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Imidazo[1,2-a]pyridines and especially their amide derivatives exhibit a wide range of favourable pharmacological properties. In this work, Pd-catalysed carbonylation was used for the first time for the introduction of the carboxamide moiety into positions 6 or 8. A recyclable Pd catalyst, with palladium immobilised on a supported ionic liquid phase decorated with pyridinium ions, was used efficiently for the conversion of 6- or 8-iodo derivatives to the products. In the case of 6-iodo derivatives, a competing mono- and double carbonylation could be observed in the reactions of aliphatic amines as nucleophiles, but under the proper choice of reaction conditions, good-to-excellent selectivities could be achieved towards either the corresponding amides or α-ketomides. The heterogeneous catalyst showed excellent recyclability and low Pd-leaching. [ABSTRACT FROM AUTHOR]

This paper presents the synthesis and application of a novel catalyst for carbon–carbon bond formations, comprising palladium immobilized on 2-(5-hydroxyquinolin-8-yl)-1H-benzo[d]imidazole-5-carboxylic acid modified superparamagnetic iron oxide nanoparticles (Pd@HQBI-SPION). The synthesis involved the attachment of HQBI ligands to SPION using APTES, followed by the immobilization of palladium. Characterization techniques, including FTIR, TEM, and magnetic measurements, confirmed the successful synthesis and structural integrity of Pd@HQBI-SPION. The catalytic activity of Pd@HQBI-SPION was evaluated in various carbon–carbon bond formation reactions, demonstrating high efficiency and reusability. 8 different derivatives bearing several electron withdrawing and electron donating functionalities were used as starting materials and the products were obtained in high isolated yields (75–97%). The catalyst exhibited excellent performance in one-pot synthesis of phenanthroline-dimedone polycyclic derivatives via C-alkylation followed by intramolecular O-alkylation of phenanthroline with dimedone. The products are obtained in high to excellent yields is described. This protocol presents a highly selective synthetic method for the construction of polycyclic aromatic compounds containing nitrogen and oxygen atoms. [ABSTRACT FROM AUTHOR]

Chiral N‐heterocyclic compounds are key structures in natural compounds and pharmaceuticals, and they serve as essential building blocks of functional materials. Catalytic asymmetric cycloaddition reactions represent one of the most efficient synthetic strategies for constructing optically active heterocycles. Cyclic sulfamidate imines have recently come to be extensively studied and widely utilized in both organocatalytic and transition metal‐catalyzed asymmetric cycloadditions, where they have been shown to provide various N‐fused‐heterocycles and spiro‐cycles exhibiting high efficiencies with excellent stereoselectivities. This review highlights recent advancements in catalytic asymmetric cycloadditions of cyclic sulfamidate imines for the stereoselective synthesis of biologically active sulfamidate‐containing heterocycles since 2012 while focusing on the diverse reactivities of cyclic sulfamidate imines and the mechanisms of chiral induction in catalysis. [ABSTRACT FROM AUTHOR]

The effects of time, temperature and catalyst concentration were investigated for an optimised condition of biphenyl synthesis by Suzuki-Miyaura cross-coupling reactions by Neolyst catalysts. The optimisation process was analysed using Box Behnken Face-Centred Experimental Design in Response Surface Methodology (RSM). The design was employed to derive a statistical model for the effect of parameters studied on the yield of biphenyl. The coefficient of determination, r2 was 0.9883% after model reduction. With an optimum time of 6.63 h, a temperature of 73°C and with minimum catalyst concentration of 0.013 mol% gives the optimum conditions for the maximum yield of biphenyl. [ABSTRACT FROM AUTHOR]

The [PdCl2(Xantphos)] complex, in comparison with several [PdCl2(P–P)] complexes having different diphosphine chelating ligands (P–P), is very active as a catalyst for the carbonylation of iodobenzene to methyl benzoate. The run conditions and the influence of several cocatalysts have been also studied to further improve the catalytic activity. The optimization of the catalytic system allowed to obtain TOFs of ca. 260,000 h−1. The addition of some additives able to reduce the possible catalyst deactivation allowed to increase the TOF of ca. 15%. The best positive results were obtained by adding reducing agents such as ferrocene, which leads to a TOF higher than 300,000 h−1. [ABSTRACT FROM AUTHOR]

Precisely controlling the product selectivity of a reaction is an important objective in organic synthesis. α‐Ketoamides are vital intermediates in chemical transformations and privileged motifs in numerous drugs, natural products, and biologically active molecules. The selective synthesis of α‐ketoamides from feedstock chemicals in a safe and operationally simple manner under mild conditions is a long‐standing catalysis challenge. Herein, an unprecedented TBD‐switched Pd‐catalyzed double isocyanide insertion reaction for assembling ketoamides in aqueous DMSO from (hetero)aryl halides and pseudohalides under mild conditions is reported. The effectiveness and utility of this protocol are demonstrated by its diverse substrate scope (93 examples), the ability to late‐stage modify pharmaceuticals, scalability to large‐scale synthesis, and the synthesis of pharmaceutically active molecules. Mechanistic studies indicate that TBD is a key ligand that modulates the Pd‐catalyzed double isocyanide insertion process, thereby selectively providing the desired α‐ketoamides in a unique manner. In addition, the imidoylpalladium(II) complex and α‐ketoimine amide are successfully isolated and determined by X‐ray analysis, confirming that they are probable intermediates in the catalytic pathway. [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]

An intermolecular annulation reaction of 2‐aryl‐1,3‐indandions with alkynes was reported using Pd(OAc)2 to access spirobi[indene]‐1,3‐diones. Under palladium catalysis, the substrates form a homocoupling dimer intermediate through a catalytic dehydrogenative cross‐coupling process. The palladium(II) species could come from dimer or 2‐aryl‐1,3‐indandion. Notably, this pathway is not typically observed in enol‐directed formal sp3 C−H functionalization/oxidative annulation palladium chemistry. This transformation provides a route to access a class of functionalized spiro carbocyclic indenes. [ABSTRACT FROM AUTHOR]

