Search

Olefin hydrogenation is one of the most important transformations in organic synthesis. Electrochemical transition metal‐catalyzed hydrogenation is an attractive approach to replace the dangerous hydrogen gas with electrons and protons. However, this reaction poses major challenges due to rapid hydrogen evolution reaction (HER) of metal‐hydride species that outcompetes alkene hydrogenation step, and facile deposition of the metal catalyst at the electrode that stalls reaction. Here we report an economical and efficient strategy to achieve high selectivity for hydrogenation reactivity over the well‐established HER. Using an inexpensive and bench‐stable nickel salt as the catalyst, this mild reaction features outstanding substrate generality and functional group compatibility, and distinct chemoselectivity. In addition, hydrodebromination of alkyl and aryl bromides could be realized using the same reaction system with a different ligand, and high chemoselectivity between hydrogenation and hydrodebromination could be achieved through ligand selection. The practicability of our method has been demonstrated by the success of large‐scale synthesis using catalytic amount of electrolyte and a minimal amount of solvent. Cyclic voltammetry and kinetic studies were performed, which support a NiII/0 catalytic cycle and the pre‐coordination of the substrate to the nickel center. [ABSTRACT FROM AUTHOR]

Herein, we report a mild and practical method for the deuteration of alkyl and aryl bromides by a thiyl radical catalyst and halogen-atom transfer (XAT) using disulfides and silanes under visible-light irradiation. In this study, various organic bromides such as 1°, 2°, and 3°-alkyl bromides and aryl bromides were converted to deuterated products in good to excellent yields and D-incorporation. [ABSTRACT FROM AUTHOR]

A C(sp3)–C(sp3) cross coupling approach based on an iridium-photocatalytic radical process has been developed enabling the synthesis of various α-alkylated aldehydes from easily available/synthesized alkyl bromides and trialkyl amines under mild photocatalytic conditions. The synthesized aldehydes are also explored as a functional handle for various useful products such as carboxylic acid, alcohol and N-heterocycle synthesis. [ABSTRACT FROM AUTHOR]

We have developed a novel Ni-catalyzed reductive cross-coupling reaction of aryl bromides and alkyl iodides via a photoactive electron donor–acceptor (EDA) complex. This photo-induced process enables the efficient construction of C(sp2)–C(sp3) bonds in the absence of an external photocatalyst. Electronically and structurally diverse aryl bromides, as well as secondary and primary alkyl iodides could undergo this transformation smoothly. Natural product derivatives were employed successfully, and UV-vis spectroscopy was utilized to gain mechanistic insight. [ABSTRACT FROM AUTHOR]

A novel and efficient method for functionalizing organosulfones has been established, utilizing a visible-light-driven intermolecular radical cascade cyclization of α-allyl-β-ketosulfones. This process employs fac-Ir(ppy)3 as the photoredox catalyst and α-carbonyl alkyl bromide as the oxidizing agent. Via this approach, the substrates experience intermolecular addition of α-carbonyl alkyl radicals to the alkene bonds, initiating a sequence of C-C bond formations that culminate in the production of organosulfone derivatives. Notably, this technique features gentle reaction conditions and an exceptional compatibility with a wide array of functional groups, making it a versatile and valuable addition to the field of organic synthesis. [ABSTRACT FROM AUTHOR]

Fixing the greenhouse gas CO2 through epoxide helps to mitigate worldwide ecological troubles. The applications of metal‐free and solvent‐free catalysts remain a challenge for CO2 catalytic conversion. In this work, an array of quaternary ammonium salts derived from polyethyleneimine with hydroxyl groups ([PEI‐GDMAB‐Cn]Br) were constructed by the reaction of branched PEI with a molecular weight of 10000 and glycidyl alkyl dimethylammonium bromide. A range of experiments were designed to demonstrate that [PEI‐GDMAB‐Cn]Br can be considered as a valid metal‐free and solvent‐free homogeneous catalyst for the CO2‐epoxide cycloaddition reaction. Among of [PEI‐GDMAB‐Cn]Br, [PEI‐GDMAB‐C18]Br catalyzed the model reaction of CO2 and epichlorohydrin under optimized reaction conditions (T=80 °C, 1.0 atm CO2, catalyst 1 mol%, ECH 15 mmol, 16 h) and the conversion achieved at 97.5 %. Moreover, the catalyst exhibited stable reusability and broad substrate applicability, which was used in the following cycle succinctly, because of self‐separated properties by temperature control. The [PEI‐GDMAB‐C18]Br catalyzed reaction process was detected as a pseudo‐first‐order reaction after kinetic studies and an Ea was calculated to be 50.65 kJ/mol. A combinatorial catalytic mechanism of hydrogen bonding and bromide ions is suggested to explain the remarkable catalytic performance of this bifunctional catalyst. [ABSTRACT FROM AUTHOR]

Comprehensive Summary An alkyl radical initiated cyclization/tandem reaction of alkyl bromides and alkyl electrophiles by using potassium metabisulphite (K2S2O5) as a connector is developed for the synthesis of various lactam‐substituted alkyl sulfones. Notably, this process does not require a metal catalyst or metal powder reductant, highlighting its environmentally friendly features. The reaction demonstrates outstanding substrate adaptability and a high tolerance towards diverse functional groups. Furthermore, the biologically active molecules and commercially available drugs with a late‐stage modification are also highly compatible with this transformation. Mechanistic studies revealed that the reaction proceeds through a single‐step process involving intramolecular radical cyclization, "SO2" insertion, and external alkyl incorporation. [ABSTRACT FROM AUTHOR]

