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Showing papers on "Reagent published in 2021"


Journal ArticleDOI
TL;DR: In this paper, the authors report the functionalization of numerous feedstock chemicals via the coupling of unactivated C(sp3)-H bonds with electron-deficient olefins.
Abstract: Utilizing catalytic CuCl2 we report the functionalization of numerous feedstock chemicals via the coupling of unactivated C(sp3)-H bonds with electron-deficient olefins The active cuprate catalyst undergoes Ligand-to-Metal Charge Transfer (LMCT) to enable the generation of a chlorine radical which acts as a powerful hydrogen atom transfer reagent capable of abstracting strong electron-rich C(sp3)-H bonds Of note is that the chlorocuprate catalyst is an exceedingly mild oxidant (05 V vs SCE) and that a proposed protodemetalation mechanism offers a broad scope of electron-deficient olefins, offering high diastereoselectivity in the case of endocyclic alkenes The coupling of chlorine radical generation with Cu reduction through LMCT enables the generation of a highly active HAT reagent in an operationally simple and atom economical protocol

123 citations


Journal ArticleDOI
TL;DR: In this article, an efficient and eco-friendly protocol for synthesizing difluoromethylated oxindoles through a visible-light induced one-pot tandem reaction of N-arylacrylamides, Difluoroacetic acid and PhI(OAc)2 was developed.

87 citations


Journal ArticleDOI
Hao Jia1, Andreas P. Häring1, Florian Berger1, Li Zhang1, Tobias Ritter1 
TL;DR: In this article, the synthesis and application of trifluoromethyl thianthrenium triflate (TT-CF3+OTf-) as a novel reagent was reported.
Abstract: Here we report the synthesis and application of trifluoromethyl thianthrenium triflate (TT-CF3+OTf-) as a novel trifluoromethylating reagent, which is conveniently accessible in a single step from thianthrene and triflic anhydride. We demonstrate the use of TT-CF3+OTf- in electrophilic, radical, and nucleophilic trifluoromethylation reactions.

65 citations


Journal ArticleDOI
TL;DR: Decolorization of industrial dyes (leather and weaving industries) is possible using AOPs and Photo-Fenton is a very active method combination, but ultrasounds increase its activity.

61 citations


Journal ArticleDOI
Yajun Wu1, Yang Xu1, Xudong Zhang1, Yitian Lu1, Guang Chen, Xiaodong Wang1, Binjie Song1 
TL;DR: In this article, the optimal amount of Fenton's reagent for conditioning landfill sludge was found to be Fe2+ 4, H2O2 12, and the water content of LS with different pore sizes.

44 citations


Journal ArticleDOI
TL;DR: In this paper, the first application of 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) as a photocatalyst for the synthesis of spiroγ-lactam derivatives, in which the use of transition metals and a high reaction temperature could be avoided.
Abstract: Photocatalytic strategies for the preparation of 3-phosphoryl/trifluoromethyl/thiocyanato azaspiro[4.5]trienones via a radical-initiated cascade annulation reaction of N-arylpropiolamides with phosphorus reagents, 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni's reagent II) or NH4SCN have been developed under blue LED irradiation at room temperature. The novel synthetic methodologies constitute the first application of 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN) as a photocatalyst for the synthesis of spiro-γ-lactam derivatives, in which the use of transition metals and a high reaction temperature could be avoided. The reactions are operationally simple, easy to scale up, and metal-free with wide reaction scope and good functional group tolerance.

41 citations


Journal ArticleDOI
TL;DR: In this article, a vinyl thianthrenium salt was introduced as an effective vinylating reagent, which can be readily prepared from ethylene gas at atmospheric pressure in one step and is broadly useful in the annulation chemistry of (hetero)cycles, N-vinylation of heterocyclic compounds, and palladium-catalyzed crosscoupling reactions.
Abstract: The use of vinyl electrophiles in synthesis has been hampered by the lack of access to a suitable reagent that is practical and of appropriate reactivity. In this work we introduce a vinyl thianthrenium salt as an effective vinylating reagent. The bench-stable, crystalline reagent can be readily prepared from ethylene gas at atmospheric pressure in one step and is broadly useful in the annulation chemistry of (hetero)cycles, N-vinylation of heterocyclic compounds, and palladium-catalyzed cross-coupling reactions. The structural features of the thianthrene core enable a distinct synthesis and reactivity profile, unprecedented for other vinyl sulfonium derivatives.

