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Pterins are molecules of substantial interest as they occur in nature in a number of forms with quite distinct and often indispensable roles. Chemically, the synthesis of the principle pterin scaffold is comparably simple, while the insolubility of the pterin building block renders synthetic derivatization extremely difficult. When aiming at modeling naturally occurring pterins of extended chemical structure, this is a considerable problem. A notable set of strategies was developed in the course of the present study, which are able to overcome the lack of reactivity of the pterin backbone. These include a strategic choice regarding protection groups, uncommon chemical transformation, ball milling and combinations thereof. Some novel pterins with quite distinct substitution motifs were successfully synthesized and characterized by spectroscopic and spectrometric analyses as well as single-crystal structural analyses for three of them. [ABSTRACT FROM AUTHOR]

A library of novel acid amine coupling products was synthesized and the components tested for their in vitro cytotoxicity against human breast cancer cell lines viz. MCF-7 and MDA-MB-231. One of the compounds displayed superior activity against both cell lines, with lower IC50 values compared to standard reference Doxorubicin. Two other compounds showed promising activities with encouraging IC50 values against MCF-7, and MDA-MB-231. A molecular docking study of these molecules against EGFR gave their docking scores and binding interactions, and predicted their ADME properties. [ABSTRACT FROM AUTHOR]

The non-alternant aromatic hydrocarbon azulene as a potential building block for the creation of new polymer conjugated materials is attracting more and more attention due to its unique chemical structure, optical and physico-chemical properties. The azulene conjugated polymers were synthesized by the interaction of 1,3-dibromoazulene or 2,7-bis(3-bromoazulene-1-yl)-9,9-dihexyl-9H-fluorene with 2,2'-(9,9-dihexylfluorene-2,7-diyl)bis(1,3,2-dioxaborolan) under the conditions of the Suzuki cross-coupling reaction: poly[2,7-(9,9-dihexylfluorenyl)- alt-(1',3'-azulenyl)] 3 and poly[1,3-bis(9',9'-dihexylfluorene-2'-yl)azulenyl]-alt-[1",3"-azulenyl] 5. The photophysical and thermal properties of the obtained fluorene-azulene polymers were characterized by UF-Vis and fluorescence spectroscopy, as well as methods of thermogravimetric analysis and differential scanning calorimetry. It was found that polymers 3 and 5 do not emit in a neutral state in various organic solvents. However, they become fluorescent on treatment with trifluoroacetic acid in tetrahydrofuran. The "activation" of fluorescence in protonated azulene copolymers 3-H+ and 5-H+ occurs due to the formation of the 6π-electron aromatic azulene cation, which changes the overall electronic character, in particular, the levels of the frontal molecular orbitals of the HOMO and LUMO, and then the band gap. The obtained results demonstrate that the inclusion of azulene structural units in the conjugated polymer strucrure has great potential for the development of new protonic organic functional materials. [ABSTRACT FROM AUTHOR]

Organic synthesis, both in the laboratory and in industry, usually involves the use of a variety of solvents, the choice of which is determined by the nature of the reaction and its substrates. Water rarely enters the range of solvents for organic reactions. The problem is the solubility of organic substances in water. Micellar catalysis, based on the phenomenon of solubilization and local concentrating, provides the possibility of carrying out reactions of hydrophobic substances in water. This work demonstrates the effectiveness of using polymeric surfactants for the implementation in water of Suzuki cross-coupling, which is one of the most important constructive reactions in organic chemistry. [ABSTRACT FROM AUTHOR]

Keywords: amphidinolides; polyketides; total synthesis; Suzuki cross-coupling; epoxides; protecting groups EN amphidinolides polyketides total synthesis Suzuki cross-coupling epoxides protecting groups 2017 2021 5 10/09/23 20231024 NES 231024 Graph Amphidinolide U is a moderately cytotoxic macrolide isolated from dinoflagellates of an I Amphidinium i species, with reported IC SB 50 sb values on L1210 and KB cell lines of 12 and 20 g/mL, respectively. 1994, 107 24 Ley, S V. Tackett, M N. Maddess, M L. Anderson, J C. Brennan, P E. Cappi, M W. Heer, J P. Helgen, C. Kori, M. Kouklovsky, C. Marsden, S P. Norman, J. Osborn, D P. Palomero, M. Á. Pavey, J B. J. Pinel, C. Robinson, L A. Schnaubelt, J. Scott, J S. Spilling, C D. Watanabe, H. Wesson, K E. Willis, M C. Chem. Eur. J. 2009, 15: 2874 25 Cid, M B. Pattenden, G. Synlett. Chem. 2006, 71: 5826 20 Mihelich, E D. Daniels, K. Eickhoff, D J. J. Am. Chem. Soc. 1981, 103: 7690 21 Corey, E J. Fuchs, P L. Tetrahedron Lett. Int. Ed. 2001, 40: 4544 29 Berthold, D. Breit, B. Chem. Eur. J. 2018, 24: 16770 30 Geist, E. Kirschning, A. Schmidt, T. Nat. [Extracted from the article]

In this work, for the first time, naphthalene (NA)-based polymers were synthesized by one-stage Friedel–Crafts crosslinking. The influence of NA functionalization by -OH, -SO3H, and -NO2 groups on the polymers' porosity and distribution of the catalytically active phase (Pd) was studied. Synthesized catalytic systems containing 1 wt.% of Pd either in the form of Pd(II) species or Pd(0) nanoparticles supported on NA-based polymers were tested in a model reaction of Suzuki cross-coupling between 4-bromoanisole and phenylboronic acid under mild reaction conditions (60 °C, ethanol-water mixture as a solvent). These novel catalysts demonstrated high efficiency with more than 95% of 4-bromoanisole conversion and high selectivity (>97%) for the target 4-methoxybiphenyl. [ABSTRACT FROM AUTHOR]