A novel fluorescent supramolecular polymer (named N3T) has been synthesized resoundingly, which can effectively identify trace amounts of Pd2+ in solution, and then a self-assembled supramolecular catalyst catalyst N3T-Pd was obtained. The N3T-Pd with spherical structure could be used for C–C coupling reactions in an eco-friendly aqueous medium. The catalyst was characterized by NMR, FT-IR, XPS, SEM and fluorescence spectra. The N3T-Pd has prominent stability and recyclability without any decrease of catalytic activity after least five cycles. Notably, the reaction degree of Pd2+ with the supramolecular polymer can be conformed by the fluorescence intensity of the supramolecular polymer. With that, the N3T detection limit (LOD) of Pd2+ was measured by fluorescent titration. Surprisingly, N3T can ultrasensitive detection of Pd2+, the limit of detection was 1.9 × 10−7 M. The self-assembly supramolecular palladium catalyst N3T-Pd has been developed as a novel and efficient catalyst for ligand-free C–C cross-coupling reactions in aqueous at room temperature. [ABSTRACT FROM AUTHOR]

1,2-Dihydroisoquinolines are important compounds due to their biological and medicinal activities, and numerous approaches to their synthesis have been reported. Recently, we reported a facile synthesis of trisubstituted allenamides via N-acetylation followed by DBU-promoted isomerization, where various substituted allenamides were conveniently synthesized from readily available propargylamines with high efficiency. In light of this research background, we focused on the utility of this methodology for the synthesis of substituted 1,2-dihydroisoquinolines. In this study, a palladium-catalyzed cascade cyclization–coupling of trisubstituted allenamides containing a bromoaryl moiety with arylboronic acids is described. When N-acetyl diphenyl-substituted trisubstituted allenamide and phenylboronic acid were treated with 10 mol% of Pd(OAc)2, 20 mol% of P(o-tolyl)3, and 5 equivalents of NaOH in dioxane/H2O (4/1) at 80 °C, the reaction proceeded to afford a substituted 1,2-dihydroisoquinoline. The reaction proceeded via intramolecular cyclization, followed by transmetallation with the arylboronic acid of the resulting allylpalladium intermediate. A variety of highly substituted 1,2-dihydroisoquinolines were concisely obtained using this methodology because the allenamides, as reaction substrates, were prepared from readily available propargylamines in one step. [ABSTRACT FROM AUTHOR]

We explored two methods for synthesizing Pd nanoparticles using three different carbide-derived carbon (CDC) support materials, one of which was nitrogen-doped. These materials were studied for oxygen reduction reaction (ORR) in 0.1 M KOH solution, and the resulting CDC/Pd catalysts were characterized using TEM, XRD, and XPS. The citrate method and the polyol method using polyvinylpyrrolidone (PVP) as a capping agent were employed to elucidate the impact of the support material on the final catalyst. The N-doping of the CDC material resulted in smaller Pd nanoparticles, but only in the case of the citrate method. This suggests that the influence of support is weaker when using the polyol method. The citrate method with CDC1, which is predominantly microporous, led to a higher degree of agglomeration and formation of larger particles in comparison to supports, which possessed a higher degree of mesoporosity. We achieved smaller Pd particle sizes using citrate and NaBH4 compared to the ethylene glycol PVP method. Pd deposited on CDC2 and CDC3 supports showed similar specific activity (SA), suggesting that the N-doping did not significantly influence the ORR process. The highest SA value was observed for CDC1/Pd_Cit, which could be attributed to the formation of larger Pd particles and agglomerates. [ABSTRACT FROM AUTHOR]

An efficient and stable palladium species catalyst immobilized on functionalized hyper–cross-linked polymers (HCPs-Pd) has been successfully developed and applied in the Suzuki–Miyaura coupling reaction of diverse types of aromatic halides with aryl boronic acid in this work. The results demonstrated that HCPs-Pd exhibited high catalytic activity, which benefited from the microporous structure of the catalyst guaranteed high dispersibility of active palladium, and high specific surface area, large pore volume, good chemical stability. Under optimal reaction conditions, 93.0% of biphenyl yield in the Suzuki–Miyaura reaction with bromobenzene (C6H5Br) and phenylboronic acid (C6H7BO2) as raw material was obtained. The good stability of the HCPs-II-Pd catalyst was verified by five cycles experiments. Perhaps this work provides new insights into the high-yield preparation of aromatic biphenyl compounds employing HCPs-Pd as an efficient and stable catalyst in the Suzuki–Miyaura reaction. [ABSTRACT FROM AUTHOR]

Catalytic formate decomposition under mild conditions is a promising strategy for hydrogen production as an efficient hydrogen carrier. Most of previous studies performed formate decomposition for hydrogen generation in liquid phase or using formate as a promoter for formic acid decomposition, which exhibits relatively low hydrogen energy density by mass. Here, we reported a gel-like formate system for catalytic hydrogen generation under mild conditions. A H 2 yield of 100% with hydrogen energy density by weight of 2.38 wt% was achieved, and the palladium catalyst shows high stability and recyclability for KCOOH gel decomposition. Moreover, the constructed gel-like formate filled in an aluminum cylinder could continuously and steadily supply hydrogen to a 12V/35W fuel cell to drive a LED display. This work may provide a new thought for safe hydrogen storage and production system for hydrogen energy usage in the future. • A gel-like KCOOH system was constructed for hydrogen generation under mild condition. • H 2 yield of 100% with hydrogen energy density by weight of 2.38 wt% was achieved. • The palladium catalyst shows high stability for decomposition of KCOOH gel. • The magnified KCOOH gel can be applied on a fuel cell system. [ABSTRACT FROM AUTHOR]

