- Accessing Ni(III)-thiolate versus Ni(II)-thiyl bonding in a family of Ni-N2S2 synthetic models of NiSOD
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Superoxide dismutase (SOD) catalyzes the disproportionation of superoxide (O2?-) into H2O2 and O2(g) by toggling through different oxidation states of a first-row transition metal ion at its active site. Ni-containing SODs (NiSODs) are a distinct class of this family of metalloenzymes due to the unusual coordination sphere that is comprised of mixed N/S-ligands from peptide-N and cysteine-S donor atoms. A central goal of our research is to understand the factors that govern reactive oxygen species (ROS) stability of the Ni-S(Cys) bond in NiSOD utilizing a synthetic model approach. In light of the reactivity of metal-coordinated thiolates to ROS, several hypotheses have been proffered and include the coordination of His1-Nδ to the Ni(II) and Ni(III) forms of NiSOD, as well as hydrogen bonding or full protonation of a coordinated S(Cys). In this work, we present NiSOD analogues of the general formula [Ni(N2S)(SR′)]-, providing a variable location (SR′ = aryl thiolate) in the N2S2 basal plane coordination sphere where we have introduced o-amino and/or electron-withdrawing groups to intercept an oxidized Ni species. The synthesis, structure, and properties of the NiSOD model complexes (Et4N)[Ni(nmp)(SPh-o-NH2)] (2), (Et4N)[Ni(nmp)(SPh-o-NH2-p-CF3)] (3), (Et4N)[Ni(nmp)(SPh-p-NH2)] (4), and (Et4N)[Ni(nmp)(SPh-p-CF3)] (5) (nmp2- = dianion of N-(2-mercaptoethyl)picolinamide) are reported. NiSOD model complexes with amino groups positioned ortho to the aryl-S in SR′ (2 and 3) afford oxidized species (2ox and 3ox) that are best described as a resonance hybrid between Ni(III)-SR and Ni(II)-?SR based on ultraviolet-visible (UV-vis), magnetic circular dichroism (MCD), and electron paramagnetic resonance (EPR) spectroscopies, as well as density functional theory (DFT) calculations. The results presented here, demonstrating the high percentage of S(3p) character in the highest occupied molecular orbital (HOMO) of the four-coordinate reduced form of NiSOD (NiSODred), suggest that the transition from NiSODred to the five-coordinate oxidized form of NiSOD (NiSODox) may go through a four-coordinate Ni-?S(Cys) (NiSODox-Hisoff) that is stabilized by coordination to Ni(II).
- Broering, Ellen P.,Dillon, Stephanie,Gale, Eric M.,Steiner, Ramsey A.,Telser, Joshua,Brunold, Thomas C.,Harrop, Todd C.
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- First metal- and base-free selective oxidative coupling of thiols in neat ionic liquids: NMR probed "ambiphilic" character of neutral [hmim]Br towards atom-efficient synthesis of disulfides
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The selective oxidative coupling of thiols has been studied in several imidazolium-based ionic liquids in the absence of any base/metal catalysts. Disulfides were obtained from the corresponding thiols in good to excellent yields in 1-hexyl-3-methylimidazolium bromide ([hmim]Br). Furthermore, a 1H NMR-based mechanistic study of the S-S bond formation demonstrated the cooperative role of halide anion and imidazolium cation of [hmim]Br as an "ambiphile" - a character found to be imperative for the efficient syntheses of disulfides. The developed methodology is simple, selective and green that utilises molecular oxygen as an oxidant and produces water as the only by-product. Copyright
- Kumar, Rajesh,Sharma, Nandini,Sharma, Upendra K.,Shard, Amit,Sinha, Arun K.
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- 3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) mediated metal-free mild oxidation of thiols to disulfides in aqueous medium
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Thiols are efficiently oxidized to disulfides (RSSR) in the presence of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) in aqueous medium, as well as in the absence of a solvent under mild and metal-free conditions. A broad range of alkyl, aryl and heterocyclic symmetrical disulfides can be easily obtained in almost quantitative yields. The X-ray single crystal structure of 2-aminocyclopent-1-ene-1-carbothioic dithioperoxyanhydride (disulfide obtained from 2-aminocyclopentene-1-dithiocarboxylic acid, ACDA) is reported. The reaction mechanism has been studied thoroughly. It is shown that the reaction proceeds through the formation of an organosulphur radical. Pytz interacts with thiol to accept one electron and produces an organosulphur radical. Pytz ultimately accepts two electrons to form H2pytz and is capable of oxidizing 2 equivalents of thiols.