During the last decades, palladium nanoparticles (Pd(0) NPs) and Pd(II) compounds were shown to be attractive catalysts for fine organic synthesis. Nanostructured Pd(0) or Pd(II) catalysts have a relatively low environmental impact, but, at the same time, they are indispensable for such processes as Suzuki cross-coupling. This paper describes the preparation of Pd(0) or Pd(II) supported/embedded in hyper-cross-linked polystyrene (HPS) and compares their activity in Suzuki cross-coupling between phenylboronic acid and 4-bromoanisole. Obviously, the palladium charge (Pd(0) ↔ Pd(II)) changes continuously during the reaction catalytic cycle. It would seem that the use of the starting palladium in the form of Pd(0) or Pd(II) should not affect the reaction's kinetic laws for both catalysts, but their special individuality is manifested between them. Nanoparticulate Pd(0) catalysts are stable during the reaction. In contrast, catalysts based on Pd(II) are extremely active in the initial period of the reaction, but then the "hot form" of the catalyst is rapidly converted into the form of Pd(0), whose activity is identical to that of the preliminarily reduced catalyst. This work discusses the possible nature of this phenomenon. A mathematical model for Suzuki cross-coupling reaction was suggested that was able to adequately describe experimental data. The level of reliability (R2) of the correlation between the experimental and calculated data was R2 = 0.97–0.99. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ligand-free catalysts consisting of cheap, safe and abundant iron and copper. • The catalyst is convenient to prepare and can be easily recovered. • Broad range of adaptability of the catalyst to the substrate with yields up to 99%, TON up to 9.0 × 103. • The unique electron-donation mechanism enabled the reduction of Cu (Ⅱ) to Cu (Ⅰ) after iron doping, which greatly improved the catalytic activity. In this study, a cheap and easily recyclable "tea-bag" shaped Cu(Fe-Cl)/Al catalyst was fabricated to catalyze the Suzuki-Miyaura coupling reactions with good yields. It was found that, after being doped with iron and chlorine, catalytic activity of the materials was prominently enhanced. The unique electron-donation mechanism enabled the reduction from Cu (Ⅱ) to Cu (Ⅰ) after iron doping, which greatly improved the catalytic activity. An in-depth analysis of the reaction mechanism was then probed using characterizations such as XPS, HRTEM, and control experiments. Compared with traditional homogeneous or heterogeneous metal catalysts, this study can provide a green and economical choice to afford a free-standing recyclable catalyst with extremely high turnover numbers (TON up to 9.1 × 103) for Suzuki cross-coupling reactions. [ABSTRACT FROM AUTHOR]

Two novel series of symmetrical and unsymmetrical conjugates, in which 1,3,4-thiadiazole and 4-N,N-dimethylaminoquinazoline scaffolds were connected via 1,4-phenylene linker, were synthetized in high yields by Suzuki cross-coupling reactions. The elaborated protocol makes use of bromo-substituted quinazolines, boronic acid pinacol ester or diboronic acid bis(pinacol)ester of 2,5-diphenyl-1,3,4-thiadiazole, catalytic amounts of [1,10-bis(diphenylphosphino)ferrocene]dichloropalladium(II) Pd(dppf)Cl2, sodium carbonate, and tetrabutylammonium bromide, which plays the role of a phase-transfer catalyst. The structures of prepared compounds were confirmed by 1H NMR, 13C NMR, UV-VIS, IR and HRMS. For the target compounds, the fluorescence spectra were measured to determine their quantum yields and Stokes shifts. The study revealed that among the tested compounds, two highly-conjugated derivatives (8a, 9a), in which 1,3,4-thiadiazole core is connected to 4-(N,N-dimethylamino)quinazoline via a double 1,4-phenylene linker, exhibit high quantum yields of fluorescence and strong fluorescence emission. [ABSTRACT FROM AUTHOR]

Photocatalyzed organic transformations have spurred immense interest in synthetic chemistry for the efficient conversion of solar energy into chemical energy. However, the crucial roles of support, which fixes catalytic sites and improves the light-harvesting ability, are often ignored in photoredox transformations. Herein, we report the utilization of spherical SiO2 support to engineer AuPd alloy particles (denoted as AuPd/SiO2), conceptually different from traditional methods for tuning optical absorption of plasmonic Au or AuPd particles, to manipulate light-harvesting ability of AuPd particles for highly selective and efficient photocatalytic Suzuki cross-coupling reactions. In this deliberately designed system, typically without the size and shape alternation of AuPd particles, the supported AuPd particles recycle the scattering light from spherical SiO2 support and achieve the significant broad light-harvesting ability instead of the surface plasmon resonance peak. The engineered AuPd/SiO2 composites by the use of near-field scattering-promoted optical absorption showcase the remarkably enhanced activity for visible-light-induced photocatalytic Suzuki cross-coupling reactions in comparison with that using commercial SiO2 support, highlighting the spherical-support-effect induced efficient utilization of scattered light. This work highlights the feasibility of manipulating the light-harvesting capability of bimetallic particles by the near-field scattering-promoted optical absorption model toward efficient photo-driven Suzuki cross-coupling reaction and other C-C coupling organic synthesis to produce high value-added chemicals. [ABSTRACT FROM AUTHOR]

Palladium catalysts constitute a cornerstone of modern chemistry with upmost scientific and industrial impact. Bulk palladium metal itself is chemically inert, and a sequence of chemical transformations has to be utilized to convert the metal into a Pd precatalyst covered by ligands. However, the "cocktail" concept of catalysis discovered recently has shown that Pd systems can efficiently operate in catalysis without the need for a complicated and expensive preinstalled ligand environment. Here, we point out on a green and sustainable process for the generation of Pd active species without the need for waste-abundant precatalyst-related chemistry. In this work, an electric current was used to generate an active Pd catalyst from a bulk metal in an ionic liquid medium for the efficient cross-coupling of aryl iodides/bromides and boronic acids. A synthetically important Suzuki cross-coupling was utilized as a representative test reaction to confirm the idea. Notably, an electric current is used only at the Pd dissolution stage. Afterwards, the electrodes are removed from the reaction mixture, and a standard reaction procedure can be followed. The reported catalyst preparation process via electrochemical dissolution is potentially compatible with several already existing catalytic methods., (© 2025 Wiley-VCH GmbH.)