A selective C(sp3)−S bond cleavage of thioethers mediated by NBS is developed. Various alkyl bromides have been obtained in good yields using N‐aryl‐3‐(methylthio)propanamides and arylmethylene alkylthioethers. Mechanistic studies suggest that the formation of 3‐bromo‐N‐arylpropanamides may involve sulfoxide intermediates, while the arylmethylene bromides are formed through direct bromination process mediated by NBS. The significance of this strategy lies in its pioneering use of NBS for C−S bond cleavage and subsequent bromination reaction. [ABSTRACT FROM AUTHOR]

Herein, a sensitive and selective gas chromatography-electron capture detector (GC-ECD) method was developed and validated for the quantification of trace levels of five bromo-containing genotoxic impurities in Febuxostat active pharmaceutical ingredient (API) after headspace sampling (HS). Multivariate experimental designs for the optimization of static headspace parameters were conducted in two stages using fractional factorial design (FFD) and central composite design (CCD). The optimum headspace conditions were 5 min of extraction time and a 120 °C extraction temperature. Baseline separation on the analytes against halogenated solvents was carried out using an Agilent DB-624 (30 m × 0.32 mm I.D., 1.8 μm film thickness) stationary phase under isothermal conditions. The method was validated according to ICH guidelines in terms of specificity, linearity, the limits of detection and quantification, precision and accuracy. The linearity was assessed in the range of 5–150% with respect to the specification limit. The achieved LOD and LOQ values ranged between 0.003 and 0.009 and 0.01 and 0.03 μg mL−1, respectively. The accuracy of the method (expressed as relative recovery) was in the range of 81.5–118.2%, while the precision (repeatability, inter-day) was less than 9.9% in all cases. The validated analytical protocol has been successfully applied to the determination of the impurities in various Febuxostat API batch samples. [ABSTRACT FROM AUTHOR]

In this study, we synthesized azepinodiazepine derivatives in high yields using multicomponent reactions of isatins, activated acetylenic compounds, alkyl bromides, methyl aziridine and ammonium acetate in the presence of Fe3O4/ZnO@MWCNT as a high-performance catalyst and teiethyl amine in water at room temperature. The Fe3O4/ZnO@MWCNT synthesizes using Petasites hybridus rhizome water extract as a green media and moderate base. Also, the catalytic activity of the green synthesized Fe3O4/ZnO@MWCNT MNCs was evaluated in the reduction of organic pollutants such as 4-nitrophenol (4-NP) in water at mild conditions. The results indicated that the biosynthesized NCs have very high and effective catalytic activity for organic pollutants within a few seconds. Investigation of the antioxidant ability of synthesized compounds using radical trapping of diphenyl-picrylhydrazine (DPPH) and ferric reduction power experiment is another purpose of this research. Also, the antimicrobial activity of some synthesized compounds was proved by employing the disk diffusion test on Gram-positive and Gram-negative bacteria. Also, to better understanding reaction mechanism density functional theory (DFT) based quantum chemical methods have been applied. This procedure has some benefits such as short reaction time, products with excellent yields, simple catalyst and product separation. Green chemistry is the use of a set of principles to reduce or eliminate the use or generation of unsafe materials in the design, fabrication and applications of chemical products. Among solvents, water is a green solvents and very suitable for performing organic reaction. The present procedure avoids the use of toxic solvent. Some representatives of this class of azaheterocycles are known as antiviral agents, glycosidase inhibitors, anticancer agents or antidiabetics. Therefore, in view of their medicinal relevance, an increasing number of synthetic methods have been described in recent years for the construction of highly substituted azepine derivatives. [ABSTRACT FROM AUTHOR]

A reductive cross-coupling strategy for the synthesis of sulfone-containing oxindoles via palladium-catalyzed domino cyclization/alkylsulfonylation reaction of N-substituted arylacrylamides with unactivated alkyl bromides and Na2S2O5 is presented. Moreover, using amines instead of alkyl bromides, a palladium-catalyzed domino cyclization/aminosulfonylation was also established. [ABSTRACT FROM AUTHOR]

Silylzinc reagents are desirable for the synthesis of organosilanes due to their compatibility with functional groups; however, the use of pyrophoric silyllithium and dissolved lithium salts in their production hinders their development. Our solid Me3SiZnI circumvents these limitations, and herein, we demonstrate its significance in the synthesis of aryl and alkyl trimethylsilanes via cross‐coupling of aryl and alkyl bromides. The milder reaction condition tolerates functional groups such as MOM, Boc, Bpin, and aldehydes. [ABSTRACT FROM AUTHOR]

gem‐Dibromoalkanes are important synthetic building block in organic chemistry, but their preparation is still troublesome. Herein, we have developed a simple and practical protocol for the synthesis of gem‐dibromoalkanes from aldehydes using tetrabutylammonium tribromide and triphenyl phosphite. A variety of alkyl and aromatic aldehydes can be transformed into the corresponding products within 10 minutes. This protocol is also applicable to alcohols, and the configuration of chiral alcohol is inverted during the process with excellent enantiopurity. [ABSTRACT FROM AUTHOR]

Sulfonyl groups are widely observed in biologically relevant molecules and consequently, SO2 capture is an increasingly attractive method to prepare these sulfonyl‐containing compounds given the range of SO2‐surrogates now available as alternatives to using the neat gas. This, along with the advent of photoredox catalysis, has enabled mild radical capture of SO2 to emerge as an effective route to sulfonyl compounds. Here we report a photoredox‐catalyzed cross‐electrophile sulfonylation of aryl and alkyl bromides making use of a previously under‐used amine‐SO2 surrogate; bis(piperidine) sulfur dioxide (PIPSO). A broad selection of alkyl and aryl bromides were photocatalytically converted to their corresponding sulfinates and then trapped with various electrophiles in a one‐pot multistep procedure to prepare sulfones and sulfonamides. [ABSTRACT FROM AUTHOR]