39 citations


Journal ArticleDOI
TL;DR: In this paper, chemical precipitation using lime (Ca(Ca(OH)2), caustic soda (NaOH) and soda ash (Na2CO3) for the removal of simultaneous heavy metals (Cu(II) and Zn(II)) from industrial wastewater of the cable industry was carried out in laboratory by jar tests.
Abstract: Chemical precipitation using lime (Ca(OH)2), caustic soda (NaOH) and soda ash (Na2CO3) for the removal of simultaneous heavy metals (Cu(II) and Zn(II)) from industrial wastewater of the cable industry was carried out in laboratory by jar tests For each reagent used, an improvement in copper and zinc removal efficiency was obtained by increasing the precipitating reagent dose (10–400 mg/L) Efficiencies of over 90% can be achieved Chemical precipitation efficiency is related to the pH of the treatment At a high final pH level (8 < pH < 10), the removal efficiency of copper for each precipitating agent is slightly higher than that of zinc and the residual metal contents were in conformity with industrial discharge standards In sludge product, zinc and copper were precipitated as amorphous hydroxides including Zn(OH)2 and Cu(OH)2 Based on XRD analysis, the presence of an amount of other additional phases was noticed for copper SEM images show that sludges produced are not large in size and are compact in structure Corresponding EDX (energy-dispersive X-ray spectroscopy) shows that the amount of copper is higher than the amount of zinc in all recovered sludge Wastewater treatment with soda ash resulted in a lower volume and a large product size of sludge As a result, drying steps can be less expensive This is a significant advantage comparably with the other precipitating agents Soda ash may be considered as cost-effective precipitating agent for Cu(II) and Zn(II) in the industrial wastewater of the cable industry

38 citations


Journal ArticleDOI
TL;DR: In this article, an electrochemical approach that is able to hydrocarboxylate a,bunsaturated alkenes with excellent regioselectivity and the ability to carboxylates hindered substrates to afford a-quaternary center carboxylic acids is presented.
Abstract: The carboxylation of low-value commodity chemicals to provide higher-value carboxylic acids is of significant interest. Recently alternative routes to the traditional hydroformylation processes that used potentially toxic carbon monoxide and a transition metal catalyst have appeared. A significant challenge has been the selectivity observed for olefin carboxylation. Photochemical methods have shown a viable route towards the hydrocarboxylation of a,b-unsaturated alkenes but rely on the use of an excess reducing or amine reagent. Herein we report our investigations of an electrochemical approach that is able to hydrocarboxylate a,bunsaturated alkenes with excellent regioselectivity and the ability to carboxylate hindered substrates to afford a-quaternary center carboxylic acids. The reported process requires no chromatography and the products are purified by simple crystallization from the reaction mixture after work-up.

37 citations


Journal ArticleDOI
TL;DR: Copper oxide (CuO) is used as a reusable solid reagent for hydrogenation of nitro-arenes to aminoarenes as discussed by the authors, which can be regenerated to active CuO by thermal oxidation.
Abstract: Copper oxide (CuO) is used as a reusable solid reagent for hydrogenation of nitroarenes to aminoarenes. The use of CuO resulted in 100 % conversion of 2.9 mmol of nitrobenzene to aniline in 45 s at room temperature using hydrazine hydrate as the reducing agent. During the reaction, CuO is converted to inactive metallic Cu which can be regenerated to active CuO by thermal oxidation. DFT simulations indicated facile formation of oxygen vacancies (EO,vac = −3.8 kJ/mol) on the surface of CuO (111) in reducing environment which is consistent with the XPS analysis. Oxygen vacancies facilitate stronger nitrobenzene binding (−148.5 kJ/mol) and reduced activation barrier (Ea = 36.4 kJ/mol) for N O dissociation. Motivated from this mechanistic insight -NO2 groups in various nitroarenes were selectively hydrogenated to NH2 groups using CuO.