In this paper, the density functional theory calculations were carried out in order to find the adsorption energies of a benzene ring on small Pd0 clusters consisting of four or nine atoms. The adsorption of benzene on palladium clusters was found to result in a noticeable energy gain of the system: -146 kJ/mol in the case of Pd4, and -117 kJ/mol in the case of Pd9. The adsorption energies of chloro-, bromo- and iodoanisole on Pd4*C6H6 were also calculated. The adsorption of iodoanisole was characterized by the highest energy gain of the system (-278 kJ/mol) and occurred dissociatively without activation, that fundamentally distinguished it from chloro- and bromoanisole. The data obtained can be used to explain the differences in the behavior of catalysts based on hyper-cross-linked polystyrene in cross-coupling reactions of various aryl halides and phenylboronic acid, and also the fact that aryl iodides can favor the formation of homogeneous forms of palladium.

Lignans are widely present in traditional medicinal plants. Many natural arylnaphthalene lactone lignans (NALLs) isolated from the genera Justicia, Haplophyllum, and Phyllanthus possess interesting biological activities. Herein, we report a general strategy for the total synthesis of this kind of lignans. Features of this new approach are an aryl–alkyl Suzuki cross-coupling to introduce the dioxinone unit, a cation-induced cyclization to construct the aryl dihydronaphthalene, and base-mediated oxidative aromatization to furnish the arylnaphthalene core. By incorporating these key transformations, the total syntheses of justicidins B and E and taiwanin C covered type I and type II NALLs were accomplished.

This work describes a new route to thermally stable energetic materials by connecting different types of energetic moieties (nitropyrazole and polynitrobenzene) with C−C bonds, where the first step involves a Suzuki cross‐coupling reaction between 4‐bromo‐3,5‐dinitro‐1H‐pyrazole and 4‐chlorophenylboronic acid. Further nitration, amination, oxidation, and salt formation reactions on the resulting C−C coupled framework resulted in various thermally stable energetic materials. All the compounds were fully characterized using IR, NMR [1H, 13C{1H}], differential scanning calorimetry (DSC), elemental analysis, and HRMS studies. Compounds 7 and 9 were further characterized by 15N NMR, and compounds 3 and 6 were characterized by single‐crystal X‐ray diffraction studies. Theoretical heats of formation and energetic performance for all the energetic compounds were calculated using Gaussian 09 and EXPLO5 v6.06 programs, respectively. This research introduces a novel method for synthesizing C−C coupled energetic materials that are not accessible by any other routes. [ABSTRACT FROM AUTHOR]

We report the implementation of the ligand‐to‐metal charge transfer (LMCT) in organic semiconductors for improved full visible‐light photocatalysis and understanding of the effects of Pd−N weak coordination of a single‐atomic Pd(II) embedded 2D g‐C3N4 (Pd1/UTCN) homogeneous catalyst analogues on the formation of open metal sites and LMCT induced full‐visible‐light photocatalytic performance. LMCT between Pd(II) and g‐C3N4 allows for wide‐range visible light harvesting and promoting the transport of photogenerated charge of carbon nitride from excitation site to active site. Compared to the porphyrin palladium complex with strong Pd−N coordination, the reversible coordination dissociation of Pd−N of Pd1/UTCN allows for the formation of open active sites photocatalysis, which enables the efficient adsorption, activation, and conversion of substrates. The adsorption of the substrate can promote LMCT between Pd(II) and heptanazine ligands. As a result, Pd1/UTCN exhibited LMCT‐induced efficient full‐visible‐light photocatalytic activity of Suzuki reaction with high selectivity without additional phosphorus ligands. [ABSTRACT FROM AUTHOR]

A new mixed ligand Ni complex of phenolic Schiff base and 2,2' bipyridine was implanted on MCM-41 to prepare a simple and reusable catalyst. The designed heterogeneous catalyst has been characterized by FT-IR, PXRD analysis, N2 adsorption and desorption, SEM–EDX, TEM, ICP-OES and TGA. The synthesized Ni-MCM-41 is utilized as a potential catalyst against the Suzuki cross-coupling reaction of a wide range of aryl/alkyl/allyl halides with aryl boronic acid in DMF: water/water under microwave irradiation with the yield up to 95 / 86% of the catalytic product. Moreover, short reaction time, easy workup, eco-friendly, low cost and reusability of catalyst up to four times without a noteworthy loss of its activity are some of the merits of this method. The hot filtration test has been ratified that there was no leaching of metal during the catalytic reaction, indicating the heterogeneous manner of the catalyst. [ABSTRACT FROM AUTHOR]

Palladium-catalyzed Suzuki cross-coupling of isomeric dichloroacetophenones with phenylboronic acid in the presence of 2-dicyclohexylphosphino-2′-(dimethylamino)-biphenyl (DavePHOS, a Buchwald ligand) affords the corresponding diphenylacetophenones in high yields. The reaction of pentachloroacetophenone with phenylboronic acid (1.1–2.5 equiv.) proceeds unselectively to give isomeric mono- and disubstitution products. In the case of 3,4-dichloroanisole, 3-positioned chlorine atom is preferably replaced, however, with excess phenylboronic acid 4′;-methoxy-1,1′;:2′;,1″-terphenyl is quantitatively formed. [ABSTRACT FROM AUTHOR]