A cobalt‐catalyzed 1,2‐regioselective dicarbofunctionalization of silylated 1,3‐dienes with functionalized solid organozinc pivalates and alkyl bromides is disclosed, thus affording the alkylarylated and dialkylated silanes in a regioselective manifold. Herein, regioselectivity is steered by steric hindrance of the bulky silyl groups, which could prohibit the formation of the flexible π‐allylcobalt intermediate. Furthermore, derivatizations of the resulting products and modifications of bioactive molecules demonstrate the synthetical utility of our method. [ABSTRACT FROM AUTHOR]

The present work represents the propyl modification and characterization of Moringa gum for sustained drug delivery applications. The propylation of Moringa gum was performed using n-propyl bromide by alkyl etherification process. The propylated Moringa gum was further evaluated as a diclofenac sodium-loaded matrix tablet and composite beads for sustained drug delivery. The modification of Moringa gum was confirmed by infrared spectroscopy. The degree of propyl substitution was determined to be 0.407. The characterization studies revealed the increase in the degree of crystallinity, thermal stability, surface roughness, and the decrease in viscosity on propyl modification. The native and modified gum had a molecular weight of 1.02 × 104 and 4.84 × 104 KDa, respectively. The diclofenac-loaded matrix tablets of Moringa gum disintegrated in simulated gastric fluid, while tablets of propyl Moringa gum provided sustained release of diclofenac by super case 2 transport following Higuchi release kinetics. The ionically gelled beads of propyl Moringa gum were able to control the burst release of diclofenac in simulated gastric fluid releasing 84% of the drug in 24 h following Higuchi kinetics. It can be concluded that the propyl-modified Moringa gum can be used as a pharmaceutical excipient for sustained drug delivery applications. [ABSTRACT FROM AUTHOR]

The synthesis of bis-quaternary ammonium compounds based on a polyhydric alcohol, 2,3-bis(hydroxymethyl)butane-1,4-diol, and pyridine was accomplished. The bacteriostatic and bactericidal activity of the products against ESKAPE pathogens and Candida albicans yeast-like fungus both in planktonic and biofilm forms was studied. The activity of the bis-pyridinium salts was compared with the activities of known antiseptic agents, octenidine dihydrochloride and cetylpyridinium chloride. It was found that the compound containing ten carbon atoms in the alkyl group is effective against various strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and C. albicans. [ABSTRACT FROM AUTHOR]

The precise control of the regioselectivity in the transition metal‐catalyzed migratory hydrofunctionalization of alkenes remains a big challenge. With a transient ketimine directing group, the nickel‐catalyzed migratory β‐selective hydroarylation and hydroalkenylation of alkenyl ketones has been realized with aryl boronic acids using alkyl halide as the mild hydride source for the first time. The key to this success is the use of a diphosphine ligand, which is capable of the generation of a Ni(II)‐H species in the presence of alkyl bromide, and enabling the efficient migratory insertion of alkene into Ni(II)‐H species and the sequent rapid chain walking process. The present approach diminishes organosilanes reductant, tolerates a wide array of complex functionalities with excellent regioselective control. Moreover, this catalytic system could also be applied to the migratory hydroarylation of alkenyl azahetereoarenes, thus providing a general approach for the preparation of 1,2‐aryl heteroaryl motifs with wide potential applications in pharmaceutical discovery. [ABSTRACT FROM AUTHOR]

Reactions of unactivated alkyl chlorides under mild and sustainable conditions are rare compared to those of alkyl bromides or iodides. As a result, synthetic methods capable of modifying the vast chemical space of chloroalkane reagents, wastes, and materials are limited. We report the cobalt‐catalyzed reductive addition of unactivated alkyl chlorides to conjugated alkenes. Co‐catalyzed activation of alkyl chlorides is performed under electroreductive conditions, and the resulting reactions constitute formal alkyl‐alkyl bond formation. In addition to developing an operationally simple methodology, detailed mechanistic studies provide insights into the elementary steps of a proposed catalytic cycle. In particular, we propose a switch in the mechanism of C−Cl bond activation from nucleophilic substitution to halogen atom abstraction, which is critical for efficiently generating alkyl radicals. These mechanistic insights were leveraged in designing ligands that enable couplings of primary, secondary, and tertiary alkyl chlorides. [ABSTRACT FROM AUTHOR]

In this study, we synthesized azepinooxazepine derivatives in high yields using multicomponent reactions of aniline, diethyl carbonate, alkyl bromides, activated acetylenic compounds, methyl aziridine and Fe3O4/ZnO@MWCNT as a high performance catalyst and teiethyl amine in water at room temperature. The catalytic activity of the green synthesized Fe3O4/ZnO@MWCNT MNCs was evaluated in the reduction of organic pollutants such as 4-nitrophenol (4-NP) in water at mild conditions. The results indicated that the biosynthesized NCs have very high and effective catalytic activity for organic pollutants within few seconds. Investigation of antioxidant ability of synthesized compounds using radical trapping of DPPH and ferric reduction power experiment is another purpose in this research. Also, the antimicrobial activity of some synthesized compounds proved by employing the disk diffusion test on Gram-positive and Gram-negative bacteria. Also, density functional theory (DFT) based quantum chemical methods have been applied for better understanding reaction mechanism. Green chemistry is the use of a set of principles to reduce or eliminate the use or generation of unsafe materials in the design, fabrication and applications of chemical products. Among solvents, water is a green solvents and very suitable for performing organic reaction. The present procedure avoids the use of toxic solvent. Some representatives of this class of azaheterocycles are known as antiviral agents, glycosidase inhibitors, anticancer agents or antidiabetics. Therefore, in view of their medicinal relevance, an increasing number of synthetic methods have been described in recent years for the construction of highly substituted azepine derivatives. [ABSTRACT FROM AUTHOR]

