Suzuki-Miyaura Coupling Reaction Research Articles

Synthesis of novel 7-substituted pyrido[3,2-b]pyrazin-3(4H)-one derivatives via Suzuki-Miyaura cross-coupling reaction

In this work, 7-substituted Pyrido[3,2-b]pyrazin-3(4H)-one derivatives are reported starting from 4-methyl-3-nitropyridin-2-amine [1], which underwent further transformations followed by Suzuki–Miyaura coupling reaction under microwave conditions. Primarily, 5-bromo-4-methyl-3-nitropyridin-2-amine (Conejo-Garcia et al., 2010) [2] was prepared according to literature, was converted into many other derivative forms that involve different types of reactions like, reduction, cyclization, chlorination, N-alkylation and yielded as 7-bromo-2,8-dimethyl-4-(2-oxo-2-(pyrrolidin-1-yl)ethyl)pyrido[2,3-b]pyrazin-3(4H)-one (Kamble et al., 2016) [6] which was further subjecting with versatile boronic acids via Suzuki–Miyaura coupling to make comparable novel 7-substituted Pyrido[3,2-b]pyrazin-3(4H)-one derivatives (8a-p). The chemical constructions of all yielded compounds were well elucidated by analytical and spectral analyses (TLC, 1H NMR, 13C NMR, and HRMS).

Pd(OAc)2/P–COF: A phosphine-based COF supported palladium-salt heterogeneous catalyst for Suzuki-Miyaura coupling reactions at ambient conditions

A new type of phosphine covalent organic frameworks (P-COFs) has garnered interest because of their high specific surface area and good thermal stability. These microporous materials have potential applications in gas storage, separation, heterogeneous catalysis, and other fields. Here, we present a heterogeneous catalyst consisting of a phosphine-based COF supported by palladium salt (Pd(OAc)2/P-COF) for Suzuki-Miyaura coupling reactions. The electron-rich heteroatoms (P, N) can securely anchor the active component (Pd) within the walls of P–COF. This catalyst exhibits excellent catalytic activity and cyclic stability. The coupling yield of phenylboronic acid and chlorobenzene with low activity reaches 100 % at room temperature for 3 h. After five cycles, the coupling yield of bromobenzene and phenylboronic acid remains above 93 %.

Core-Shell Gold Nanoparticles@Pd-Loaded Covalent Organic Framework for In Situ Surface-Enhanced Raman Spectroscopy Monitoring of Catalytic Reactions.

A core-shell nanostructure of gold nanoparticles@covalent organic framework (COF) loaded with palladium nanoparticles (AuNPs@COF-PdNPs) was designed for the rapid monitoring of catalytic reactions with surface-enhanced Raman spectroscopy (SERS). The nanostructure was prepared by coating the COF layer on AuNPs and then in situ synthesizing PdNPs within the COF shell. With the respective SERS activity and catalytic performance of the AuNP core and COF-PdNPs shell, the nanostructure can be directly used in the SERS study of the catalytic reaction processes. It was shown that the confinement effect of COF resulted in the high dispersity of PdNPs and outstanding catalytic activity of AuNPs@COF-PdNPs, thus improving the reaction rate constant of the AuNPs@COF-PdNPs-catalyzed hydrogenation reduction by 10 times higher than that obtained with Au/Pd NPs. In addition, the COF layer can serve as a protective shell to make AuNPs@COF-PdNPs possess excellent reusability. Moreover, the loading of PdNPs within the COF layer was found to be in favor of avoiding intermediate products to achieve a high total conversion rate. AuNPs@COF-PdNPs also showed great catalytic activities toward the Suzuki-Miyaura coupling reaction. Taken together, the proposed core-shell nanostructure has great potential in monitoring and exploring catalytic processes and interfacial reactions.