- Samanta, Suvendu,Ray, Shounak,Ghosh, Abhisek Brata,Biswas, Papu
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- Reaction of 2,3-epoxyoctafluorobutane with 2-aminobenzenethiol
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The reaction of 2,3-epoxyoctafluorobutane with 2-aminobenzenethiol in N,N-dimethylacetamide gave 3-(2-aminophenylsulfanyl)-1,1,1,3,4,4,4- heptafluorobutane-2,2-diol. In the reaction of the same compounds in dioxane, 2,3-bis(trifluoromethyl)-3,4-dihydro-2H-1,4-benzothiazin-2-ol was formed as a result of primary attack by the amino group in 2-aminobenzenethiol on the epoxy ring. The same product was obtained by treatment with 2-aminobenzenethiol of 2,3-bis(trifluoromethyl)-2H-1,4-benzoxazin-2-ol which was synthesized from 2,3-epoxyoctafluorobutane and 2-aminophenol.
- Saloutina,Zapevalov,Saloutin,Kodess,Kirichenko,Pervova,Chupakhin
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- Bovine serum albumin triggered waste-free aerobic oxidative coupling of thiols into disulphides on water: An extended synthesis of bioactive dithiobis(phenylene)bis(benzylideneimine) via sequential oxidative coupling-condensation reactions in one pot from aminothiophenol and benzaldehyde
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Bovine serum albumin (BSA) has been explored for aerobic oxidative coupling of thiols (aromatic, heterocyclic as well as aliphatic) "on water" towards formation of disulphides (SS) without using any metal/non-metal complexes, bases and additives, which renders the process environmentally benign and economically attractive with good recyclability (up to four cycles). The developed green protocol was further extended for synthesis of diallyldisulphide (DADS), an important constituent of natural occurring allicin. Among various synthesized disulphides, bis(2-aminophenyl)disulphide, obtained by oxidative coupling of 2-aminothiophenol in BSA, was further utilized for condensation with benzaldehyde in the same pot thus enabling easy access to bioactive dithiobis(phenylene)bis(benzyldeneimine). This is the first example of BSA catalysed sequential (oxidation/condensation) reaction where one SS and two CN bonds are formed solely "on water."
- Saima,Lavekar, Aditya G.,Kumar, Rajesh,Sinha, Arun K.
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- Nickel ferrite nanoparticles-hydrogen peroxide: A green catalyst-oxidant combination in chemoselective oxidation of thiols to disulfides and sulfides to sulfoxides
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Nickel ferrite nanoparticles-hydrogen peroxide has been demonstrated for the first time as a green and efficient catalyst-oxidant combination in the chemoselective oxidation of thiols to disulfides and sulfides to sulfoxides. This magnetically separable catalyst was found to be reusable for five consecutive runs without appreciable change in the activity, as well as composition of the catalyst. The mechanism for the oxidation of thiols and sulfides has also been proposed. the Partner Organisations 2014.
- Kulkarni, Aparna M.,Desai, Uday V.,Pandit, Kapil S.,Kulkarni, Makarand A.,Wadgaonkar, Prakash P.
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- Biocatalytic synthesis of diaryl disulphides and their bio-evaluation as potent inhibitors of drug-resistant Staphylococcus aureus
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Staphylococcus aureus is a WHO Priority II pathogen for its capability to cause acute to chronic infections and to resist antibiotics, thus severely impacting healthcare systems worldwide. In this context, it is urgently desired to discover novel molecules to thwart the continuing emergence of antimicrobial resistance. Disulphide containing small molecules has gained prominence as antibacterials. As their conventional synthesis requires tedious synthetic procedure and sometimes toxic reagents, a green and environmentally benign protocol for their synthesis has been developed through which a series of molecules were obtained and evaluated for antibacterial activity against ESKAPE pathogen panel. The hit compound was tested for cytotoxicity against Vero cells to determine its selectivity index and time-kill kinetics was determined. The activity of hit was determined against a panel of S. aureus multi-drug resistant clinical isolates. Also, its ability to synergize with FDA approved drugs was tested as was its ability to reduce biofilm. We identified bis(2-bromophenyl) disulphide (2t) as possessing equipotent antimicrobial activity against S. aureus including MRSA and VRSA strains. Further, 2t exhibited a selectivity index of 25 with concentration-dependent bactericidal activity, synergized with all drugs tested and significantly reduced preformed biofilm. Taken together, 2t exhibits all properties to be positioned as novel scaffold for anti-staphylococcal therapy.