Reactions of unactivated alkyl chlorides under mild and sustainable conditions are rare compared to those of alkyl bromides or iodides. As a result, synthetic methods capable of modifying the vast chemical space of chloroalkane reagents, wastes, and materials are limited. We report the cobalt‐catalyzed reductive addition of unactivated alkyl chlorides to conjugated alkenes. Co‐catalyzed activation of alkyl chlorides is performed under electroreductive conditions, and the resulting reactions constitute formal alkyl‐alkyl bond formation. In addition to developing an operationally simple methodology, detailed mechanistic studies provide insights into the elementary steps of a proposed catalytic cycle. In particular, we propose a switch in the mechanism of C−Cl bond activation from nucleophilic substitution to halogen atom abstraction, which is critical for efficiently generating alkyl radicals. These mechanistic insights were leveraged in designing ligands that enable couplings of primary, secondary, and tertiary alkyl chlorides. [ABSTRACT FROM AUTHOR]

The precise control of the regioselectivity in the transition metal‐catalyzed migratory hydrofunctionalization of alkenes remains a big challenge. With a transient ketimine directing group, the nickel‐catalyzed migratory β‐selective hydroarylation and hydroalkenylation of alkenyl ketones has been realized with aryl boronic acids using alkyl halide as the mild hydride source for the first time. The key to this success is the use of a diphosphine ligand, which is capable of the generation of a Ni(II)‐H species in the presence of alkyl bromide, and enabling the efficient migratory insertion of alkene into Ni(II)‐H species and the sequent rapid chain walking process. The present approach diminishes organosilanes reductant, tolerates a wide array of complex functionalities with excellent regioselective control. Moreover, this catalytic system could also be applied to the migratory hydroarylation of alkenyl azahetereoarenes, thus providing a general approach for the preparation of 1,2‐aryl heteroaryl motifs with wide potential applications in pharmaceutical discovery. [ABSTRACT FROM AUTHOR]

Electrochemical approaches to form C(sp2)−C(sp3) bonds have focused on coupling C(sp3) electrophiles that form stabilized carbon‐centered radicals upon reduction or oxidation. Whereas alkyl bromides are desirable C(sp3) coupling partners owing to their availability and cost‐effectiveness, their tendency to undergo radical‐radical homocoupling makes them challenging substrates for electroreductive cross‐coupling. Herein, we disclose a metal‐free regioselective cross‐coupling of 1,4‐dicyanobenzene, a useful precursor to aromatic nitriles, and alkyl bromides. Alkyl bromide reduction is mediated directly by 1,4‐dicyanobenzene radical anions, leading to negligible homocoupling and high cross‐selectivity to form 1,4‐alkyl cyanobenzenes. The cross‐coupling scheme is compatible with oxidatively sensitive and acidic functional groups such as amines and alcohols, which have proven difficult to incorporate in alternative electrochemical approaches using carboxylic acids as C(sp3) precursors. [ABSTRACT FROM AUTHOR]

Electrochemical approaches to form C(sp2)−C(sp3) bonds have focused on coupling C(sp3) electrophiles that form stabilized carbon‐centered radicals upon reduction or oxidation. Whereas alkyl bromides are desirable C(sp3) coupling partners owing to their availability and cost‐effectiveness, their tendency to undergo radical‐radical homocoupling makes them challenging substrates for electroreductive cross‐coupling. Herein, we disclose a metal‐free regioselective cross‐coupling of 1,4‐dicyanobenzene, a useful precursor to aromatic nitriles, and alkyl bromides. Alkyl bromide reduction is mediated directly by 1,4‐dicyanobenzene radical anions, leading to negligible homocoupling and high cross‐selectivity to form 1,4‐alkyl cyanobenzenes. The cross‐coupling scheme is compatible with oxidatively sensitive and acidic functional groups such as amines and alcohols, which have proven difficult to incorporate in alternative electrochemical approaches using carboxylic acids as C(sp3) precursors. [ABSTRACT FROM AUTHOR]

A method is developed for preparing 18O‐labeled esters through a Ni‐catalyzed three‐component reaction of amides, alkyl halides, and 18O‐labeled water. This method demonstrated excellent selectivity and compatibility with various amides and alkyl halides, allowing the synthesis of diverse isotopically labelled esters. Ni‐catalyzed reaction of alkyl bromides, carboxylates that generated from amides, and water in the presence of a base formed the desired esters. [ABSTRACT FROM AUTHOR]

Recent publications on direct reactions of elemental phosphorus with organic halides (alkyl bromides, aryl (and hetaryl) halides, and aryl (and hetaryl) methyl halides) in the presence of superbasic and micellar catalysts are considered. The development of effective, technologically and environmentally acceptable methods for obtaining alkyl(and benzyl)-H-phosphinic and alkylphosphonic acids, triaryl(and hetaryl)phosphines and hetarylmethylphosphine oxides based on the above reactions is analyzed. [ABSTRACT FROM AUTHOR]

A series of Gemini surfactants (GSs) were prepared by reacting alkyl bromides with N,N,N′,N′‐tetramethyl ethylenediamine. Various alkyl bromides used in for the preparation of GSs are 1,3‐dibromo ethane, 1,3‐dibromoethane, 1‐Bromohexane, 1‐Bromooctane, 1‐Bromooctadecane and 1‐Bromooctadodecane. Different solvents and temperatures were investigated for the formation of gels of prepared GSs. Among all, 1‐Bromooctane, 1‐Bromooctadecane‐derived GSs formed organogels. Thus, synthesized long‐chain organogels have been used to stabilize Pd NPs. The Pd NPs formation initially confirmed through Ultraviolet‐visible, Scanning Electron Microscopy, and Atomic Force Micrograph studies. Later Fourier Tansform Infra Red, Thermo Gravimetric Analysis, and Zeta potential studies were also carried out to understand their properties extensively. The Pd NPs stabilized by GSs have been identified as a potential catalyst in the reductive N‐acetylation of nitroaromatics at room temperature. The N‐acetylated products were obtained in good yields in an aqueous medium. In addition, the potentiality of our catalyst has been also evaluated in the reduction of nitroaromatics in an aqueous medium, which is a green protocol. Further, the semi‐empirical geometry optimizations of active GS gel confirmed the dihedral angle of 59° in between the two octyl moieties calculated from computational studies. The rheological properties such as amplitude sweeping, viscosity shear profile of the gel have also been studied. [ABSTRACT FROM AUTHOR]

