. [ABSTRACT FROM AUTHOR]

In the present study, the synthesis and characterization of magnetic nanocomposite Fe3O4@SiO2@MgAl-LDH@Au.Pd were reported and utilized in an efficient and environmentally benign protocol for the reduction of 4-nitrophenol and preparation of biphenyl derivatives. The synthesized nanocomposite was studied and identified by various analytical methods such as FT-IR, XRD, EDS, TEM, TGA, FESEM, VSM and XPS. Monitoring the progress of the reduction reaction of 4-nitrophenol to 4-aminophenol was performed by UV–Vis analysis. According to the results, 4-nitrophenol was successfully converted to the corresponding 4-aminophenol using NaBH4 in the presence of nanocomposite. Furthermore, the application of this magnetic nanocatalyst was also investigated in Suzuki coupling reaction. Consequently, the reactions of different aryl halides with phenylboronic acids led to the formation of corresponding biphenyl products in high-to-excellent yields. The recovery and reusability of Fe3O4@SiO2@MgAl-LDH@Au.Pd disclosed that it can be retrieved and reused for the next run up to 6 times with slight decline in its activity. [ABSTRACT FROM AUTHOR]

This study describes the synthesis of novel amphiphilic linear-dendritic block copolymers and their self-assembly in water to form supramolecular nanoreactors capable of catalyzing Suzuki-Miyaura coupling reactions under "green" conditions. The block copolymers were formed through copper(I)-catalyzed alkyne-azide cycloaddition between azide functionalized poly(benzyl ether) dendrons as the perfectly branched blocks, as well as bis-alkyne modified poly(ethylene glycol), PEG, as the linear block. A first-generation poly(benzyl ether) dendron (G1) was coupled to a bis-alkyne modified PEG with molecular mass of 5 kDa, forming an ABA copolymer (G1)2-PEG5k-(G1)2 (yield 62%), while a second-generation dendron (G2) was coupled to a 11 kDa bis-alkyne modified PEG to produce (G2)2-PEG11k-(G2)2 (yield 49%). The structural purity and low dispersity of the linear-dendritic copolymers were verified by size-exclusion chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Their self-assembly was studied by dynamic light scattering, showing that (G1)2-PEG5k-(G1)2 and (G2)2-PEG11k-(G2)2 formed single populations of micelles (17 nm and 37 nm in diameter, respectively). The triazole rings located at the boundaries between the core and the corona are efficient chelating groups for transition metals. The ability of the micelles to complex Pd was confirmed by 1H NMR, transmission electron microscopy, and inductively coupled plasma. The catalytic activity of the supramolecular linear-dendritic/Pd complexes was tested in water by model Suzuki-Miyaura reactions in which quantitative yields were achieved within 3 h at 40 °C, while, at 17 °C, a yield of more than 70% was attained after 17 h. [ABSTRACT FROM AUTHOR]

Bipyridine and related compounds are starting materials or precursors for a variety of valuable substances such as biologically active molecules, ligands for catalysts, photosensitizers, viologens, and supramolecular architectures. Thus, it is important to classify their synthesis methods and understand their characteristics. Representative examples include methods using homo and heterocoupling of pyridine derivatives in the presence of a catalyst. Because bipyridine compounds strongly coordinate with metal centers, a decrease in catalytic activity and yield is often observed in the reaction system. To address this issue, this review provides insights into advances over the last ~30 years in bipyridine synthesis using metal complexes under both homogeneous and heterogeneous conditions. Moreover, strategies for bipyridine synthesis involving sulfur and phosphorous compounds are examined. These alternative pathways offer promising avenues for overcoming the challenges associated with traditional catalysis methods, providing a more comprehensive understanding of the synthesis landscape.

With the advantages of good coordination and degradability, chitosan is an ideal polymeric carrier material for heterogeneous catalysts. In this paper, natural polymer chitosan was toughened and modified by blending with polyvinyl alcohol. Then, chitosan-polyvinyl alcohol thin film solid loaded palladium catalytic materials were prepared by reduction method using the excellent coordination properties of chitosan in adsorption of palladium ions. Finally, the catalytic material was applied to the Suzuki coupling reaction of halogenated benzene and phenylboronic acid. The results showed that the catalyst has good substrate tolerance, catalytic activity, and recovery performance.

This work describes the development of an efficient and reusable heterogeneous polymer supported palladium catalyst for Suzuki reaction in water. This novel catalyst system was designed through monoethanolamine (MEA) modification of nitrile group in Polyacrylonitrile (PAN) followed by metal salt (PdCl2) complexation. The resulting polymer complex (mPAN‐Pd) was then successfully optimised as an efficient heterogeneous catalyst for Suzuki reaction under ligand free conditions. The supported catalyst provided excellent reactivity in the coupling reactions of a series of aryl halides with phenyl boronic acids under mild reaction condition. The reaction proceeded in presence of 2 mol % of mPAN‐Pd catalyst at 80 °C in water and the resulting products were isolated in moderate to excellent yields upto 98 %. Furthermore, this catalyst can be conveniently recovered by simple filtration and reused at least five times without an appreciable loss in its activity or Palladium leaching. [ABSTRACT FROM AUTHOR]