Hydrazine electrooxidation performance of cyano-substituted indole derivatives as organic anode catalyst

Here we present the new EWG-substituted indole derivatives, namely 2-((5-(1-methyl-2-phenyl-1 H-indol-3-yl)thiophen-2-yl)methylene) malonitrile (IPTM), 2-((5-(1-methyl-2-phenyl-1 H-indol-3-yl)furan-2yl)methyl)malonitrile(IPFM) and 2-((4-(1-methyl-2-phenyl-1 H-indol-3-yl)benzylidene) malonitrile (IPPM) was synthesized by using Sonogashira coupling, electrophilic cyclization, Suzuki-Miyaura coupling and condensation reactions. The isolated yields were obtained as 86 %, 71 %, and 69 % yields, respectively. Cyclic voltammetry(CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) were used for the electrochemical measurements to observe the electrocatalytic behavior of IPTM, IPFM and IPPM. The results exhibited that the highest-performance organic-based catalyst was 2.601 mA/cm2 (0.073 mA/mg) for IPPM which could be a good candidate as a metal-free electrocatalyst for hydrazine electrooxidation.

Micropores in Hollow Organic Cage Nanocapsule as a Size Exclusion Gate: Cage Entrapped Pd(II)-Catalyst for Efficient Cross-Coupling Reaction.

Hollow porous organic capsules (HPOCs) with an entrapped active catalyst have nanosized cavities, providing the benefits of a nanoreactor, as well as separation of the catalysts from the reaction medium via pores acting as a size-exclusion gate. Such purpose-built HPOCs with desired molecular weight cutoffs offer the advantages of semipermeable membrane separation and a sustainable chemical process that excludes energy-extensive separation. Here, we report a newly synthesized HPOC with an entrapped Pd(PPh3)2Cl2 as the catalyst for demonstrating a Suzuki-Miyaura coupling reaction as a proof of concept.

Palladium catalyst immobilized on functionalized hyper–cross-linked polymers with 8-hydroxyquinoline as monomer for Suzuki–Miyaura coupling reactions

Palladium catalyst immobilized on functionalized hyper–cross-linked polymers with 8-hydroxyquinoline as monomer for Suzuki–Miyaura coupling reactions

Tweaking the Non-Volatile Write-Once-Read-Many-Times (WORM) Memory using Donor-Acceptor Architecture with Isatin as Core Acceptor.

Organic memory devices have attracted attention because they promise flexible electronics, low manufacturing costs, and compatibility with large-scale integration. A series of new D-A architectures were synthesized employing different donor groups and the isatin moiety as the acceptor through Suzuki-Miyaura coupling reactions. Strong intramolecular interactions were observed in the synthesized compounds, further corroborated by an optimal bandgap. The SEM investigation confirmed good molecular ordering and superior thin film surface coverage. All the compounds demonstrated notable binary Write-Once-Read-Many-Times (WORM) memory behaviour. The threshold switching voltage for these D-A systems ranged from -0.79 to -2.37 V, with the compound having isobutyl substituent showing the lowest threshold voltage and maximum ON/OFF ratio of 102, thus outperforming others. The combined effects of charge transfer and charge trapping are responsible for the resistive switching mechanism prevailing in these systems. The alterations in D-A molecules that affect molecular packing, thin film morphology, and, finally, the memory performance of the active layer are highlighted in this work.

Synthesis of N,N′-alkylidene bisamides and Suzuki–Miyaura coupling reaction derivatives with Pd organometallic catalyst anchored to channels of mesoporous silica MCM-41

At first, an organometallic catalyst namely, Pd-DPyE@MCM-41@MNP was prepared through magnetic (Fe3O4) nanoparticles-doped into channels of mesoporous silica MCM-41 and then, anchoring a novel complex composed of di(4-pyridyl)ethylene and palladium on the inner surface of the support. This immobilized catalyst was successfully identified via VSM, ICP-OES, TEM, FTIR, TGA, SEM, BET, XRD, EDX and elemental mapping analyses. After that, it was used as a versatile, heterogeneous, and magnetically reproducible catalyst in the generation of N,N′-alkylidene bisamides (1a-13a, 8–20 min, 90–98%, 50 °C, solvent-free) and Suzuki–Miyaura coupling (SMC) reaction derivatives (1b-26b, 10–140 min, 86–98%, 60 °C, PEG-400). The VSM plot of Pd-DPyE@MCM-41@MNP displays that this nanocatalyst can be easily recycled by applying an external magnetic field. In both synthetic paths, this nanocatalyst was reused at least seven times without palladium leaching and significantly reducing its catalytic performance. Also, stability and heterogeneous nature of catalyst were approved via ICP-OES technique and hot filtration test.