Suzuki−Miyaura cross‐coupling reactions are used to modify the tyrosine residues on Bombyx mori silkworm silk proteins using a water‐soluble palladium catalyst. First, model reactions using tyrosine derivatives are screened to determine optimal reaction conditions. For these reactions, a variety of aryl boronic acids, solvents, buffers, and temperature ranges are explored. Qualitative information on the reaction progress is collected via high‐performance liquid chromatography (HPLC), mass spectrometry (MS), and nuclear magnetic resonance (NMR). Optimized reactions are then applied to silk proteins. It is demonstrated the ability to modify silk fibroin in solution by first iodinating the tyrosine residues on the protein, and then carrying out Suzuki‐Miyaura reactions with a variety of boronic acid derivatives. Modification of silk is confirmed with NMR, ion‐exchange chromatography (IEC), UV‐vis, and infrared spectroscopy (IR). [ABSTRACT FROM AUTHOR]

In order to increase the catalytic activity of the Pd(II)-complexes in the alcoxycarbonylation of 1-olefins, the presence in solution of a strong Brönsted acid together with a phosphine ligand is usually required. From an industrial point of view, such two additives, however, influenced the sustainability of the process mainly caused by the related corrosion of the reaction vessel and the toxicity of the phosphine ligand. In this paper, the methoxycarbonylation of 1-octene has been efficiently carried out by using the [Pd(TsO)2(PPh3)2]/FeCl3 catalyst system. The catalyst is very active also without addition of PPh3, reaching the TON of ca. 1300 (mol/mol) in 2 hours by using the Fe(III)/Pd(II) = 400/1 (mol/mol) system. Such value is higher than the values obtained by using the traditional strong Brönsted acid TsOH or other Lewis acid such as AlCl3, in the presence of PPh3. The reaction takes place with the formation of two isomeric products of linear and branched structures with a yield towards the linear isomer of ca. 80%. [ABSTRACT FROM AUTHOR]

This document provides detailed information on the synthesis and characterization of three chemical compounds obtained through a palladium-catalyzed elimination reaction. The compounds were synthesized using specific reagents and conditions, and their structures were confirmed using various analytical techniques. The document also acknowledges the assistance of the Instrumental Analysis Center at Osaka University and includes supporting information for further reference. This information can be valuable for researchers studying these compounds or related topics. [Extracted from the article]

Herein we describe Pd‐catalyzed cross‐coupling reaction of α‐pinene derivative – pinacarvone O‐methyl oxime (1) with aryl halides (2). Surprisingly, the formation of the C−C coupling product was accompanied by an unexpected opening of the pinene bicyclic structure. The (Z)‐2‐aryl‐4,4,5‐trimethylcyclohexa‐2,5‐dien‐1‐one O‐methyl oxime (3) was formed as the resulting product. The reaction conditions of the developed synthetic procedure were carefully optimized and the reaction mechanism was supposed on the basis of data obtained by structural and computational methods. [ABSTRACT FROM AUTHOR]

N-(4-hydroxyphenyl)acetamide (commonly named paracetamol or acetaminophen) is a target molecules for many industries that produce chemicals for pharmaceutical applications. The industrial processes, however, use multistep procedures with low overall yield and/or severe drawbacks and problems in terms of sustainability. In the present paper, a one-pot synthesis is proposed based on the reductive carbonylation of nitrobenzene catalyzed by Pd(II)-complexes. Usually, such a reaction leads to a mixture of different products, including aniline, 4-aminophenol and 1,3-diphenylurea. However, the selectivity towards the possible products strongly depends by the ligands on the Pd(II)-catalyst, but also by the nature of the solvent. According to this, we have found that when the reaction was carried out in dilute acetic acid as a solvent, the [PdCl2(dppb)] catalyst precursor leads in one pot to N-(4-hydroxyphenyl)acetamide. Under optimized reaction conditions, it was possible to produce N-(4-hydroxyphenyl)acetamide with a 85 mol % of selectivity in ca. 5 h. [ABSTRACT FROM AUTHOR]

Beyond the scope of classical Tsuji‐Trost reaction, an alkene bearing a remote leaving group is not considered as a potential substrate for allylation. The concept of migratory Tsuji‐Trost reaction focuses on the transformations with this type of substrates. Two pathways including olefin migration and leaving group migration to form typical allyl intermediate for following substitution have been explored to demonstrate the feasibility of this new concept. [ABSTRACT FROM AUTHOR]

In the palladium-catalyzed cross-coupling of potassium pentafluorophenyltrifluoroborate with aryl chlorides in the presence of the precursor of SIMes carbene, the yields of pentafluorobiphenyls decrease, whereas the yield of 2,3,4,5,6-pentafluoro-4'-methylbiphenyl from 4-bromotoluene under the same conditions increases. An explanation for this phenomenon and for the intensification of the side hydrodeboration reaction of the initial borate has been proposed. [ABSTRACT FROM AUTHOR]

A new set of microporous organic polymers (POPs) containing diphosphine derivatives synthesized by knitting via Friedel–Crafts has been attained. These amorphous three-dimensional materials have been prepared by utilizing diphosphines, 1,3,5-triphenylbenzene, and biphenyl as nucleophile aromatic groups, dimethoxymethane as the electrophilic linker, and FeCl3 as a promoting catalyst. These polymer networks display moderate thermal stability and high microporosity, boasting BET surface areas above 760 m2/g. They are capable of coordinating with palladium acetate, using the phosphine derivative as an anchoring center, and have proven to be highly efficient catalysts in Suzuki–Miyaura coupling reactions involving bromo- and chloroarenes under environmentally friendly (using water and ethanol as solvents) and aerobic conditions. These supported catalysts have achieved excellent turnover numbers (TON) and turnover frequencies (TOF), while maintaining good recyclability without significant loss of activity or Pd leaching after five consecutive reaction cycles. [ABSTRACT FROM AUTHOR]