- Saima,Soni, Isha,Lavekar, Aditya G.,Shukla, Manjulika,Equbal, Danish,Sinha, Arun K.,Chopra, Sidharth
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- Sodium Tellurite as a Mild and Selective Oxidizing Agent for Thiols: Its Use in the One-Pot Synthesis of Unsymmetrical Disulfides
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Sodium tellurite acts as a mild and highly selective oxidizing agent for thiols under phase-transfer conditions at room temperature.Aromatic and benzylic thiols are rapidly converted to disulfides.Short-chain primary thiols undergo oxidation in preference to long-chain thiols.Secondary thiols are sluggish in oxidation and tertiary thiols remain intact.No overoxidation of the sulfur atom is observed.Similar results are also obtained with sodium tellurate.
- Suzuki, Hitomi,Kawato, Sei-ichi,Nasu, Akira
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- A new chemodosimetric probe for the selective detection of trivalent cations in aqueous medium and live cells
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A new quinoline functionalized Schiff base (L) was synthesized which displayed selective fluorescence response to trivalent metal cations (Al3+, Fe3+ and Cr3+) over a variety of divalent and monovalent metal cations in ~10
- Samanta, Soham,Goswami, Sudeep,Ramesh, Aiyagari,Das, Gopal
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- Facile Synthesis of Benzo[ d ]azol-2(3 H)-ones Using 2-Phenoxycarbonyl-4,5-dichloropyridazin-3(2 H)-one as Green CO Source
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Developing eco-friendly, stable, and easy-to-handle acyl sources is of great importance in synthetic and green chemistry. This study describes the synthesis of benzo[d]azol-2(3H)-ones such as benzo[d]thiazol-2(3H)-ones, benzo[d]oxazol-2(3H)-ones, and benzo[d]imidazol-2(3H)-ones using 2-phenoxycarbonyl-4,5-dichloropyridazin-3(2H)-one in one pot. The reaction reported is carried out under neutral or acidic conditions in the presence of zinc or sodium bicarbonate to give the corresponding heterocycles in good to excellent yields. The reaction uses a solid stable carbonyl source that is a recyclable functional-group carrier, pyridazin-3(2H)-one.
- Ryu, Ki Eun,Kim, Bo Ram,Sung, Gi Hyeon,Yoon, Hyo Jae,Yoon, Yong-Jin
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- Mild and highly efficient preparation of symmetrical disulfides and diselenides using bipyridinum hydrobromide perbromide as a new oxidative reagent
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A rapid and efficient method for the large-scale synthesis of symmetrical disulfides and diselenides is developed involving oxidative coupling of corresponding thiols and selenols using bipyridinium hydrobromide perbromide (BPHP). Copyright Taylor & Francis Inc.
- Joshaghani,Khosropour,Jafary,Mohammadpoor-Baltork
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- Preparation of benzothiazolyl-decorated nanoliposomes
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Amyloid β (Aβ) species are considered as potential targets for the development of diagnostics/therapeutics towards Alzheimer’s disease (AD). Nanoliposomes which are decorated with molecules having high affinity for Aβ species may be considered as potential carriers for AD theragnostics. Herein, benzothiazolyl (BTH) decorated nanoliposomes were prepared for the first time, after synthesis of a lipidic BTH derivative (lipid-BTH). The synthetic pathway included acylation of bis(2-aminophenyl) disulfide with palmitic acid or palmitoyl chloride and subsequent reduction of the oxidized dithiol derivative. The liberated thiols were able to cyclize to the corresponding benzothiazolyl derivatives only after acidification of the reaction mixture. Each step of the procedure was monitored by HPLC analysis in order to identify all the important parameters for the formation of the BTH-group. Finally, the optimal methodology was identified, and was applied for the synthesis of the lipid-BTH derivative. BTH-decorated nanoliposomes were then prepared and characterized for physicochemical properties (size distribution, surface charge, physical stability, and membrane integrity during incubation in presence of buffer and plasma proteins). Pegylated BTH-nanoliposomes were demonstrated to have high integrity in the presence of proteins (in comparison to non-peglated ones) justifying their further exploitation as potential theragnostic systems for AD.
- Mourtas, Spyridon,Christodoulou, Panayiota,Klepetsanis, Pavlos,Gatos, Dimitrios,Barlos, Kleomenis,Antimisiaris, Sophia G.