A method has been developed for the selective C(2)H alkylation of (benz)oxazoles with tertiary alkyl chlorides and alkyl bromides under visible light-induced (460 nm) catalysis with the Pd(PPh3)4/[Bu4N]I system in N,N-dimethylacetamide. The tetraalkylammonium salt has a significant promoting effect on the reaction, which seems to be based on the stabilization of nanosized palladium species in the catalytic system. [ABSTRACT FROM AUTHOR]

In this study, glycerol derivatives, namely solketal ethers (SEs), were synthesized by Williamson etherification of solketal with alkyl bromide, catalyzed by tetrabutylammonium iodide (TBAI) and basic aqueous potassium hydroxide (KOH). Under optimized reaction conditions: solketal/alkyl bromide (1 : 1), TBAI (5 mol %), KOH solution (2 equiv), 100 °C, 24 hours, SE were obtained between 21 and 94 %. The influence of the incorporation of SE in palm‐based biodiesel was evaluated using kinematic viscosity, cloud point (CP), and pour point (PP). The addition of 5 wt % of 4‐((butoxy)methyl)‐2,2‐dimethyl‐1,3‐dioxolane reduced PP and CP by 5 and 3 °C, respectively, with viscosity values well within the range of ASTM D6751‐12 standard specifications. [ABSTRACT FROM AUTHOR]

Anion exchange membranes fabricated through a one-step Menshutkin reaction with down-selected multifunctional alkyl halides and multifunctional tertiary amines within an ion-solvating matrix, poly(ethylene-co-vinyl alcohol), yielded alkaline-stable ammonium network polymers. Due to the vast simplicity in fabrication due to the quaternization/Menshutkin reaction between tertiary amine and alkyl bromides, which does not evolve any by-products that require purification, alkaline-stable membranes were fabricated in one step through facile mixing and curing of alkaline-stable ammonium network forming monomers. Prepared membranes showed controllable ion exchange capacity (IEC), conductivity, and mechanical strength by controlling of poly(ethylene-co-vinyl alcohol) amount which is an ion-solvating polymer. The selection of ammonium network chemical structure allowed for flawless retention of IEC and conductivity under conditions of 70°C, 1M KOH of over 300 h. Anion exchange membrane electrolysis membrane electrode assembly tests with optimized membranes showed a greater performance (1.78 A/cm2 at 2.0 V) and more enhanced water electrolyzer durability than that of commercial anion exchange membrane. [ABSTRACT FROM AUTHOR]

Aliphatic trifluoromethyl ketones are a type of unique fluorine‐containing subunit which play a significant role in altering the physical and biological properties of molecules. Catalytic methods to provide direct access to aliphatic trifluoromethyl ketones are highly desirable yet remain underdeveloped, partially owing to the high reactivity and instability of trifluoroacetyl radical. Herein, we report a photocatalytic synthesis of trifluoromethyl ketones from alkyl bromides with trifluoroacetic anhydride. The reaction features dual visible‐light and halogen‐atom‐transfer catalysis, followed by an enabling radical‐radical cross‐coupling of an alkyl radical with a stabilized trifluoromethyl radical. The reaction provides straightforward access to aliphatic trifluoromethyl ketones from readily available and cost‐effective alkyl halides and trifluoroacetic anhydride (TFAA). [ABSTRACT FROM AUTHOR]

Aliphatic trifluoromethyl ketones are a type of unique fluorine‐containing subunit which play a significant role in altering the physical and biological properties of molecules. Catalytic methods to provide direct access to aliphatic trifluoromethyl ketones are highly desirable yet remain underdeveloped, partially owing to the high reactivity and instability of trifluoroacetyl radical. Herein, we report a photocatalytic synthesis of trifluoromethyl ketones from alkyl bromides with trifluoroacetic anhydride. The reaction features dual visible‐light and halogen‐atom‐transfer catalysis, followed by an enabling radical‐radical cross‐coupling of an alkyl radical with a stabilized trifluoromethyl radical. The reaction provides straightforward access to aliphatic trifluoromethyl ketones from readily available and cost‐effective alkyl halides and trifluoroacetic anhydride (TFAA). [ABSTRACT FROM AUTHOR]

In this study, new indenopyrimidin-1,2,4-triazol derivatives were synthesized in high yields using multicomponent reactions of ninhydrins, guanidine, alkyl bromides, aldehydes and hydrazonoyl chloride in the presence of Fe3O4/CuO/ZnO@Multi-Walled Carbon Nanotube Magnetic Nanocomposites (Fe3O4/CuO/ZnO@MWCNT MNCs) as a high performance catalyst in water at room temperature. The Fe3O4/CuO/ZnO@MWCNT MNCs was prepared using Petasites hybridus rhizome water extract as a green media and moderate base. This procedure had some benefits such as short reaction time, products with excellent yields, simple catalyst and products separation. The Fe3O4/CuO/ZnO@MWCNT MNCs was showed a good improvement in the yield of the product and displayed significant reusable activity as well. Investigation of antioxidant ability of synthesized compounds using radical trapping of diphenyl-picrylhydrazine (DPPH) and ferric reduction power experiment were another purpose in this research. Green chemistry is the use of a set of principles to reduce or eliminate the use or generation of unsafe materials in the design, fabrication and applications of chemical products. Among solvents, water is a green solvents and very suitable for performing organic reaction. The present procedure avoids the use of toxic solvent. Substituted 1,2,4-triazoles and their derivatives are key skeleton of many biologically active molecules and important organic compounds that exhibit wide applications in pesticides, medicines, functional materials and organocatalysts. [ABSTRACT FROM AUTHOR]