Adipic acid (AA), an important precursor to produce nylon‐6, nylon‐6,6, and polyurethanes, can be synthesized from biomass‐derived 1,6‐hexanediol (HDO). Herein, we examined the selective oxidation of 1,6‐hexanediol to adipic acid over Pd/support (support‐ Rice husk ash (RHA), TiO2, C, ZnO, Al2O3, La2O3, Mg(OH)2, and hydroxyapatite (HAP)) catalyst in water at 70 °C under base‐free conditions. Pd/HAP exhibited high catalytic activity among the catalysts explored, affording adipic acid (AA) selectively in 89 % yield with complete conversion of HDO. Investigating these Pd/support catalysts and several control experiments inferred that the basicity of the HAP support concertedly with Pd nanoparticle participated in achieving efficient aerial oxidation of HDO to AA, and hence avoided the need for any additional base additives. Advantageously, Pd/HAP exhibited high activity for gram‐scale reactions and long‐term stability during reusing the catalyst for several cycles without any considerable loss in the catalytic activity. [ABSTRACT FROM AUTHOR]

Two kinds of oxide-zeolite composite support, Ce-beta and Zr-beta were prepared by a simple wet impregnation method and adopted for the preparation of palladium-based catalysts for catalytic oxidation of methane. The Pd/6.8Zr-beta catalyst showed superior methane oxidation performance, achieving T 50 and T 90 of 417 °C and 451 °C, respectively, together with robust hydrothermal stability. Kinetic analysis has shown that incorporating Zr into the catalyst significantly enhanced its efficiency, nearly tripling the turnover frequency (TOF) for methane combustion compared to the Pd/beta catalyst. This enhanced performance was attributed to the dispersion of Zr on the zeolite surface, which not only promoted the formation of active PdO sites but also helped maintain the high Pd2+ content via facilitating the oxygen migration during the reaction, thus improving both the catalyst's activity and stability. In the Pd/8.6Ce-beta catalyst, doped CeO 2 tended to aggregate in the zeolite's pores, adversely affecting the catalyst's efficiency. This aggregation promoted the formation of inactive Pd4+ species, a result of the enhanced metal-support interaction. This finding is critical for understanding the implications of dopant selection in the design of high-activity methane oxidation catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel method for chemodivergent deoxygenative- and alkoxy-carbonylation of alcohols. • With boronic acids as the reaction partner, esters and ketones can be produced selectively. • This protocol features excellent regioselectivity and broad substrate scope. • Highly base-sensitive boronic acid substrates can also be applied under base-free conditions. A method for the chemodivergent deoxygenative- and alkoxy-carbonylation of alcohols with boronic acids via palladium catalysis has been developed. Manipulation of the divergent selectivities depend on simply changing the choice of activators. While a carbodiimide activator promoted the formation of ketones through deoxygenative carbonylation, selectivity for esters via alkoxy carbonylation was observed with an azo activator. Notably, in addition to the broad substrate scope, this base-free strategy enables the use of highly base-sensitive boronic acid substrates. This study contributes to the art of chemoselectivity control in carbonylation chemistry. [ABSTRACT FROM AUTHOR]

In this work, comparative testing of the activity of low-percentage palladium and palladium-nickel catalysts supported on activated diatomite with a commercial nickel catalyst from BASF was carried out in the process of hydrogenation of polyalphaolefins (PAO-4). It has been found that palladium catalysts carry out the process under milder conditions, demonstrate higher activity compared to nickel catalysts, significantly reduce the process time, and provide a higher degree of hydrogenation. The activity of bimetallic catalysts is lower than that of monometallic palladium catalysts. Furthermore, Ni exhibits a reaction temperature of at least 150 °C, while Pd is at least 110 °C. If nickel is a single-use catalyst, then when palladium is used 5 times remains an excellent catalytic activity. Catalyst activity is related to the form of adsorbed hydrogen, and on Pd catalyst hydrogen is weakly bound form, while on Ni hydrogen is strongly bound form. The physicochemical characteristics of catalysts and polyalphaolefin oils also have been determined. [ABSTRACT FROM AUTHOR]

Subsequently, the effects of different Cu reagents on the yields of B 5a b and B 6a b were examined under the reaction condition using Pd(PPh SB 3 sb ) SB 4 sb (entries 4-11). Keywords: dihydropyrimidine; fully substituted 2-aryldihydropyrimidine; Pd-catalyzed/Cu-mediated reaction; Liebeskind-Srogl-type cross-coupling reaction; palladium catalyst; copper reagent; aryltributylstannanes; heteroaryltributylstannanes EN dihydropyrimidine fully substituted 2-aryldihydropyrimidine Pd-catalyzed/Cu-mediated reaction Liebeskind-Srogl-type cross-coupling reaction palladium catalyst copper reagent aryltributylstannanes heteroaryltributylstannanes 1996 2004 9 06/16/23 20230704 NES 230704 Dihydropyrimidines (DPs) show a wide range of biological activities suitable for medicinal applications, namely, they display calcium channel inhibitory, [1] anticancer, [3] antibacterial, [5] antifungal, [6] anti-human immunodeficiency virus (HIV), [7] antimalarial, [8] anti-inflammatory, [9] and antioxidation [10] activities. The reaction proceeds smoothly using a low amount (0.5 mol%) of Pd(PPh SB 3 sb ) SB 4 sb and the easily accessible and inexpensive reagent CuBr. Fully substituted 2-aryldihydropyrimidine, Pd-catalyzed/Cu-mediated reaction, Liebeskind-Srogl-type cross-coupling reaction, palladium catalyst, copper reagent, dihydropyrimidine, aryltributylstannanes, heteroaryltributylstannanes. [Extracted from the article]