34 citations


Journal ArticleDOI
TL;DR: In this article, the authors reported the application of cavitation for real industrial effluent treatment, which was derived from the cellulosic fiber manufacturing sector, individually or in combination with advanced oxidation processes.

Journal ArticleDOI
TL;DR: In this article, a safe and practical synthesis of a bench-stable and easy-to-handle solution of Pentafluorosulfanyl chloride (SF5 Cl) in n-hexane under gas-reagent-free conditions was described.
Abstract: Pentafluorosulfanyl chloride (SF5 Cl) is the most prevalent reagent for the incorporation of SF5 group into organic compounds. However, the preparation of SF5 Cl often relies on hazardous reagents and specialized apparatus. Herein, we described a safe and practical synthesis of a bench-stable and easy-to-handle solution of SF5 Cl in n-hexane under gas-reagent-free conditions. The synthetic application of SF5 Cl was demonstrated through the unprecedented reaction with diazo compounds. The chemoselective hydro- and chloropentafluorosulfanylations of α-diazo carbonyl compounds were developed in the presence of K3 PO4 or copper catalyst, respectively. These reactions provide a direct and efficient access to various α-pentafluorosulfanyl carbonyl compounds of high value for potential applications.

Journal ArticleDOI
TL;DR: In this article, a bifunctional ultrathin Fe-Nx-C single-atom catalysts (SACs) was successfully prepared and investigated as both cathode and anode material for EER and aromatic chlorination reaction (ACR), respectively.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a triple role of protic ionic liquids with nucleophilic anions: a regenerable solvent, a Bronsted acid inducing diverse transformations via general acid catalysis and a source of a nucleophile.
Abstract: We propose a new concept of the triple role of protic ionic liquids with nucleophilic anions: a) a regenerable solvent, b) a Bronsted acid inducing diverse transformations via general acid catalysis, and c) a source of a nucleophile. The efficiency of this strategy was demonstrated using thiocyanate-based protic ionic liquids for the ring-opening of donor-acceptor cyclopropanes. A wide variety of activated cyclopropanes were found to react with 1-methylimidazolium thiocyanate under mild metal-free conditions via unusual nitrogen attack of the ambident thiocyanate ion on the electrophilic center of the three-membered ring affording pyrrolidine-2-thiones bearing donor and acceptor substituents at the C(5) and C(3) atoms, respectively, in a single time-efficient step. The ability of 1-methylimidazolium thiocyanate to serve as a triplex reagent was exemplarily illustrated by (4+2)-annulation with 1-acyl-2-(2-hydroxyphenyl)cyclopropane, epoxide ring-opening and other organic transformations.

Journal ArticleDOI
TL;DR: This novel, practical reaction leads to the formation of two distinct new bonds (S=O and S−N) in a single step to chemoselectively form valuable, unprotected sulfinamide products.
Abstract: An iron catalyzed reaction for the selective transformation of thiols (-SH) to sulfinamides (-SONH2 ) by a direct transfer of -O and free -NH2 groups has been developed. The reaction operates under mild conditions using a bench stable hydroxylamine derived reagent, exhibits broad functional group tolerance, is scalable and proceeds without the use of any precious metal catalyst or additional oxidant. This novel, practical reaction leads to the formation of two distinct new bonds (S=O and S-N) in a single step to chemoselectively form valuable, unprotected sulfinamide products. Preliminary mechanistic studies implicate the role of the alcoholic solvent as an oxygen atom donor.

Journal ArticleDOI
TL;DR: By not hydrolyzing, oxidizing, or decomposing into other chemical species, SDIBDTPI, BHA, and OHA may be considered environmentally friendly reagents, and it is important to promote the adoption of these collectors in mineral processing.