Activated alkyl halides have been extensively explored to generate alkyl radicals with Ru‐ and Ir‐ photocatalysts for 1,2‐difunctionalization of alkenes, but unactivated alkyl bromides remain challenging substrates due to their strong reduction potential. Here we report a three‐component 1,2‐difunctionalization reaction of alkenes, unactivated alkyl bromides and nucleophiles (e.g. amines and indoles) using a trinuclear gold catalyst [Au3(tppm)2](OTf)3. It can achieve the 1,2‐aminoalkylation and 1,2‐alkylarylation readily. This protocol has a broad reaction scope and excellent functional group compatibility (>100 examples with up to 96 % yield). It also affords a robust formal [2+2+1] cyclization strategy for the concise construction of pyrrolidine skeletons under mild reaction conditions. Mechanistic studies support an inner‐sphere single electron transfer pathway for the successful cleavage of inert C−Br bonds. [ABSTRACT FROM AUTHOR]

Activated alkyl halides have been extensively explored to generate alkyl radicals with Ru‐ and Ir‐ photocatalysts for 1,2‐difunctionalization of alkenes, but unactivated alkyl bromides remain challenging substrates due to their strong reduction potential. Here we report a three‐component 1,2‐difunctionalization reaction of alkenes, unactivated alkyl bromides and nucleophiles (e.g. amines and indoles) using a trinuclear gold catalyst [Au3(tppm)2](OTf)3. It can achieve the 1,2‐aminoalkylation and 1,2‐alkylarylation readily. This protocol has a broad reaction scope and excellent functional group compatibility (>100 examples with up to 96 % yield). It also affords a robust formal [2+2+1] cyclization strategy for the concise construction of pyrrolidine skeletons under mild reaction conditions. Mechanistic studies support an inner‐sphere single electron transfer pathway for the successful cleavage of inert C−Br bonds. [ABSTRACT FROM AUTHOR]

The difunctionalization of unsaturated bonds plays a vital role in the enrichment of molecular complexity. While various catalytic methods for alkene and alkyne difunctionalization have been developed in recent years, hetero‐functionalization the introduction of two different atoms has been less explored. This is mainly due to the challenges associated with achieving high chemo‐, regio‐, and stereoselectivity, especially when adding two similar atoms from the same group across unsaturated bonds. In this study, we describe a nickel‐catalyzed, three‐component reductive protocol for group 14 element hetero‐difunctionalization of 1,3‐enynes using electrochemistry. This new method is mild, selective, and general, allowing for the silyl‐, germanyl‐, and stannyl‐alkylation of enynes. Various chlorosilanes as well as chlorogermans, and chlorostannanes can be successfully used in combination with aryl/alkyl‐substituted 1,3‐enynes and primary, secondary, and tertiary alkyl bromides in the electroreductive coupling. [ABSTRACT FROM AUTHOR]

The difunctionalization of unsaturated bonds plays a vital role in the enrichment of molecular complexity. While various catalytic methods for alkene and alkyne difunctionalization have been developed in recent years, hetero‐functionalization the introduction of two different atoms has been less explored. This is mainly due to the challenges associated with achieving high chemo‐, regio‐, and stereoselectivity, especially when adding two similar atoms from the same group across unsaturated bonds. In this study, we describe a nickel‐catalyzed, three‐component reductive protocol for group 14 element hetero‐difunctionalization of 1,3‐enynes using electrochemistry. This new method is mild, selective, and general, allowing for the silyl‐, germanyl‐, and stannyl‐alkylation of enynes. Various chlorosilanes as well as chlorogermans, and chlorostannanes can be successfully used in combination with aryl/alkyl‐substituted 1,3‐enynes and primary, secondary, and tertiary alkyl bromides in the electroreductive coupling. [ABSTRACT FROM AUTHOR]

In this research we have synthesized new derivatives of dihydrobenzopyrazoloazepine in high yields using multicomponent reaction of anilines, oxalylchloride, alkyl bromides, activated acetylenic compounds, and hydrazine in the presence of Ag/Fe3O4/CdO@MWCNTs MNCs as a high-performance catalyst in ionic liquid at room temperature. The Ag/Fe3O4/CdO@MWCNTs MNCs were synthesized using ionic liquid 1-Octhyl-3-methyl imidazolium bromide ([OMIM]Br) as a stabilizer and soft template. Because of having NH group in the synthesized compounds, the antioxidant property of some synthesized dihydrobenzopyrazoloazepine was investigated by diphenyl-picrylhydrazine (DPPH) radical trapping and power of ferric reduction experiment. Also, the catalytic activity of the green synthesized Ag/Fe3O4/CdO@MWCNTs MNCs was evaluated in the reduction of organic pollutants, such as 4-nitrophenol (4-NP) in water under mild conditions. The results indicated that the biosynthesized NCs have very high and effective catalytic activity for removing organic pollutants within a few seconds. A short time of reaction, high yields of product and easy separation of catalyst and products are some advantages of this procedure. Ionic liquids (ILs) are one of the important examples of green solvents with the capacity to solvate an array of inorganic and organic substrates and vanishingly small vapor pressures. 'ILs are promising substitutes for volatile organic solvents (VOCs).' The present procedure avoids the use of toxic solvents. Benzazepines, which have a seven-membered aza-heterocyclic fused aromatic ring, are of interest because of their biological activity and use as building blocks for natural product synthesis and drug discovery. [ABSTRACT FROM AUTHOR]