We report the synthesis of cinchonine and hydrocinchonine derived surfactants by reacting with various mono alkylating agents (hexyl, octyl, octadecyl, dodecyl bromides) and di‐alkylating agent such as α,α'‐p‐xylene‐di‐bromide. A series of chiral surfactants have been used to stabilize palladium nanoparticles (NPs) which are water soluble. These Pd NPs were utilized in asymmetric Suzuki cross coupling reaction of naphthalene boronic acids with substituted naphthalene bromides to get binaphthalenes and terephenylenes. It was observed that, the surfactant's alkyl‐chain length and the palladium source played a major role in this catalytic reaction. The high solubility and positive zeta potential of gemini‐surfactant (GS) stabilized Pd NPs make them attractive as a potential candidate for the synthesis of binaphthalenes and terephenylenes with high yields. [ABSTRACT FROM AUTHOR]

We present an environmentally benign methodology for the covalent functionalization (arylation) of reduced graphene oxide (rGO) nanosheets with arylazo sulfones. A variety of tagged aryl units were conveniently accommodated at the rGO surface via visible‐light irradiation of suspensions of carbon nanostructured materials in aqueous media. Mild reaction conditions, absence of photosensitizers, functional group tolerance and high atomic fractions (XPS analysis) represent some of the salient features characterizing the present methodology. Control experiments for the mechanistic elucidation (Raman analysis) and chemical nanomanipulation of the tagged rGO surfaces are also reported. [ABSTRACT FROM AUTHOR]

A multidimensional group testing approach was utilised for the deconvolution of reagents for a Suzuki cross-coupling reaction. This proof of concept aimed to accelerate the identification of the best reagents for such a reaction. Two deconvolution approaches showed that K2CO3, ethanol and benzyldiphenylphosphine were the optimal reagents. With this approach, the optimal reagents are identified faster, and the number of reactions is drastically reduced. [ABSTRACT FROM AUTHOR]

Donor molecules of the D-π-A-π-D type structure are often used for applications in organic photovoltaics. In this communication, bromination of 4,7-di(thiophen-2-yl)-[1,2,5]thiadiazolo[3,4-d]pyridazine followed by Suzuki cross-coupling with carbazoleboronic acid gave 4,7-bis(5-(9-hexyl-9H-carbazol-3-yl)thiophen-2-yl)-[1,2,5]thiadiazolo[3,4-d]pyridazine. The structure of the newly synthesized compounds was established by high resolution mass-spectrometry, 1H, 13C NMR, IR, and UV spectroscopy and mass-spectrometry. A study of the luminescent properties of the dye showed that it exhibits fluorescence in the near infrared region of the spectrum, which makes it a promising compound for use as an active emitting layer in NIR OLED as well as for other possible applications as an IR luminophore. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of the influence of the type of polymeric matrix of hyper-crosslinked polystyrene on activity and stability of palladium catalysts of Suzuki cross-coupling. The use of the hyper-crosslinked polystyrene functionalized with tertiary amino groups was shown to be promising in terms of ensuring of the catalyst stability during recycles, but in order to achieve 100 % conversion of aryl halide ( 4 - bromanisole) the use of strong excess of phenylboronic acid and of a base is required. The catalyst based on non-functionalized hyper-crosslinked polystyrene had higher activity and allowed achieving complete conversion of 4 - bromanisole during the reaction under mild conditions ( 70°С, ethanol and water mixture is in the ratio of 5:1 as a solvent) while using 1,5 - fold excess of phenylboronic acid. However, strong adsorption of the cross-coupling product in a hydrophobic polymeric matrix was found to be a disadvantage of such a system.

This study reports an ionic liquid (IL) promoted green method to obtain diaryl thioethers useful as key intermediates for the synthesis of matrix metalloproteinase (MMP) inhibitors. The synthetic pathway includes a sequential Ullmann reaction and Suzuki cross-coupling. The Ullmann conditions were optimized as regards the catalyst, the ionic liquid, reaction time, and temperature. Under optimal conditions (1-butyl-3-methylimidazolium bromide ([BMIM]Br) as solvent; catalyst, Cu; base, K2CO3; reaction time, 22 h; reaction temperature, 150°C) the aryl iodide conversion was 95%. The Suzuki cross-coupling was conducted in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) at 110°C, using Pd(PPh3)4 as catalyst and Na2CO3 as base. For both reactions, a combination of ILs with microwave (MW) irradiation determined a substantial improvement of reaction time and yields compared to conventional heating. This multi-step process reduces reaction times and removes organic solvents providing a more eco-friendly alternative for the synthesis of important pharmaceutical building blocks.

The synthesis of 4-phenylphenalenones, a group of phytoalexins exclusive from Musa acuminata (bananas), has been revisited to extend the scope of the derivatives that can be prepared. The discovery that 4-methoxyphenalenone participates in a selective substitution reaction allowed the preparation of 4-bromophenalenone, which proved to be an efficient substrate for Suzuki cross-couplings. The results solve the previously uncovered problem of preparing electron-rich 4-heteroarylphenalenones and provide a general synthesis of this type of phytoalexins.

An ultrasound assisted methodology has been developed for rapid synthesis of a series of biologically important 2-iminothiazolines from easily available α-bromoketones and thioureas under solvent- and catalyst-free conditions at room temperature in open air. The 2-iminothiazolines are found to exhibit moderate activity against both the representative Gram positive and Gram negative bacteria, suggesting possible scope of using them as antimicrobials. Additionally Suzuki cross-coupling of 5-bromo-2-iminothiazolines with organoboronic acids produced fully substituted 5-aryl-2-iminothiazolines in good yield.