Journal ArticleDOI
TL;DR: In this paper, an efficient trifluoromethylation reagent, TFSP, was reported, which can be readily prepared from cheap and easily available bulk industrial feedstocks.

Journal ArticleDOI
TL;DR: In this article, the Wolff-Kishner reduction was used to couple various alcohols, aldehydes, and ketones with a broad range of both hard and soft carbon electrophiles in the presence of catalytic amounts of transition metals via the hydrazone derivatives.
Abstract: Construction of new carbon–carbon bonds is the cornerstone of organic chemistry. Organometallic reagents are amongst the most robust and versatile nucleophiles for this purpose. Polarization of the metal–carbon bonds in these reagents facilitates their reactions with a vast array of electrophiles to achieve chemical diversification. The dependence on stoichiometric quantities of metals and often organic halides as feedstock precursors, which in turn produces copious amounts of metal halide waste, is the key limitation of the classical organometallic reactions. Inspired by the classical Wolff–Kishner reduction converting carbonyl groups in aldehydes or ketones into methylene derivatives, our group has recently developed strategies to couple various alcohols, aldehydes, and ketones with a broad range of both hard and soft carbon electrophiles in the presence of catalytic amounts of transition metals, via the hydrazone derivatives: i.e., as organometallic reagent surrogates. This Tutorial Review describes the chronological development of this concept in our research group, detailing its creation in the context of a deoxygenation reaction and evolution to a more general carbon–carbon bond-forming strategy. The latter is demonstrated by the employment of carbonyl-derived alkyl carbanions in various transition-metal catalyzed chemical transformations, including 1,2-carbonyl/imine addition, conjugate addition, carboxylation, olefination, cross-coupling, allylation, alkylation and hydroalkylation.

Journal ArticleDOI
TL;DR: The sustainable synthesis of indoloquinazolinone derivatives from N-methoxycarbamoyl indoles and iodonium ylide reagents in methanol is described.

Journal ArticleDOI
TL;DR: In this paper, the crystal structure of lithium cobalt oxide (LiCoO2) found in the cathode materials of spent LIBs was destroyed and converted into lithium carbonate (Li2CO3) and Li-free residue (C/Co3O4) using dry ice as a co-grinding reagent.

Journal ArticleDOI
TL;DR: In this paper, the authors summarized the up-to-date research advancements made in the use of mixed reagent systems to improve the separation efficiency of coal flotation and compared the effects of different mixed collectors on improving the coal separation efficiency at the industrial level application.

Journal ArticleDOI
TL;DR: In this article, a reagent-free electro-Fenton process that runs solely on oxygen and electricity can be achieved by sequential dual-cathode electrocatalysis, where H2O2 is produced on an electrodeposited PEDOT on carbon cloth (PEDOT/CC) cathode and subsequently converted to hydroxyl radicals on a stainless-steel-mesh cathode.
Abstract: Electro-Fenton processes aim at producing oxidizing radicals with fewer added chemicals and residues but are still unable to completely eliminate both. This study demonstrates that a reagent-free electro-Fenton process that runs solely on oxygen and electricity can be achieved by sequential dual-cathode electrocatalysis. H2O2 is produced on an electrodeposited PEDOT on carbon cloth (PEDOT/CC) cathode and subsequently converted to hydroxyl radicals on a stainless-steel-mesh cathode. The dual-cathode system demonstrates efficient decolorization and total organic carbon (TOC) removal toward organic dyes at optimized cathodic potentials of -0.9 V for PEDOT/CC and -0.8 V for the stainless-steel mesh. The sequential dual-cathode process also displays high reusability, no iron leaching, high removal efficiency using air instead of oxygen, and low installation and operation costs. This work demonstrates a preeminent and commercially viable example of pollution control rendered by the "catalysis instead of chemical reagent" philosophy of green chemistry.