The atom transfer radical cyclisation of unactivated alkyl bromides was realized by using a catalytic system of CuBr and Me6-TREN. This protocol is applicable to the preparation of five-membered rings from unsaturated primary and secondary bromides. [ABSTRACT FROM AUTHOR]

Effective access to azolium salts with varying stereoelectronic properties has always fascinated the organometallic chemists. Herein, we described a Ru(II)‐catalyzed one‐step access to diverse meta‐alkylated N‐aryl (benz)imidazolium salts (>40 examples) via σ‐bond activation strategy starting from the readily available azolium salts using alkyl bromide. Notably, the present method is compatible with a wide range of azolium salts and secondary/tertiary alkyl bromides, including the biologically relevant motifs. Various control experiments along with the DFT calculation established the reaction pathway of orthometalated Ru(II)‐NHC complex (6) formation followed by the generation of a Ru(III)‐intermediate, which controls the observed meta‐selectivity, via single electron transfer. Crucially, detailed insight of the reaction mechanism helped to comprehend why some substrates are challenging for this methodology. [ABSTRACT FROM AUTHOR]

Control over polymer architecture and composition is essential for disclosing structure‐property relationships and developing high‐performance materials. Herein, a new method is successfully developed to synthesize bottlebrush polymer (BP) with controllable graft density and side chain composition by "grafting‐from" strategy using in situ halogen exchange and reversible chain transfer catalyzed polymerization (RTCP). The main chain of the BP is first synthesized by the polymerization of methacrylates containing alkyl bromide as a side group. Then, the alkyl bromine is quantitatively converted to alkyl iodide with sodium iodide (NaI) via in situ halogen exchange to efficiently initiate the RTCP of methacrylates. By adjusting the input amount of NaI and monomers in sequence, BP named PBPEMA‐g‐PMMA/PBzMA/PPEGMEMA which contains three different kinds of polymer side chains including hydrophilic PPEGMEMA, hydrophobic PMMA, and PBzMA is synthesized with narrow molecular weight distribution (Mw/Mn ≤ 1.36). The grafting density and the chain length of each polymer side chain are well controlled by the addition of NaI in batches and following RTCP. Moreover, the obtained BP self‐assembled into spherical vesicles in aqueous with hydrophilic coronal structure, core region, and the hydrophobic wall between the former two, which enables to wrap hydrophobic pyrene and hydrophilic Rhodamine 6G separately or simultaneously. [ABSTRACT FROM AUTHOR]

An attractive approach to selective functionalization of remote C−H bonds is a metal/hydride shift/cross‐coupling reaction sequence. Complimentary to the heavily exploited 1,2‐nickel/hydride shift along an sp3 chain, a chain‐walking process, the 1,4‐nickel/hydride shift along an sp2 chain is more complex. Here we report an unprecedented aryl‐to‐vinyl 1,4‐nickel/hydride shift reaction, in which the migratory alkenylnickel species generated in situ is selectively trapped by one of various coupling partners, such as isocyanates, alkyl bromides, aryl chlorides or alkynyl bromides, allowing regio‐ and stereoselective access to trisubstituted alkenes. In contrast to the well‐reported ipso‐aryl coupling reactions, this strategy provides remote alkenyl C−H functionalized products with good yield and with excellent chemo‐, regio‐ and E/Z‐selectivity. [ABSTRACT FROM AUTHOR]

An attractive approach to selective functionalization of remote C−H bonds is a metal/hydride shift/cross‐coupling reaction sequence. Complimentary to the heavily exploited 1,2‐nickel/hydride shift along an sp3 chain, a chain‐walking process, the 1,4‐nickel/hydride shift along an sp2 chain is more complex. Here we report an unprecedented aryl‐to‐vinyl 1,4‐nickel/hydride shift reaction, in which the migratory alkenylnickel species generated in situ is selectively trapped by one of various coupling partners, such as isocyanates, alkyl bromides, aryl chlorides or alkynyl bromides, allowing regio‐ and stereoselective access to trisubstituted alkenes. In contrast to the well‐reported ipso‐aryl coupling reactions, this strategy provides remote alkenyl C−H functionalized products with good yield and with excellent chemo‐, regio‐ and E/Z‐selectivity. [ABSTRACT FROM AUTHOR]

Herein, we report a direct method to prepare alkylzinc compounds from functionalized alkyl bromides using cobalt catalysis under mild conditions. This procedure only requires a simple catalytic system composed of CoBr2 and bipyridine as ligand in a mixture of acetonitrile/pyridine. This reaction is stable under air and moisture conditions opening the way to an accessible procedure. A wide range of functional groups such as esters, cyano and halogens on primary and secondary alkyl bromides was well tolerated and gave high yields of the corresponding alkylzinc compounds. Additionally, we managed to form alkylzinc reagents bearing sensitive functional groups such as ketones and aldehydes with good yields. The direct application of these alkylzinc derivatives in palladium‐catalyzed Negishi cross‐coupling with various functionalized aryl bromides proved the efficiency and robustness of this methodology. [ABSTRACT FROM AUTHOR]

Dinuclear-gold-catalyzed radical difunctionalization of alkyl bromides with 1,7-enynes has been established via dehalogenation and 1,5-HAT processes. This protocol was used to construct, in a facile and efficient manner, a wide range of cyclopenta[c]quinolines bearing two quaternary carbon centers with good yields (28 examples, up to 84% yield). The good functional group compatibility and gram-scale preparation ability of the reaction proved its synthetic robustness. [ABSTRACT FROM AUTHOR]