Carbonized cellulose microspheres loaded with Pd NPs as catalyst in p-nitrophenol reduction and Suzuki-Miyaura coupling reaction

Catalytic reduction of p-nitrophenol is usually carried out using transition metal nanoparticles such as gold, palladium, silver and copper, especially palladium nanoparticles, which are characterized by fast reaction rate, high turnover frequency, good selectivity and high yield. However, the aggregation and precipitation of the metals lead to the decomposition of the catalyst, which results in a significant reduction of the catalytic activity. Therefore, the preparation of homogeneous stabilized palladium nanoparticle catalysts has been widely studied. Stabilized palladium nanoparticles mainly use synthetic polymers. Cellulose microspheres, as a natural polymer material with low cost and porous fiber network structure, are excellent carriers for stabilizing metal nanoparticles. Cellulose microspheres impregnated with palladium metal nanoparticles were carbonized to have a larger specific surface area and highly dispersed palladium nanoparticles, which exhibited excellent catalytic activity in the catalytic reduction of 4-nitrophenol. In this aspect, cellulose carbon-based microspheres Pd nanoparticles (Pd@CCM) catalysts were designed and characterized by SEM, TEM, EDS, XRD, FTIR, XPS, TGA, BET and so on. Furthermore, the catalytic performance of Pd@CCM catalysts were investigated via 4-nitrophenol reduction, which showed high catalytic activity. This catalyst also exhibited excellent catalytic performance in Suzuki-Miyaura coupling reaction. Linking aromatic monomer and benzene through Suzuki-Miyaura coupling was presented as an effective route to obtain polymeric substrate with low-cost and simple synthesis method. In addition, cellulose carbon-based microspheres Pd nanoparticles catalyst showed desirable recyclability with maintaining its catalytic activity even after five recycles. This work is highly suggestive on the heterogeneous catalysts design and application.

Cross-coupling and dehalogenation reactions of novel π-conjugated polymers bearing high-soluble coumarin unit in the main chain and their acid-base responsive fluorescence

A highly soluble coumarin monomer, 3,7-dibromo-4-octyloxycoumarin, was developed as the novel building block for π −conjugated polymers. Sonogashira coupling reaction, dehalogenation reaction, and Suzuki-Miyaura coupling reaction were carried out by using this new monomer as the main chain unit of π −conjugated polymer for polymerization. Introduction of a long alkoxy chain into coumarin monomer unit significantly improved the solubility of thus obtained polymers. The absorption and emission spectra of polymers showed red-shift compared to those of monomer, indicating the expansion of the π −conjugated system in the polymer main chain. Especially the polymers synthesized via Sonogashira coupling formed excimer in film state. The polymers showed acid-base responsibility with the addition of KOHaq and HClaq.

Gold-Catalyzed C(sp3)-C(sp2) Suzuki-Miyaura Coupling Reaction.

A gold-catalyzed C(sp3)-C(sp2) Suzuki-Miyaura coupling reaction facilitated by ligand-enabled Au(I)/Au(III) redox catalysis was developed. The cross-coupling of alkyl organometallics was first realized in the redox catalytic cycle in gold chemistry, without the use of external oxidants. This gold-catalyzed C(sp3)-C(sp2) coupling reaction allows a variety of alkyl chain and useful methyl trifluoroborates to react with aryl and vinyl iodides under very mild conditions, which provides a new reactivity pattern for challenging couplings with alkyl organometallics.

Phenanthrothiophene-Triazine Star-Shaped Discotic Liquid Crystals: Synthesis, Self-Assembly, and Stimuli-Responsive Fluorescence Properties.