In this study, a simple and cost‐effective approach has been reported, wherein cotton fabric containing hydroxyl groups was utilized as a support material for the immobilization of Pd(0) nanoparticles. Cotton fabric was first modified with SiO2 to enhance the thermal stability followed by functionalization with ethylene diamine to chelate Pd nanoparticles. Sodium borohydride was used for the reduction of palladium ions to nano‐sized palladium. The developed cotton fabric based catalyst was successfully applied to Suzuki cross‐coupling reaction between bromoarenes and arylboronic acids in the presence of potassium carbonate as base and selective hydrogenation of C=C double bond in α,β‐unsaturated carbonyl compounds as well as reduction of nitroarenes using molecular hydrogen as a green reductant. The structural investigation of the catalyst was done using FTIR, TGA, XRD, FEG‐SEM, ICP‐AES and XPS. The catalyst could be removed easily using lab tweezers and reused up to five reaction cycles. [ABSTRACT FROM AUTHOR]

RhCl3 was heterogenized into an iota-carrageenan polysaccharide support, and the effect of various reactor configurations on catalyst performance in a Suzuki cross-coupling reaction was studied. It was found that performing the reaction in a high-volume, well-agitated, mechanically mixed high volume reactor, or circulating the reaction mixture through the catalyst, which was placed in a tabular reactor, yielded higher product yields in comparison to magnetically stirring or shaking. In addition, the catalyst was also successfully recycled in all the systems. Moreover, the reaction solution in each reactor configuration did not contain any traces of rhodium, while elemental composition of the iota-based rhodium catalyst, i-RhCl3, following the first and the second cycle in the glass tubular reactor was similar to the fresh i-RhCl3 catalyst, demonstrating the high xerogel stability. [ABSTRACT FROM AUTHOR]

A copolymer of styrene and maleic anhydride was modified via reaction with 4-amino-5-methyl-4H-1,2,4-triazole-3-thiol, and palladium(II) chloride was then immobilized on the modified copolymer. The resulting nanocatalyst was characterized by scanning electron microscopy (SEM), energy dispersive spec-troscopy, X-ray (EDAX) and inductively coupled plasma (ICP) analyses, and FT-IR, 1H NMR, and 13C NMR spectroscopic data. The catalytic efficiency of the new palladium nanoparticles was successfully examined in the Suzuki cross-coupling reaction of various aryl halides with phenylboronic acid in water. The advantages of this strategy were easy recovery and efficient reusability of the expensive PdNPs, high yields of the cross-coupling products, short reaction times, and the use of water as a solvent for a wide range of substrates. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of influence of the type of polymeric matrix of hyper-crosslinked polystyrene on the formation of catalytically active palladium nanoparticles using palladium acetate as a precursor. It was shown that the use of nonfunctionalized hyper-crosslinked polystyrene as a support allows formation of palladium nanoparticles of larger diameter (4-10 nm) than in the case of the polymer functionalized with amino groups. However, this catalyst exhibits higher activity in the Suzuki cross-coupling reaction between 4-bromoanisole and phenylboronic acid. For the most active catalyst, the influence of the reaction temperature, solvent composition and the nature of base were studied. Moreover, the study of the influence of the aryl halide nature revealed that the use of competing substrates allows achieving 100 % conversion for 4 minutes of 4-iodoanisole in the presence of 4-bromoanisole.

There are several crucial issues that need to be addressed in the field of applied catalysis. These issues are not only related to harmful environmental impact but also include process safety concerns, mass and heat transfer limitations, selectivity, high pressure, optimizing reaction conditions, scale-up issues, reproducibility, process reliability, and catalyst deactivation and recovery. Many of these issues could be solved by adopting the concept of micro-reaction technology and flow chemistry in the applied catalysis field. A microwave assisted reduction technique has been used to prepare well dispersed, highly active Pd/Fe3O4 nanoparticles supported on reduced graphene oxide nanosheets (Pd-Fe3O4/RGO), which act as a unique catalyst for Suzuki cross coupling reactions due to the uniform dispersion of palladium nanoparticles throughout the surface of the magnetite - RGO support. The Pd-Fe3O4/RGO nanoparticles have been shown to exhibit extremely high catalytic activity for Suzuki cross coupling reactions under both batch and continuous reaction conditions. This paper reported a reliable method for Suzuki cross-coupling reaction of 4-bromobenzaldehyde using magnetically recyclable Pd/Fe3O4 nanoparticles supported on RGO nanosheets in a microfluidic-based high throughput flow reactor. Organic synthesis can be performed under high pressure and temperature by using a stainless steel micro tubular flow reactor under continuous flow reaction conditions. Optimizing the reaction conditions was performed via changing several parameters including temperature, pressure, and flow rate. Generally, a scalable flow technique by optimizing the reaction parameters under high-temperature and continuous reaction conditions could be successfully developed.

A two-step synthetic sequence was developed for the undergraduate organic chemistry laboratory using vanillin as the starting material. The multi-step synthesis was designed to replace two traditional experiments teaching electrophilic aromatic substitution and carbon–carbon bond forming chemistries with greener transformations. Vanillin is iodinated using Oxone® and potassium iodide in refluxing water, and students are tasked with determining the position of aromatic substitution using 1H NMR spectroscopy. The tan, shiny, pleasant-smelling iodovanillin is subsequently used in an aqueous Suzuki-Miyaura reaction with para-methylphenylboronic acid; strategically chosen to afford a second instructive 1H NMR spectrum. Both conventional heating and microwave conditions can be employed for the palladium-catalyzed reaction. This synthetic sequence, successfully performed over multiple semesters by hundreds of students, models green chemistry principles through the use of a potentially renewable feedstock and safer reagents, the choice of water as a safer reaction solvent, and the employment of a catalytic reaction. Additionally, the sequence minimizes waste in teaching labs through use of an intermediate product.