[Display omitted] • A new palladium-catalyzed redox-neutral dicarbonylation of terminal alkynes has been reported. • Hydroxylamine acts as both a nucleophile and a potential oxidant. • Maleimides were synthesized in moderate yields under relatively mild conditions. • A new idea for oxidative carbonylation reactions. A palladium-catalyzed redox-neutral dicarbonylation of terminal alkynes has been reported, in which hydroxylamine acts as both a nucleophile and a potential oxidant. Maleimides were synthesized in moderate yields under relatively mild conditions while avoiding the addition of equivalent oxidants. This reaction process involves two key steps: the addition of Pd-H to the terminal alkyne, and the hydroxylamine ester intermediate play the role of an internal oxidant via nucleophilic attack by hydroxylamine. This reaction has a wide range of functional group compatibility, and this internal oxidation reaction process also provided a new idea for other oxidative carbonylation reactions. [ABSTRACT FROM AUTHOR]

A series of Schiff‐base functional groups modified MCM‐41 materials have been synthesized and used as the supports of palladium species. The chemical structures of MCM‐41 functionalized by nine Schiff‐base functional groups were characterized by Fourier transform infrared spectroscopy (FT‐IR), whereas their grafting densities of functional groups were achieved from the results of thermogravimetric analysis (TGA) and elemental analysis (EA). Small angle powdered X‐ray (SAX) patterns demonstrate that the ordered mesoporous structures of MCM‐41 were well retained after modification of functional groups and immobilization of Pd2+ cations. Moreover, the regular mesoporous structures of supports and homogeneous dispersions of Pd2+ cations were characterized by transmission electron microscopy (TEM). The positron annihilation lifetime spectroscopic (PALS) results revealed that the electronic and steric factors of functional groups could affect the o‐Ps annihilation properties of support Pd2+ cations. Meanwhile, the catalytic activities of these supported Pd2+ cations chelated by different functional groups were determined by the Heck reaction of iodobenzene with n‐butyl acrylate. At last, the catalytic activities of these supported Pd2+ cations were linearly correlated to their o‐Ps annihilation properties. This result demonstrates that the catalytic activities of supported Pd2+ cations chelated by different functional groups can be readily determined by the o‐Ps annihilation, which can be potentially used in the design and preparation of highly active palladium catalysts. [ABSTRACT FROM AUTHOR]

An efficient and facile synthetic procedure has been developed for the synthesis of novel series of Bis-6-aryl-imidazo[1,2-a]pyridine-2-carboxamide containing 3,3'-((oxybis(ethane-2,1-diyl))bis(oxy))bis(propan-1-amine) derivatives (6a-6j). An application of the Palladium catalyzed Suzuki reaction on amine-(CH2)3-PEG3-(CH2)3-amine linked 6-bromo imidazo[1,2-a]pyridine-2-carboxamide was reported and their products are discussed. The reaction was optimized through numerous catalytic conditions for this strategy, and it was fixed with the best approach having advantages of less reaction time, higher degree of yield, most consumption of starting material, and selection of best catalyst for the success of the reaction. The ideal spectroscopic characterization (PMR, CMR, IR and MS) have been utilized for the finalization of the synthesized adducts. [ABSTRACT FROM AUTHOR]

The main pathways of liquid-phase hydrogenation of 5-ethenylbicyclo[2.2.1]hept-2-ene (5-vinyl-2-norbornene, VNE) in the presence of PK-25 palladium catalyst (Pd/γ-Al2O3, 0.25% Pd) were studied. All the reaction products were identified, and the material balance was examined. The effect of the prevalent adsorption of the norbornene double bond on the Pd active site (AS) was confirmed. The parallel-consecutive scheme of the process mechanism, based on the set of experimental and theoretical data, was suggested. It involves the successive substrate hydrogenation and significant role of the isomerization of the vinyl group into the ethylidene group in intermediates on AS in a hydrogen atmosphere. The reaction is zero-order in a wide interval of initial VNE concentrations. An adequate kinetic model of the process, based on the Langmuir–Hinshelwood approach and the concept of multiple adsorption of substrates on one AS, was developed. Five steps, including two parallel steps, significantly contribute to the reaction rate. Their rate constants and the adsorption constants of AS complexes with unsaturated compounds were estimated. [ABSTRACT FROM AUTHOR]

Polar-functionalized polyolefins are high-value materials with improved properties. However, their feedstocks generally come from non-renewable fossil products; thus, it requires the development of renewable bio-based monomers to produce functionalized polyolefins. In this contribution, via the Pd-catalyzed telomerization of 1,3-butadiene and three types of bio-based alcohols (furfuryl alcohol, tetrahydrofurfuryl alcohol, and solketal), 2,7-octadienyl ether monomers including OC8-FUR, OC8-THF, and OC8-SOL were synthesized and characterized, respectively. The copolymerization of these monomers with ethylene catalyzed by phosphine–sulfonate palladium catalysts was further investigated. Microstructures of the resultant copolymers were analyzed by NMR and ATR-IR spectroscopy, revealing linear structures with incorporations of difunctionalized side chains bearing both allyl ether units and polar cyclic groups. Mechanical property studies exhibited better strain-at-break of these copolymers compared to the non-polar polyethylene, among which the copolymer E-FUR with the incorporation of 0.3 mol% displayed the highest strain-at-break and stress-at-break values of 940% and 35.9 MPa, respectively. [ABSTRACT FROM AUTHOR]