Lipophilic biphenylthiophene- and phenanthrothiophene-triazine compounds, BPTTn and CPTTn, respectively, were prepared by a tandem procedure involving successive Suzuki-Miyaura coupling and Scholl cyclodehydrogenation reactions. These compounds display photoluminescence in solution and in thin film state, solvatochromism with increasing solvent's polarity, as well as acidochromism and metal ion recognition stimuli-responsive fluorescence. Protonation of BPTT10 and CPTT10 by trifluoroacetic acid results in fluorescence quenching, which is reversibly restored once treated with triethylamine (ON-OFF switch). DFT computational studies show that intramolecular charge transfer (ICT) phenomena occurs for both molecules, and reveal that protonation enhances the electron-withdrawing ability of the triazine core and reduces the band gap. This acidochromic behavior was applied to a prototype fluorescent anti-counterfeiting device. They also specifically recognize Fe3+ through coordination, and the recognition mechanism is closely related to the photoinduced electron transfer between Fe3+ and BPTT10/CPTT10. CPTTn self-assemble into columnar rectangular (Colrec) mesophase, which can be modulated by oleic acid via the formation of a hydrogen-bonded supramolecular liquid crystal hexagonal Colhex mesophase. Finally, CPTTn also form organic gels in alkanes at low critical gel concentration (3.0 mg/mL). Therefore, these star-shaped triazine molecules possess many interesting features and thus hold great promises for information processing, liquid crystal semiconductors and organogelators.

Highly efficient metal free aldehyde-functionalized indoles for direct glucose fuel cell anode catalyst

In this study, alternative organic catalysts to metal-containing catalysts for glucose electrooxidation were prepared by the Suzuki Miyaura coupling reaction method and characterized by nuclear magnetic resonance (NMR), fourier transform infrared spectroscopy (FT-IR), and liquid chromatography with tandem mass spectrometry (LC-MS-MS). InTA-1, InPA-1, InFA-1, InTA-2, InPA-2, InFA-2, InTA-3, InFA-3, and InPA-3 were obtained with the yield of 74%, 82%, 72%, 70%, 75%, 68%, 60%, 71%, and 85%. Among the synthesized catalysts, the InTA-3 catalyst possesses the highest electrocatalytic activity (3.17 mA cm−2) and long-term stability compared to other organic catalysts. InTA-3 catalyst has the lowest charge transfer resistance toward glucose electrooxidation. It was concluded that as a metal-free catalyst, InTA-3 is a cheap and promising electrocatalyst for direct glucose fuel cell anode.

Unique biomedical application of fluorescence derivatization based on palladium-catalyzed coupling reactions for HPLC analysis of pharmaceuticals and biomolecules.

Palladium-catalyzed coupling reactions are versatile and powerful tools for the construction of carbon-carbon bonds in organic synthesis. Although these reactions have favorable features that proceed selectively in mild reaction conditions using aqueous organic solvents, no attention has been given to their application in the field of biomedical analysis. Therefore, we focused on these reactions and evaluated the scope and limitations of their analytical performance. In this review, we describe the pros and cons and future trends of fluorescence derivatization of pharmaceuticals and biomolecules based on palladium-catalyzed coupling reactions such as Suzuki-Miyaura coupling, Mizoroki-Heck coupling, and Sonogashira coupling reactions for HPLC analysis.

Efficient catalysis of Pd (II) supported by thiourea covalent organic framework in Suzuki coupling reaction

Covalent organic frameworks (COFs) were ideal carriers for noble metal catalysts due to their rich pore structure, pre-designable monomers, and high stability. Herein, a series of novel thiourea-based COFs (Tx-COFs) enriched with heteroatoms were constructed to provide abundant and powerful anchoring sites for metal. The successful preparation of Pd@COFs with high metal dispersion and substantial active sites was confirmed by XPS and STEM-EDX element mapping. These catalysts exhibited excellent catalytic activity and stability for the Suzuki-Miyaura coupling reaction. Especially for Pd@TU-COF, the catalyst still catalyzed the reaction at room temperature to afford the product in a yield of 99 % after 10 reuses, while the palladium load only decreased from 5.78 % to 5.66 %. The structure-activity relationships between the metal loading mode, the structure of Tx-COF, and its catalytic performance were also investigated in this study, which provided a feasible strategy for the preparation of efficient and stable heterogeneous catalysts.