Despite several methodologies established for C(sp2)−I selective C(sp2)−C(sp3) bond formations, achieving arene‐flanked quaternary carbons by cross‐coupling of tertiary alkyl precursors with bromo(iodo)arenes in a C(sp2)−I selective manner is rare. Here we report a general Ni‐catalyzed C(sp2)−I selective cross‐electrophile coupling (XEC) reaction, in which, beyond 3° alkyl bromides (for constructing arene‐flanked quaternary carbons), 2° and 1° alkyl bromides are also demonstrated to be viable coupling partners. Moreover, this mild XEC displays excellent C(sp2)−I selectivity and functional group compatibility. The practicality of this XEC is demonstrated in simplifying the routes to several medicinally relevant and synthetically challenging compounds. Extensive experiments show that the terpyridine‐ligated NiI halide can exclusively activate alkyl bromides, forming a NiI−alkyl complex through a Zn reduction. Attendant density functional theory (DFT) calculations reveal two different pathways for the oxidative addition of the NiI−alkyl complex to the C(sp2)−I bond of bromo(iodo)arenes, explaining both the high C(sp2)−I selectivity and generality of our XEC. [ABSTRACT FROM AUTHOR]

Despite several methodologies established for C(sp2)−I selective C(sp2)−C(sp3) bond formations, achieving arene‐flanked quaternary carbons by cross‐coupling of tertiary alkyl precursors with bromo(iodo)arenes in a C(sp2)−I selective manner is rare. Here we report a general Ni‐catalyzed C(sp2)−I selective cross‐electrophile coupling (XEC) reaction, in which, beyond 3° alkyl bromides (for constructing arene‐flanked quaternary carbons), 2° and 1° alkyl bromides are also demonstrated to be viable coupling partners. Moreover, this mild XEC displays excellent C(sp2)−I selectivity and functional group compatibility. The practicality of this XEC is demonstrated in simplifying the routes to several medicinally relevant and synthetically challenging compounds. Extensive experiments show that the terpyridine‐ligated NiI halide can exclusively activate alkyl bromides, forming a NiI−alkyl complex through a Zn reduction. Attendant density functional theory (DFT) calculations reveal two different pathways for the oxidative addition of the NiI−alkyl complex to the C(sp2)−I bond of bromo(iodo)arenes, explaining both the high C(sp2)−I selectivity and generality of our XEC. [ABSTRACT FROM AUTHOR]

Simultaneous electrochemical ring contraction and expansion reactions remain unexplored to date. Herein, the reductive electrosynthesis of heterocycle‐fused fulleroids from fullerotetrahydropyridazines and electrophiles in the presence of a trace amount of oxygen has been achieved with concurrent ring contraction and ring expansion. When trifluoroacetic acid and alkyl bromides are employed as electrophiles, heterocycle‐fused fulleroids with a 1,1,2,6‐configuration are regioselectively formed. In contrast, heterocycle‐fused fulleroids with a 1,1,4,6‐configuration are regioselectively produced as two separable stereoisomers if phthaloyl chloride is used as the electrophile. The reaction proceeds through multiple steps of electroreduction, heterocycle ring‐opening, oxygen oxidation, heterocycle contraction, fullerene cage expansion, and nucleophilic addition. The structures of these fulleroids have been determined by spectroscopic data and single‐crystal X‐ray diffraction analyses. The observed high regioselectivities have been rationalized by theoretical calculations. Representative fulleroids have been applied in organic solar cells as the third component and exhibit good performance. [ABSTRACT FROM AUTHOR]

Simultaneous electrochemical ring contraction and expansion reactions remain unexplored to date. Herein, the reductive electrosynthesis of heterocycle‐fused fulleroids from fullerotetrahydropyridazines and electrophiles in the presence of a trace amount of oxygen has been achieved with concurrent ring contraction and ring expansion. When trifluoroacetic acid and alkyl bromides are employed as electrophiles, heterocycle‐fused fulleroids with a 1,1,2,6‐configuration are regioselectively formed. In contrast, heterocycle‐fused fulleroids with a 1,1,4,6‐configuration are regioselectively produced as two separable stereoisomers if phthaloyl chloride is used as the electrophile. The reaction proceeds through multiple steps of electroreduction, heterocycle ring‐opening, oxygen oxidation, heterocycle contraction, fullerene cage expansion, and nucleophilic addition. The structures of these fulleroids have been determined by spectroscopic data and single‐crystal X‐ray diffraction analyses. The observed high regioselectivities have been rationalized by theoretical calculations. Representative fulleroids have been applied in organic solar cells as the third component and exhibit good performance. [ABSTRACT FROM AUTHOR]

In this study, baker's yeast promoted one-pot synthesize of new 1,2,4-triazolpyrimidooxadiazole derivatives in high yields using multicomponent reactions of isatins, guanidine, alkyl bromides, aldehydes and hydrazonoyl chlorides in the presence of baker's yeast as a high performance catalyst in water at room temperature. Investigation of antioxidant ability of synthesized compounds using radical trapping of diphenyl-picrylhydrazine (DPPH) and ferric reduction power experiment is another purpose in this research. Also, the antimicrobial activity of some synthesized compounds proved by employing the disk diffusion test on Gram-positive and Gram-negative bacteria. This procedure has some benefits such as short reaction time, product with excellent yields and simple, efficient, inexpensive, and environment-friendly catalyst. Green chemistry is the use of a set of principles to reduce or eliminate the use or generation of unsafe materials in the design, fabrication and applications of chemical products. Among solvents, water is a green solvents and very suitable for performing organic reaction. The present procedure avoids the use of toxic solvent. 1,3,4-Oxadiazoles are a known class of compounds, reported to exhibit antibacterial, antifungal, analgesic and anti-inflammatory, anticonvulsant, hypoglycemic, and anticancer activities. [ABSTRACT FROM AUTHOR]