A new MOF‐supported heterogeneous palladium catalyst Pd/NBB‐1 has been synthesized successfully through the effective metal metathesis between Pd(CF3COO)2 and NBB‐1. NBB‐1 is a two‐dimensional zinc metal‐organic framework constructed from 2‐aminoterephthalate (NH2−H2BDC) and 2,2′‐bipyridine‐5‐carboxylate (HBPC) by solvothermal method. The replacement efficiency of Pd(II) to Zn(II) is up to 72% after only 24 hours, which is beneficial to the catalytic application. Pd/NBB‐1 with a low loading of 2 mol% works efficiently in the 1,4‐addition reaction of arylboronic acids with α,β‐unsaturated ketones in air, and its catalytic activity keeps unchanged after 3 reaction cycles. This work provides a new strategy to effectively prepare supported noble metal/MOF catalysts, which would further increase the practical applications of metal‐organic frameworks. [ABSTRACT FROM AUTHOR]

[Display omitted] • La-doped wrinkled silica-supported Pd catalysts for selective furfural hydrogenation. • Parallel adsorption geometry of furfural facilitates furan and carbonyl conversion. • Strong interaction between Pd and La species leads to exceptional catalytic activity. The catalytic hydrogenation of furfural (FF) to tetrahydrofurfuryl alcohol (THFAL) is complicated by competing hydrogenation reactions involving the carbonyl group and furan ring. To address this challenge, we developed Pd/xLa@wrinkled silica (Pd/xLa@KCC) catalysts exhibiting excellent efficiency via the optimization of La/Si molar ratios, improved Pd dispersion, and stabilization of partially oxidized Pd particles (Pdδ+). These catalysts were designed for the selective hydrogenation of FF to THFAL. Pd/0.2La@KCC, characterized by a high level of oxygen defects, good basicity, and abundant Pdδ+ species, achieved complete conversion and 91.2 % THFAL selectivity at 45 °C within 6 h. Pd/0.2La@KCC exhibited a THFAL formation rate of 100.9 mmol/g/h, 10.8 times higher than that of Pd/0.02La@KCC. Improved Pd dispersion increased the available metallic surface area for H 2 dissociations, whereas abundant Lewis-base sites and Pdδ+ species served as adsorption sites for the carbonyl group and furan ring, respectively. The catalyst facilitated the activation and conversion of the furan ring and carbonyl group to THFAL owing to the parallel adsorption geometry of FF. This approach highlights the importance of the surface characteristics of the catalyst for achieving exceptional selectivity and efficiency. Our findings provide valuable insights into the development of advanced catalysts exhibiting excellent selectivity for biomass-derived chemicals. [ABSTRACT FROM AUTHOR]

Supported palladium catalysts exhibit exceptional catalytic activity in methane combustion, yet they still suffer from rapid deactivation due to sintering during reaction conditions. In this study, we reported supported palladium catalysts on siliceous MFI zeolite with abundant silanol nests, which served as highly effective anchoring sites for stabilizing PdO x nanoparticles. The innovative Pd/S-1-OH catalyst demonstrated remarkable catalytic activity in methane combustion, achieving a low T 50 of 295 °C. Additionally, this catalyst demonstrated extremely high stability even after severe hydrothermal aging at 750 °C for 16 hours, and maintained long-term stability in wet methane combustion for 100 hours. Various characterizations confirmed the anchoring effect of silanol nests for PdO x nanoparticles, primarily attributed to the robust binding energy between PdO x nanoparticles and silanol nests. Furthermore, the engineering of silanol nests on zeolite through desilication significantly improved the stability of Pd/silicalite-1, thereby benefiting for the development of palladium/zeolite catalysts with exceptional stability. [Display omitted] • Silanol nests on zeolite serve as anchoring sites for stabilization of PdO x nanoparticles. • Silanol nests anchored PdO x nanoparticles on the external surface of S-1-OH zeolite. • Pd/S-1-OH catalyst showed remarkable catalytic activity and stability in methane combustion. • The robust binding energy between PdO x nanoparticles and silanol nests was demonstrated. [ABSTRACT FROM AUTHOR]

The Pd/Cu-catalyzed Sonogashira reaction of (E,E)-bis(2-bromovinyl) selenide and (E,E)-bis(1-bromo-1-hexen-2-yl) selenide with terminal alkynes was found to proceed at room temperature involving both bromine atoms and the selanyl function. As a result, new bis-(1,3-enynyl) selenides and enediyne hydrocarbons are formed with a complete retention of the stereoconfiguration of the initial selenides. Due to steric hindrances in the cross-coupling at the selenyl function in the case of (E,E)-bis(1-bromo-1-hexen-2-yl) selenide, the second process is realized to a lesser extent than with unsubstituted (E,E)-bis(2-bromovinyl) selenide. [ABSTRACT FROM AUTHOR]

A direct synthesis method of efficient and mild water‐resistant organoindium reagents and their cross‐coupling reactions with aryl iodide by palladium‐catalyzed was described. At room temperature, organic indium reagents were mediated by AgI, and water‐tolerant alkyl indium reagents were directly and efficiently synthesized. The cross‐coupling reaction of organic indium reagents with various aryl halides could perform smoothly with palladium catalysis. The expected products were obtained in moderate to good yields, and the best yield can reach 99 %. These reactions are promising for their high reactivity, broad applicability, and functional group tolerance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel palladium-catalyzed domino carbonylative cyclization. • Carbonylative cyclization of alkene-tethered indole derivatives with alkyne-tethered nucleophiles. • Several pharmaceutical and bioactive molecule related compounds were also suitable substrates here. A novel palladium-catalyzed domino carbonylative cyclization of alkene-tethered indole derivatives with alkyne-tethered nucleophiles has been developed, which provides a straightforward and efficient platform for the rapid construction of functionalized heterocycles. By using benzene-1,3,5-triyl triformate (TFBen) as the CO source, this domino reaction proceeded smoothly with the consecutive formation of three C C bonds and one C-X bond to furnish a variety of biologically relevant indolo[2,1- a ]isoquinoline-indole and indolo[2,1- a ]isoquinoline-dihydrobenzofuran derivatives in good yields. [ABSTRACT FROM AUTHOR]