Facile synthesis of Pd loaded g-C3N4/TiO2 heterojunction catalyst with enhanced photothermal catalytic performance in Suzuki coupling under moderate condition

Photothermal synergistic catalysis of Suzuki-Miyaura coupling reaction not only utilizes the solar energy efficiently, but also reduces the energy consumption. It is a green organic synthesis method for constructing C–C bonds, which has a wide application. In this work, we constructed a PdO/g-C3N4/TiO2 bilayer tubular structure material with a heterojunction structure by a simple and effective method. The catalyst exhibited efficient photothermal synergistic catalytic performance in Suzuki coupling reaction under visible light irradiation. The influence of the catalyst’s structure, morphology, composition, and photothermal response on the Suzuki coupling reaction were discussed based on a series of characterizations and activity test of the catalyst. The results showed that the PdO/g-C3N4/TiO2 catalyst contained an effective g-C3N4/TiO2 heterojunction structure. Under visible illumination, the differences in interfacial charge concentration and electron affinity between these two different types of semiconductors lead to charge rearrangement and transfer, which greatly improves the carrier separation efficiency. Meanwhile, palladium metal exhibits excellent electron deposition effects, both as an active metal center for SMC reactions and as an electron acceptor for facilitating photoelectron transfer. Electron-rich palladium atoms play an important role in C–C bond formation reactions, improving catalytic efficiency. The PdO/g-C3N4/TiO2 catalyst has excellent catalytic activity and can catalyze the SMC reaction under visible light and at 0 ℃, the yield reached 85.6%, which is comparable to the activity of thermal catalysis for 15 minutes. Furthermore, after five cycles, the PdO/g-C3N4/TiO2 catalyst still maintained an 83.1% yield, demonstrating excellent cycle stability. This article offers an effective strategy for preparing heterojunction catalyst with visible light response for photothermal reaction and presents the potential of these catalysts as a way to improve the efficiency and sustainability of Suzuki coupling reactions.

Palladium nanoparticles (Pd NPs) immobilized over polydopamine-functionalized Zn-Al mixed metal oxide as a novel nanocatalyst for synthesis of C-C bond via Suzuki-Miyaura coupling reactions

In recent times modified hydrotalcite like compounds formed with metal oxide layers has gained considerable importance as improved nanoparticle (NP) supports along with their unique electronic properties that inherently stabilizes the immobilized NPs. The present work demonstrates an adapted protocol towards the Pd NPs immobilized polydopamine modified Zn-Al mixed metal oxides (Zn-Al MMO@PDA/Pd NPs). Polydopamine was chosen as a biotemplate and a green reductant for the synthesis Pd NPs in situ without having any harsh reagent. Hitherto, this is the first design and biogenic synthesis of Pd NPs impregnated coordination on Zn-Al mixed metal oxides (Zn-Al MMO) and subsequent catalytic application towards the Suzuki-Miyaura coupling reactions. Subsequently, its physicochemical features were evaluated applying diverse methods like Field Emission Scanning Electron Microscopy (FE-SEM), X-ray elemental mapping (WDX), Energy Dispersive X-ray Spectroscopy (EDX) and X-Ray Diffraction (XRD) study. The Zn-Al MMO@PDA/Pd NPs nanocatalyst was isolated by centrifuger and stable enough to be reused for 8 consecutive times without considerable loss in activity.