Overcoming the incompatibility of a pair of conflicting catalysts via a flow methodology has great significance in the practical applications for multistep organic transformations. In this study, a multiple continuous‐flow system is developed, which can boost the reactivity and selectivity in a sequential enantioselective cascade reaction. During this process, a periodic mesoporous organosilica‐supported Pd/carbene species as a Suzuki cross‐coupling catalyst is packed in the first column reactor, whereas another periodic mesoporous organosilica‐supported Ru/diamine species as an asymmetric transfer hydrogenation catalyst is packed in the second column reactor. As we envisioned, the initially Pd‐catalyzed cross‐coupling reaction of meta‐/para‐chloroacetophenones and aryl boronic acids followed by the subsequentially Ru‐catalyzed reduction provides chiral biarylols with enhanced yields and enantioselectivities. Furthermore, the advantages of the easy handling and the simple procedure make this system an attractive application in a scale‐up preparation of optically pure organic molecules under environmentally‐friendly conditions. [ABSTRACT FROM AUTHOR]

In this paper, π-conjugated copolymers, namely N -hexylphenothiazine/cyanopyridine/phenyl/benzothiadiazole, N -hexylphenothiazine/cyanopyridine/phenyl/9,9-dihexylfluorene, and N -hexylphenothiazine/cyanopyridine/phenyl/9,9-diethylhexylfluorene were readily synthesized via Pd-catalyzed Suzuki cross-coupling reaction. The polymer structures and their photophysical properties were characterized by elemental analysis, 1H NMR, GPC, TGA, XRD, UV-vis absorption and PL spectroscopy measurements. The coupling agent effect on photophysical properties of copolymers was investigated to rationally design polymers with particular physical properties to be employed in optoelectronic devices. The UV-vis absorption spectroscopy of copolymers showed λmax at a range of ∼334–474 nm and red-shifted in their films to a range of ∼342–381 nm. These copolymers displayed highly intense fluorescence in their solutions and films. The PL spectra of copolymers indicated red and near-infrared light, rendering them a prospect for being red and near-infrared light-emitting materials for PLEDs. XRD analysis demonstrated a d-spacing range of ∼3.79–4.32 Å, reflecting π-π stacking and some degree of crystallinity in some polymers, and only P1 and P2 showed peaks in the small-angle region, indicating lamellar structures. To understand the relationship between molecular structures of target materials and their photophysical and photovoltaic properties, density functional theory (DFT) and its time-dependent form (TD-DFT) were employed. [ABSTRACT FROM AUTHOR]

Imidazopyridinones and 7-azaoxindoles are two classes of heterocyclic compounds with only limited previous use in organic and medicinal chemistry. Various synthetic methods and routes have been evaluated to identify safe and robust chemistry to advanced imidazopyridinone building blocks and inhibitor structures. Preparation of the 7-azaoxindoles was challenged by instability of the core scaffold. Key to the successful isolation of the target structure was development of a mild Suzuki cross-coupling in non-aqueous media. The imidazopyridinones were potent inhibitors of the E. coli thymidylate monophosphate kinase, while the 7-azaoxindole showed low activity. The compounds were inactive in cell-based studies, indicating poor cell wall penetration. [ABSTRACT FROM AUTHOR]

The current investigation presents the synthesis, computational molecular-docking and biological activity studies of arylated thiazole coumarins. Aryl substituted thiazolyl coumarin derivatives were synthesized via Suzuki cross-coupling reaction. A detailed reaction condition optimization revealed that the Pd-PEPPSI-IPent precatalyst in only 2 mol% loading resulted in the desired product with high yield. The aim of this study was to examine the antimicrobial behavior of thiazole coumarin derivatives through in vitro and in silico studies. All the compounds showed activity against both antibacterial strains, Staphylococcus aureus and Escherichia coli, except 5d. Similarly, the compounds 5a, 5b, and 5d were found to be active against Trichoderma harzianum. The compound 5d of this series was found to have a higher activity with MIC 125 mg/ml against Trichoderma harzianum. Molecular studies showed the high activities of these compounds are due to the presence of strong H-bonding and p-p interaction with their respective targets. A good correlation was observed between computational and in vitro studies. [ABSTRACT FROM AUTHOR]

This study reports an ionic liquid (IL) promoted green method to obtain diaryl thioethers useful as key intermediates for the synthesis of matrix metalloproteinase (MMP) inhibitors. The synthetic pathway includes a sequential Ullmann reaction and Suzuki cross-coupling. The Ullmann conditions were optimized as regards the catalyst, the ionic liquid, reaction time, and temperature. Under optimal conditions (1-butyl-3-methylimidazolium bromide ([BMIM]Br) as solvent; catalyst, Cu; base, K2CO3; reaction time, 22 h; reaction temperature, 150°C) the aryl iodide conversion was 95%. The Suzuki cross-coupling was conducted in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) at 110°C, using Pd(PPh3)4 as catalyst and Na2CO3 as base. For both reactions, a combination of ILs with microwave (MW) irradiation determined a substantial improvement of reaction time and yields compared to conventional heating. This multi-step process reduces reaction times and removes organic solvents providing a more eco-friendly alternative for the synthesis of important pharmaceutical building blocks. [ABSTRACT FROM AUTHOR]

Phenyl-4,4-di(3,6-dibutoxyphthalonitrile) (3) was synthesized by the reaction of 1,4-phenylenebisboronic acid (1) and 4-bromo-3,6-dibutoxyphthalonitrile (2), using Suzuki cross-coupling reaction. The newly synthesized compound (3) was characterized by FT-IR, MALDI-MS, ESI-MS, ¹H-NMR, 13C-NMR, and 13C-DEPT-135-NMR. The fluorescence property of phenyl-4,4-di(3,6- dibutoxyphthalonitrile) (3) towards various metal ions was investigated by fluorescence spectroscopy, and it was observed thatthe compound (3) displayed a significantly 'turn-off' response to Fe3+, which was referred to 1:2 complex formation between ligand (3) and Fe3+. The compound was also studied via density functional theory calculations revealing the interaction mechanism of the molecule with Fe3+ ions. [ABSTRACT FROM AUTHOR]