Journal ArticleDOI
TL;DR: In this paper, a toolbox of reagents that are capable of the direct introduction of the difluoromethylthio group into the target molecules, including nucleophilic and electrophilic reagents, is presented.
Abstract: Recently, the strategic installation of a fluorine atom or a fluoroalkyl group site-selectively at the specific position of the target molecule has become a routine approach and daily practice for medicinal chemists in their endeavor to fine tune the structure of the lead compound to improve its physicochemical properties such as the cell membrane permeability and metabolic stability. Among many fluoroalkyl groups, the difluoromethylthio group (-SCF2H) has attracted recent intense attention. Largely due to the weak acidity of the proton in the difluoromethylthio group, the difluoromethylthio group is generally considered to be a lipophilic hydrogen-bonding donor and a bioisostere of the hydroxy/thio group that might interact with the heteroatom of the enzyme via a hydrogen bond to improve the binding selectivity of the drug molecule. Besides, the difluoromethylthio group is less lipophilic, less electron-withdrawing, and less stable to the acidic or basic environment than its analogue trifluoromethylthio group (-SCF3), making it easier to regulate the metabolic stability of drug molecules. These beneficial effects render the difluoromethylthio group one of the most favorable functional groups in drug design; consequently, there is an urgent need to develop new strategies for the efficient introduction of the difluoromethylthio group into small molecules under mild conditions. Over the last few decades, several different approaches to the preparation of difluoromethylthiolated compounds have been developed, including the difluoromethylation of thiolated substrates with an electrophilic/nucleophilic difluoromethylating reagent or the insertion of a difluoromethyl carbene into the S-H bond of the thiols. In contrast, we adopt an alternative approach to the preparation of difluoromethylthiolated compounds by late-stage direct difluoromethylthiolation of the specific substrates with a difluoromethylthiolating reagent. With this aim in mind, in the last 6 years we have successfully developed a toolbox of reagents that are capable of the direct introduction of the difluoromethylthio group into the target molecules, including nucleophilic difluoromethylthiolating reagent [(SIPr)AgSCF2H] I, electrophilic difluoromethylthiolating reagent PhthSCF2H II, three optically pure difluoromethylthiolating reagents camphorsultam-SCF2H III, radical difluoromethylthiolating reagent PhSO2SCF2H IV, and reagent PhSO2SCFClH V that could be used for the preparation of 18F-labeled [18F]ArSCF2H. These reagents reacted with a broad range of substrates to get access to difluoromethylthiolated compounds efficiently, thus providing medicinal chemists a powerful weapon for the direct introduction of the difluoromethylthio group into promising molecules during the search for new drugs.

Journal ArticleDOI
Jiabin Shen1, Jun Xu1, Lei He1, Chenfeng Liang1, Wanmei Li1 
TL;DR: The process of selectively introducing a CF3 group into an organic molecule using inexpensive, stable, and solid sodium trifluoromethanesulfinate has rapidly advanced in recent years to become an eco-friendly method used by organic chemists to synthesize various natural and bioactive molecules as mentioned in this paper.

Journal ArticleDOI
Xiu Wang1, Fei Wang1, Fengfeng Huang1, Chuanfa Ni1, Jinbo Hu1 
TL;DR: The 3,3-Difluoro-1,2-diphenylcyclopropene (CpFluor) is a fluorination reagent used in the deoxyfluorination of carboxylic acids to afford various acyl fluorides as discussed by the authors.

Journal ArticleDOI
Zhi-Peng Liang1, Wei Yi1, Peng-Fei Wang1, Gong-Qing Liu1, Yong Ling1 
TL;DR: In this article, a three-component reaction of olefin, diselenide and water, alcohols, phenol, carboxylic acid, or amine by a commercially available hypervalent iodine(III) reagent, PhIO, was developed.
Abstract: A three-component reaction of olefin, diselenide and water, alcohols, phenol, carboxylic acid, or amine by a commercially available hypervalent iodine(III) reagent, PhIO, was developed. This method provides access to a wide range of vicinally functionalized selenoderivatives under ambient conditions with mostly excellent yields and high diastereoselectivity. The developed reaction displays high levels of functional group compatibility and is suitable for the late-stage functionalization of styrene-functionalized biomolecules. Preliminary investigations on the mechanism of the reaction are also presented.