Single ferroelectric liquid crystal compounds targeted for optical voltage sensing

Nine compounds containing fluorine or chlorine atoms in the lateral position in the rigid core with a chiral terminal octyloxy-chain were synthesized mainly using Suzuki-Miyaura coupling, Mitsunobu, hydrogenation, and esterification reactions. New compounds were investigated using polarized optical microscopy (POM), differential scanning calorimetry (DSC), spectrophotometry, and electro-optical methods. A computational analysis of the effect of lateral substitution by halogen atoms on the phenyl ring on the dipole moment of the compound was provided and discussed. The designed compounds exhibit a wide temperature range of the ferroelectric phase (>40.0 °C), a low melting point (in most cases below 50.0 °C), low melting enthalpy (around 10.0–20.0 kJ/mol), a short helical pitch (in most cases below 200 nm at room temperature) and high tilt angle that ensures a cone angle of up to 90°; all those properties make them of great potential for the deformed helix ferroelectric (DHF) mode. Revealed features allow synthesized compounds in fully integrated polarization-based photonic transducers to have excellent linearity and the highest sensitivity observed in ferroelectric liquid crystals for DHF mode. For the first time, the DHF effect was reached for the single molecule FLC material in a broad temperature range down to 38 °C. These findings pave the way for a new class of optical sensors for, among others, industrial monitoring networks and brain/machine interfaces with unprecedented performance.

Biosynthesis Parameters Control the Physicochemical and Catalytic Properties of Microbially Supported Pd Nanoparticles.

The biosynthesis of Pd nanoparticles supported on microorganisms (bio-Pd) is achieved via the enzymatic reduction of Pd(II) to Pd(0) under ambient conditions using inexpensive buffers and electron donors, like organic acids or hydrogen. Sustainable bio-Pd catalysts are effective for C-C coupling and hydrogenation reactions, but their industrial application is limited by challenges in controlling nanoparticle properties. Here, using the metal-reducing bacterium Geobacter sulfurreducens, it is demonstrated that synthesizing bio-Pd under different Pd loadings and utilizing different electron donors (acetate, formate, hydrogen, no e- donor) influences key properties such as nanoparticle size, Pd(II):Pd(0) ratio, and cellular location. Controlling nanoparticle size and location controls the activity of bio-Pd for the reduction of 4-nitrophenol, whereas high Pd loading on cells synthesizes bio-Pd with high activity, comparable to commercial Pd/C, for Suzuki-Miyaura coupling reactions. Additionally, the study demonstrates the novel synthesis of microbially-supported ≈2nm PdO nanoparticles due to the hydrolysis of biosorbed Pd(II) in bicarbonate buffer. Bio-PdO nanoparticles show superior activity in 4-nitrophenol reduction compared to commercial Pd/C catalysts. Overall, controlling biosynthesis parameters, such as electron donor, metal loading, and solution chemistry, enables tailoring of bio-Pd physicochemical and catalytic properties.

Boosted electrostatic interaction by surface sulfonation over Calixarene-TPE copolymer for prompt adsorption of cationic contaminates

Removal of cationic pollutants, including dyes, herbicides, and antibiotics from water is significant owing to their persistence, bioaccumulation, carcinogenicity, mutagenicity, and reproductive risks. In this paper, a calixarene-tetraphenyl ethylene containing copolymer adsorbent, named CP-TPE, was synthesized using the Suzuki-Miyaura coupling reaction between the resorcinol calixarene and tetraphenyl ethylene boric acid esters. Subsequently, the phenolic groups on the CP-TPE were further reacted with chlorosulfonic acid, resulting in a sulfonated product named CP-TPE-SO3H. The introduction of the sulfonate groups not only significantly improved the hydrophilicity of CP-TPE-SO3H but also enhanced the electrostatic interaction between CP-TPE-SO3H and cationic molecules, achieving an outstanding maximum adsorption capacity for paraquat (representative herbicide, 300.06 mg g−1) and tetracycline hydrochloride (representative antibiotic, 888.74 mg g−1), which surpassed the majority of reported polymeric adsorbents. Moreover, the k2 of CP-TPE-SO3H on TC (0.0407 g mg−1 min−1) reached the maximum value reported so far. This study demonstrated the significance and superiority of sulfonation modification in synthesizing POPs-based adsorbents, which can be potentially employed in real wastewater treatment.