An intramolecular palladium‐catalyzed trans‐carbocarbonation cascade is presented that consists of a formal anti‐carbopalladation of an internal carbon‐carbon triple bond terminated by a Suzuki cross‐coupling reaction. The key to success in obtaining the anti‐geometry of the emerging double bond is the use of alkyne units with substituents that avoid β‐hydride elimination (e. g. tert‐butyl or silyl). The products, involving tetrasubstituted double bonds embedded in a seven‐ or eight‐membered ring system, are formed in moderate to good yields. [ABSTRACT FROM AUTHOR]

An automated radiosynthesis of carbon‐11 positron emission tomography radiotracer [11C]UCB‐J for imaging the synaptic density biomarker synaptic vesicle glycoprotein SV2A was established using Synthra RNPlus synthesizer. Commercially available trifluoroborate UCB‐J analogue was used as a radiolabelling precursor, and the desired radiolabelled product was isolated in 11 ± 2% (n = 7) nondecay corrected radiochemical yield and formulated as a 10% EtOH solution in saline with molar activities of 20 to 100 GBq/μmol. The method was based upon the palladium(0)‐mediated Suzuki cross‐coupling reaction and [11C]CH3I as a radiolabelling synthon. The isolated product was cGMP compliant as demonstrated by the results of quality control analysis. [ABSTRACT FROM AUTHOR]

A simple PdCl2(TPPTS)2 complex was successfully heterogenized in polysaccharide hydrogel beads by using two different methods: (1) dropping the complex and polysaccharide solution into aqueous or ethanol solution of 0.5 M calcium chloride, and (2) dropping the complex and polysaccharide solution into an aqueous solution of chitosan (C). FTIR analyses of the different beads revealed that the complex was heterogenized via interactions between the sulfonate group on the TPPTS and the hydroxyl groups on the polysaccharides. Additionally, the effects of preparation procedure and polysaccharide type on catalytic performance of the formed heterogeneous catalysts in Suzuki cross-coupling was also tested. It was found that the palladium-based hydrogels, which were prepared by the interactions of two polysaccharides, iota carageenan (I) and C, were more active and stable than those that precipitated in the CaCl2 solution. In addition, the I-C-PdCl2(TPPTS)2 heterogeneous catalyst could be easily recycled with minor loss of activity. Moreover, the conversion rates of all heterogeneous systems employed with iodobenzene and phenylboronic acid were higher than those of their homogeneous analogues, a finding that is probably due to the presence of water, which accelerates the reaction, in the hydrogels. At last, SEM–EDS analysis of the hydrogels showed that the complex was immobilized in the hydrogels and that the I-C-PdCl2(TPPTS)2 beads were less condense than the beads that were produced with I-PdCl2(TPPTS)2 in CaCl2 solution, which can explain the higher performance of the former. [ABSTRACT FROM AUTHOR]

Chalcones are versatile molecules with potential use in various fields and technologies. The judicious choice of chalcones' building blocks allows the design of compounds with different properties and applications. In the present work, four highly conjugated carboxy-substituted chalcones with D-π-A architecture were synthesized aiming their evaluation as photosensitizers for dye-sensitized solar cells (DSSCs). In their architecture, electron-rich aldehydes were used as precursors of the donor units, and carboxylate or cyanoacrylate acceptor units were bonded to the acetophenone portion. The compounds presented intense UV–vis absorptions (ε in the order of 104 mol L−1 cm−1) centered between 322 and 429 nm, and blue to yellow fluorescence, with quantum yields ranging from less than 0.01 to 0.35. These chalcones were evaluated as photosensitizers for DSSCs, displaying short-circuit current density (I SC) ranging from 0.18 to 0.36 mA cm−2, open circuit voltage (V oc) from 0.52 to 0.56 V, fill factor (FF) between 54 and 67%, and power conversion efficiency from 0.05 to 0.13%. The two best performances were obtained with photosensitizers 6a and 7b which display the pairs dimethylaminophenyl/carboxylate and vanillin/cyanoacrylate as the donor and acceptor/anchoring units, respectively. [Display omitted] • Four novel carboxy-substituted D-π-A chalcones were synthesized. • Vanillin and other electron-rich aldehydes were used as precursors of the donor groups. • All chalcones presented intense UV–vis absorption and the ability to bind to TiO 2. • The chalcone having N(Me) 2 as donor and benzoate as acceptor/anchoring group presented the best performance in DSSCs. [ABSTRACT FROM AUTHOR]

This work addresses the Suzuki cross-coupling between 4-bromoanisole (BrAn) and phenylboronic acid (PBA) in an environmentally benign ethanol–water solvent catalysed by mono- (Pd) and bimetallic (PdAu, PdCu, PdZn) nanoparticles (NPs) stabilised within hyper-cross-linked polystyrene (HPS) bearing tertiary amino groups. Small Pd NPs of about 2 nm in diameters were formed and stabilized by HPS independently in the presence of other metals. High catalytic activity and complete conversion of BrAn was attained at low Pd loading. Introduction of Zn to the catalyst composition resulted in the formation of Pd/Zn/ZnO NPs, which demonstrated nearly double activity as compared to Pd/HPS. Bimetallic core-shell PdAu/HPS samples were 3-fold more active as compared to Pd/HPS. Both Pd/HPS and PdAu/HPS samples revealed promising stability confirmed by catalyst recycling in repeated reaction runs.