Liquid-phase hydrogenation of 5-vinylbicyclo[2.2.1]hept-2-ene (5-vinyl-2-norbornene, VNE) existing as a mixture of endo- and exo-isomers in the presence of a palladium catalyst (0.25% Pd/γ-Al2O3, or PC-25) is a complex consecutive-parallel process proceeding via the formation of (endo/exo)-2-vinylnorbornanes. Subsequent hydrogenation of the latter is preceded by quantitative isomerization of the vinyl group to the ethylidene one. The mechanism of the phenomenon was studied experimentally and theoretically. It was established that isomerization of 2-vinylnorbornanes to 2-ethylidenenorbornanes requires the presence of palladium (as the active component of the catalyst) and hydrogen in the reaction system. All reaction products were identified and the material balance of the process was studied. According to DFT PBE/SBK quantum chemical calculations, migration of the multiple bond in 2-vinylnorbornanes on the Pd(111) face of the model cluster Pd21(H)2 is of allylic character. [ABSTRACT FROM AUTHOR]

Herein, a sustainable route to novel aromatic monomer, dimethyl 1,2,3,4-tetrahydro-1,4-methanonaphthalene-5,8-dicarboxylate, was developed, in which dimethyl muconate and norbornene used as the diene and dienophile undergo Diels-Alder reaction followed by dehydrogenation. The polycyclic cycloadduct, octahydro-1,4-methanonaphthalene-5,8-dicarboxylate, could be synthesized without catalyst. The activated carbon modified with sulfuric acid generated more oxygen-containing groups, stronger acidity and more acidic sites. Highly dispersed palladium metal particles with an average particle size of about 1.0 nm exhibited excellent activity in the dehydrogenation reaction and the yield of target product reached 73.8 %. • A sustainable route to synthesis novel polycyclic aromatic monomer was developed. • Norbornene smoothly underwent Diels-Alder reaction with biomass-derived muconate. • Pd/AC-H2SO4 exhibited excellent catalytic dehydrogenation performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A general and efficient protocol for the synthesis of thioesters-functionalized 2H-benzopyrans. • A new palladium-catalyzed one-pot cyclization/thiocarbonylation reaction of propargyl ethers with sulfonyl chlorides. • Both aryl and alkylsulfonyl chlorides were suitable sulfur sources. • Mo(CO) 6 has been used as convenient CO source and reductant. • A wide range of 2 H -benzopyrans bearing thioester were obtained in moderate to good yields. A general and efficient protocol for the synthesis of thioesters-functionalized 2 H -benzopyrans has been developed through a palladium-catalyzed one-pot cyclization/thiocarbonylation reaction of propargyl ethers with sulfonyl chlorides as promising and easily accessible sulfur sources. The reaction showed good compatibility towards versatile functional groups, both aryl and alkylsulfonyl chlorides were well tolerated. Without any external reductant, using Mo(CO) 6 as a convenient CO source, a wide range of 2 H -benzopyrans bearing thioester as an attractive functional group were obtained in moderate to good yields. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new method for the synthesis of HFIP esters-containing 2 H -benzopyrans. • Palladium-catalyzed one-pot cyclization/carbonylation reaction of substituted propargyl ethers with HFIP. • Using formic acid as the CO precursor. An efficient and straightforward procedure for the synthesis of HFIP esters-containing 2 H -benzopyrans has been established through palladium-catalyzed one-pot cyclization/carbonylation reaction of substituted propargyl ethers with HFIP by using formic acid as the CO precursor. A diverse set of 2 H -benzopyrans have been formed with HFIP esters as attractive functional groups in moderate to excellent yields. This protocol features broad substrate scopes and no manipulation of toxic CO gas. [ABSTRACT FROM AUTHOR]

A method for mild and efficient hydrodeoxygenation of aryl sulfonates is presented. Though a rational and careful adjustment of the stereoelectronic nature of bidentate phosphine ligands, the reaction could proceed very rapidly and efficiently at room temperature with 1 mol% Pd(OAc) 2 as precatalyst and 2 mol% bis[(di- tert -butylphsophanyl)methyl]-substituted diphosphines as ligands, giving the products in high to excellent yields (71–98 %). The method showed a broad substrate scope including various fused and unfused aryl triflates, and delocalized aryl tosylates and mesylates. Moreover, the reaction could be reliably carried out at gram scale with only 0.1 mol% Pd(OAc) 2 and 0.2 mol% ligand loading and tolerates a rich variety of reducible and Pd-sensitive functionalities. These advantages make the method more general and practical for the hydrodeoxygenation of aryl sulfonates. [Display omitted] • A room temperature hydrodeoxygenation of aryl sulfonates with 1 mol% Pd(OAc) 2 and 2 mol% diphosphines as ligands. • Broad substrate scope including various fused and unfused aryl triflates, and delocalized aryl tosylates and mesylats. • The reaction could be reliably carried out at gram scale with only 0.1 mol% Pd(OAc) 2 and 0.2 mol% ligand loading. [ABSTRACT FROM AUTHOR]

Our group introduced a green protocol for the Pd(OAc)2- or NiCl2-catalyzed P–C coupling reaction of aryl halides and various > P(O)H-compounds under MW conditions without directly added P-ligands. The reactivity of a few aryl derivatives in the Pd(OAc)2-catalyzed Hirao reaction was also studied. An induction period was observed in the reaction of bromobenzene and diphenylphosphine oxide. Finally, the less known copper(I)-promoted P–C coupling reactions were investigated experimentally. The mechanism was explored by quantum chemical calculations. [ABSTRACT FROM AUTHOR]