Journal ArticleDOI
Yu Li1, Hefa Cheng1
TL;DR: In this article, the authors investigated the fast oxidation kinetics of a model pollutant, malachite green (MG), in Fenton process in real time using continuous on-line spectrophotometric detection.
Abstract: The oxidation of organic pollutants by Fenton's reagent is commonly considered as a single-stage process that conforms to pseudo first-order kinetics. However, pollutant oxidation would exhibit a two-stage pattern when the initial dosage of Fenton's reagent is sufficiently high. This study investigated the fast oxidation kinetics of a model pollutant, malachite green (MG), in Fenton process in real time using continuous on-line spectrophotometric detection. A chemical kinetic model was further developed, which could well predict the effect of initial concentrations of Fe2+, H2O2, and MG on the degradation of MG in Fenton and solar photo-Fenton processes. The model could also be adapted to model the kinetics of MG mineralization. Modeling results reveal that the significant enhancement in the degradation rate of MG in the second stage of Fenton process by sunlight irradiation was contributed mainly by the production of hydroxyl radicals from H2O2 photolysis. The chemical kinetic model also performed well in describing the degradation and mineralization kinetics of carbendazim and thiabendazole in solar photo-Fenton process. The improved understanding on the fast kinetics of pollutant degradation and the chemical kinetic model developed could help optimize the treatment conditions for organic pollutants in Fenton and solar photo-Fenton processes.

Journal ArticleDOI
TL;DR: In this paper, the authors achieved reagent regeneration energy as low as 1.18 MJ/Kg CO2 with the help of electrodialysis with bipolar membrane separation (EDBM).

Journal ArticleDOI
TL;DR: The synthesis and isolation of several magnesium–cyaphido complexes by reduction of iPr3SiOCP with a magnesium(I) reagent are reported, which can be used for the incorporation of the cyaphide ion into the coordination sphere of metals using a simple salt-metathesis protocol.
Abstract: The cyanide ion plays a key role in a number of industrially relevant chemical processes, such as the extraction of gold and silver from low grade ores. Metal cyanide compounds were arguably some of the earliest coordination complexes studied and can be traced back to the serendipitous discovery of Prussian blue by Diesbach in 1706. By contrast, heavier cyanide analogues, such as the cyaphide ion, C≡P-, are virtually unexplored despite the enormous potential of such ions as ligands in coordination compounds and extended solids. This is ultimately due to the lack of a suitable synthesis of cyaphide salts. Herein we report the synthesis and isolation of several magnesium-cyaphido complexes by reduction of iPr3SiOCP with a magnesium(I) reagent. By analogy with Grignard reagents, these compounds can be used for the incorporation of the cyaphide ion into the coordination sphere of metals using a simple salt-metathesis protocol.

Journal ArticleDOI
TL;DR: In this paper, the authors report the on-demand generation of hexane-soluble (2-ethylhexyl)sodium (1) from 3-(chloromethyl)heptane (2) using a sodium-packed-bed reactor under continuous flow conditions.
Abstract: We report the on-demand generation of hexane-soluble (2-ethylhexyl)sodium (1) from 3-(chloromethyl)heptane (2) using a sodium-packed-bed reactor under continuous flow conditions. Thus, the resulting solution of 1 is free of elemental sodium and therefore suited for a range of synthetic applications. This new procedure avoids the storage of an alkylsodium and limits the handling of metallic sodium to a minimum. (2-Ethylhexyl)sodium (1) proved to be a very useful reagent and undergoes in-line Br/Na-exchanges as well as directed sodiations. The resulting arylsodium intermediates are subsequently trapped in batch with various electrophiles such as ketones, aldehydes, Weinreb-amides, imines, allyl bromides, disulfides and alkyl iodides. A reaction scale-up of the Br/Na-exchange using an in-line electrophile quench was also reported.