An efficient, versatile and non-destructive in situ method in reaction monitoring using vibrational spectroscopy is described. A Suzuki cross-coupling reaction was monitored in which the substrate 1-iodo-2-nitrobenzene reacted with the electrophile phenylboronic acid to form the product 2-nitrobiphenyl. To hasten the reaction, palladium(II) acetate and potassium carbonate were added to serve as a catalyst and to promote transmetalation, respectively. This reaction was monitored using near-infrared and Raman spectroscopy. The recorded data was subjected to multivariate data analysis such as principal component analysis in order to detect spectral changes signalling formation of the product. To confirm the presence of the desired product, offline analyses were performed using gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. The results demonstrate how Raman spectroscopy is able to detect the formation of the product in real time, whereas near-infrared spectroscopy fails to do so.

Oxoisoaporphine alkaloids are conveniently prepared via direct ring metalation of alkoxy-substituted isoquinolines at C-1, followed by reaction with iodine. Subsequent Suzuki cross-coupling of the resulting 1-iodoisoquinolines to methyl 2-(isoquinolin-1-yl)benzoates and intramolecular acylation of the corresponding carboxylic acids with Eaton’s reagent afforded five alkaloids of the oxoisoaporphine type. The yield of the cyclization step strongly depends on the electrophilic properties of ring B. An alternative cyclization protocol via directed remote metalation of ester and amide intermediates was investigated thoroughly, but found to be not feasible. Two of the alkaloids showed strong cytotoxicity against the HL-60 tumor cell line.

The milling ball is the catalyst. We introduce a palladium‐catalyzed reaction inside a ball mill, which makes catalyst powders, ligands, and solvents obsolete. We present a facile and highly sustainable synthesis concept for palladium‐catalyzed C−C coupling reactions, exemplarily showcased for the Suzuki polymerization of 4‐bromo or 4‐iodophenylboronic acid giving poly(para‐phenylene). Surprisingly, we observe one of the highest degrees of polymerization (199) reported so far. [ABSTRACT FROM AUTHOR]

Suzuki cross-coupling is a widely performed reaction, typically using metal catalysts under heated conditions. Acceleration of the Suzuki cross-coupling reaction has been previously explored in microdroplets using desorption electrospray ionization mass spectrometry (DESI-MS). Building upon previous work, presented here is the use of a high-throughput DESI-MS screening system to identify optimal reaction conditions. Multiple reagents, bases, and stoichiometries were screened using the automated system at rates that approach 10,000 reaction mixture systems per hour. The DESI-MS system utilizes reaction acceleration in microdroplets to allow rapid screening. The results of screening of an array of reaction mixtures using this technique are presented as product ion images via standard MS imaging software, facilitating quick readout. Instructive comparisons are provided with another method of generating droplets for reaction acceleration—the Leidenfrost technique. Acceleration factors greater than 200 were measured for brominated substrates, paralleling the DESI-MS results. Acceleration factors dropped to near unity with highly substituted pyridines, attributable to a steric effect. The reaction proceeded in the absence of a base in Leidenfrost droplets although no product formation was seen without base in the bulk or in the DESI-MS screening experiments. These differences between Leidenfrost chemistry and the bulk and in droplets formed in high-throughput DESI are tentatively attributed to extremes of pH associated with the surfaces of Leidenfrost droplets. [ABSTRACT FROM AUTHOR]

Carbon nanotubes decorated or filled with iron oxide nanoparticles were used as magnetically recoverable supports for Pd(II) Suzuki-Miyaura cross-coupling catalyst. • CNT were filled or decorated with iron oxide nanoparticles to make them magnetic. • The magnetic CNT were subsequently functionalized by xanthate radical chemistry. • Post-functionalization allowed grafting a dipyridylamine ligand on the C surface. • Palladium coordination on the ligand gave CNT-supported molecular Pd(II) catalysts. • The magnetically-recoverable catalysts were active in Suzuki-Miyaura cross-coupling. Multi-walled carbon nanotubes were filled or externally decorated with iron oxide nanoparticles to make them magnetically-recoverable. In the first case, the external surface was treated to be free of defects and oxygenated groups to favor internalization. A thermal decomposition route was followed in the second case. The formed nanoparticles were characterized and shown to consist in magnetite and/or maghemite. Moreover, when placed on the external surface of carbon nanotubes, they remained small and well-dispersed, leaving high proportion of free carbon surface for further functionalization. The intact sp2 carbon atoms were subsequently attacked by means of xanthate radical chemistry, followed by post-functionalization to graft a dipyridylamine ligand on the surface of both solids and pristine carbon nanotubes for comparison. Solids at each step of the syntheses were characterized by X-ray photoelectron spectroscopy (XPS). Palladium coordination onto the surface ligand was studied and the precursor [Pd(COD)Cl 2 ] complex gave the best results to afford CNT-supported molecular Pd(II) catalysts. XPS confirmed the +2 oxidation state of palladium on the carbon surface. The so-prepared magnetically-recoverable catalysts were successfully used in Suzuki-Miyaura cross-coupling catalytic application. [ABSTRACT FROM AUTHOR]

A two-step synthetic sequence was developed for the undergraduate organic chemistry laboratory using vanillin as the starting material. The multi-step synthesis was designed to replace two traditional experiments teaching electrophilic aromatic substitution and carbon–carbon bond forming chemistries with greener transformations. Vanillin is iodinated using Oxone® and potassium iodide in refluxing water, and students are tasked with determining the position of aromatic substitution using 1H NMR spectroscopy. The tan, shiny, pleasant-smelling iodovanillin is subsequently used in an aqueous Suzuki-Miyaura reaction with para-methylphenylboronic acid; strategically chosen to afford a second instructive 1H NMR spectrum. Both conventional heating and microwave conditions can be employed for the palladium-catalyzed reaction. This synthetic sequence, successfully performed over multiple semesters by hundreds of students, models green chemistry principles through the use of a potentially renewable feedstock and safer reagents, the choice of water as a safer reaction solvent, and the employment of a catalytic reaction. Additionally, the sequence minimizes waste in teaching labs through use of an intermediate product. [ABSTRACT FROM AUTHOR]