Recently, we have reported the preparation of a silk fibroin‐supported Palladium catalyst (Pd/SF) and its use in the Suzuki‐Miyaura cross‐coupling of aryl iodides. Since its synthetic applicability and structural features are still far from being fully explored, a deeper investigation is reported here. Pd/SF is tested as a catalyst for the Suzuki‐Miyaura and Ullmann coupling reactions of aryl chlorides, in H2O/EtOH solvent mixture under atmospheric conditions. Starting from the analysis of the products of the Pd/SF promoted Ullmann reactions of poly‐haloarenes, we can hypothesize the existence of catalytic pockets where monoatomic palladium species can form stable complexes with SF. To shed light on this hypothesis, Pd/SF is characterized by Wide‐Angle X‐ray Scattering (WAXS) analysis, which supports the supposition of catalytic pockets. Finally, using a computational model developed by Molecular Mechanic Energy Minimization we have estimated the dimension of the catalytic pocket of Pd/SF (about 15 Å), in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Liquid-phase hydrogenation of bicyclo[2.2.1]hepta-2,5-diene (norbornadiene, ND) proceeds in the presence of an industrial palladium catalyst Pd/γ-Al2O3 (PK-25) in an n-heptane solution at 76°C via consecutive formation of bicyclo[2.2.1]hept-2-ene (norbornene, NE) and bicyclo[2.2.1]heptane (norbornane, NA), as well as tricyclo[2.2.1.02,6]heptane (nortricyclane, NT) as a minor product. The reaction products were identified, the main routes were determined, and the material balance was studied. Preferable adsorption of ND at the active palladium site over adsorption of other components of the system was confirmed. A parallel-serial scheme of the process mechanism was proposed based on the sum of experimental and theoretical data. Zero order kinetics was observed in a wide range of initial substrate concentrations. The apparent rate constants of each stage were measured. A detailed kinetic model was developed based on the Langmuir–Hinshelwood approach, assuming multiple adsorption of substrates at a single active site of the heterogeneous catalyst. The model adequately describes the available experimental data using the proposed mechanism of ND hydrogenation. The possibility of a "cocktail" mechanism for the given reaction was discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A general Pd/g-C3N4 catalyzed carbonylative cyclization of 2-bromonitrobenzenes and alkynes. • Mo(CO) 6 as both the CO surrogate and the reductant. • Nitroarenes as the nitrogen source. • Good yields of quinolin-4(1 H)-ones products. • Catalyst is recyclable. A palladium supported on graphitic carbon nitride (Pd/g-C 3 N 4) catalyzed carbonylative cyclization of 2-bromonitrobenzenes and alkynes has been developed for the expedite construction of quinolin-4(1 H)-one scaffolds. By using a low loading heterogeneous palladium catalyst, Mo(CO) 6 as both the CO surrogate and the reductant, and nitroarenes as the nitrogen source, the reaction proceeded well to give a variety of quinolin-4(1 H)-ones in good to excellent yields. [ABSTRACT FROM AUTHOR]

A series of 3-amino-5-(1,4-dioxo-1,4-dihydronaphthalen-2-ylamino)benzoic acid derivatives were synthesized by the Michael addition of 1,4-naphthoquinone and 3,5-diaminobenzoic acid followed by the Suzuki coupling reaction. The derivatives of compound 2 were integrated, exposing it to benzolyation by an assortment of acid chlorides. Among the synthesized compounds, compounds 3b, 3c and 3d displayed better IC50 value of cytotoxicity (against HeLa) when compared with other derivatives. All the IC50 esteems were compared with the standard drug doxorubicin. DPPH and ABTS evaluation procedures are employed to assess the antioxidant activity. The compound 3d exhibited the highest inhibition of 75% and 77% in the DPPH and ABTS antioxidant activity evaluation, respectively. [ABSTRACT FROM AUTHOR]

Synthesis of fused tricyclic oxazolo[4,5‐c]quinolines from 2‐iodo‐N‐((2‐phenyloxazol‐4‐yl)methyl)anilines via intramolecular C−H heteroarylation in the presence of palladium catalyst under ligand free conditions has been disclosed. Various substituted 2‐iodo‐N‐((2‐phenyloxazol‐4‐yl)methyl)anilines are well tolerated and furnished the products in good yields. The synthetic utility of the resulting molecules has been demonstrated. This method features broad substrate scope, mild reaction conditions, good functional group tolerance, and scalability. [ABSTRACT FROM AUTHOR]

The liquid-phase hydrogenation of 5-ethenylbicyclo[2.2.1]hept-2-ene (5-vinyl-2-norbornene, VNE) in the presence of the palladium catalyst Pd/γ-Al2O3 (PC-25) in an n-heptane medium at 76 °C was studied. The hydrogenation proceeds via a complicated mechanism through (exo/endo)-2-vinylnorbornanes and (Z/E)-2-ethylidenenorbornanes to form (exo/endo)-2-ethylnorbornanes. The reaction products were identified, the main reaction routes were determined, and the material balance was studied. The isomerization of (exo/endo)-2-vinylnorbornanes to (Z/E)-2-ethylidenenorbornanes with the conversion close to 100% was found for the reaction in a hydrogen atmosphere. The molar ratios of the stereoisomers of the substrate and of the intermediate and final hydrogenation products are retained at all steps of the process. The parallel-sequential mechanism was proposed for the process. The zero kinetic time order with respect to VNE was established in a wide range of its initial concentrations. [ABSTRACT FROM AUTHOR]

We developed a one-pot, two-stage synthetic route to access 9-aminoacridines involving a Buchwald-Hartwig coupling reaction followed by acid-mediated cycloaromatization. This one-pot reaction affords pharmaceutically valuable 9-aminoacridines from readily available 2-bromobenzonitriles and arylamines. The reaction was easily scaled-up to gram quantities. This methodology was extended to the preparation of various useful 9-aminoacridines, and further exemplified by the synthesis of 9-amino-6-chloro-2-methoxy acridine, an important scaffold of marketed drugs such as mepacrine and quinpramine. [ABSTRACT FROM AUTHOR]