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- A novel method for preparation of trifluoromethyl substituted 2,3- dihydro-1,4-diazepine and benzimidazole
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Ethylenediamine reacted readily with 4-ethoxy-1,1,1-trifluoro-3-butene- 2-one to form 5-trifluoromethyl-2,3-dihydro-1,4-diazepine in good yield. Under the same reaction conditions o-phenylene diamine gave 2-trifluoromethyl benzimidazole and benzimidazole.
- Chu, Qianli,Wang, Yanli,Zhu, Shizheng
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- 1,2,4,3,5-benzotrithiadiazepine and its unexpected hydrolysis to unusual 7H,14H-dibenzo[d,i][1,2,6,7,3,8]tetrathiadiazecine
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Previously unknown 1,2,4,3,5-benzotrithiadiazepine 1 was prepared by 1:1 condensation of Ph-N=S=N-SiMe3 with S2Cl2 followed by intramolecular ortho-cyclization of [Ph-N=S=N-S-S-Cl] intermediate, and hydrolyzed in pyridine
- Makarov,Shakirov,Shuvaev,Bagryanskaya,Gatilov,Zibarev
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- Impact of geometric parameters, charge, and lipophilicity on bioactivity of armed quinoxaline, benzothiaole, and benzothiazine: Pom analyses of antibacterial and antifungal activity
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(Equation present) A series of four different armed heterocyclic candidates; 1-(2-methyl-2,3-dihydro-1,3-benzothiazol-2-yl)acetone (2), 1-(3-methyl-4H-1,4-benzothiazin-2-yl)ethanone (3), 2-[(2-aminophenyl)dithio] aniline (4), and 3-hydroxy-3-methyl-4-(3-methyl-2-quinoxalinyl)-2-butanone (5) have been prepared and their microbial activities were evaluated. A correlation of the structure and activities relationships of these compounds with respect to molecular modeling, Lipinski Rule of Five, drug likeness, toxicity profiles, and other physico-chemical properties of drugs are described and verified experimentally. 2014 Copyright Taylor & Francis Group, LLC.
- Hadda, Taibi Ben,Khardli, Fatim Z.,Mimouni, Mostafa,Daoudi, Maria,Kerbal, Abdelali,Salgado-Zamora, Hector,Gandhare, Nilesh,Parvez, Ali,Lahsasni, Siham
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- Synthesis of 2-arylbenzothiazoles via direct condensation between in situ generated 2-aminothiophenol from disulfide cleavage and carboxylic acids
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In this work we describe a simple and efficient general methodology for 2-arylbenzothiazole preparation employing disulfides and carboxylic acids. The reaction is promoted by tributylphosphine that acts both in disulfide bond cleavage and as activating agent for coupling with carboxylic acids. The reaction scope was studied using bis(2-aminophenyl)disulfide and different carboxylic acids with donor/withdrawing substituents, which resulted in the desired 2-arylbenzothiazole with moderate to good yields. The method was tested with success in preparation of the amyloid probe 2-(4-aminophenyl)-6-methoxybenzothiazole that employed a substituted bis(2-aminophenyl)disulfide.
- Coelho, Felipe L.,Campo, Leandra F.
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- Microwave thermolysis I: A convenient and rapid coupling of thiols using 'Clayan' in solvent free condition
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Oxidative coupling of thiols into disulfides using 'Clayan' under microwave irradiation in described. The rapid reaction and dry medium are the important features of the reaction.
- Meshram,Bandyopadhyay,Reddy,Yadav
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- Ball-milling synthesized hydrotalcite supported Cu-Mn mixed oxide under solvent-free conditions: An active catalyst for aerobic oxidative synthesis of 2-acylbenzothiazoles and quinoxalines
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A rapid solvent-free ball-milling method was developed to prepare a hydrophobic hydrotalcite supported Cu-Mn mixed oxide catalyst (Cu-Mn/HT). The mechanochemically prepared catalyst exhibited high catalytic activity and recyclability towards the aerobic synthesis of 2-acylbenzothiazoles and quinoxalines in green medium ethanol compared with the ones synthesized via grinding and wet-impregnation. Moreover, control experiments showed that the catalyst was successfully used in green oxidative esterification and coupling as well. Cu-Mn/HT was characterized by BET, ICP, XRD, XPS, SEM and TEM, which indicated that more surface oxygen vacancies and formed CuMn2O4 species on HT might contribute to the catalytic activity.
- Meng, Xu,Bi, Xiuru,Yu, Chaoying,Chen, Gexin,Chen, Baohua,Jing, Zhenqiang,Zhao, Peiqing
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- Organocatalytic visible light induced S-S bond formation for oxidative coupling of thiols to disulfides
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In this work, we developed a visible light induced oxidative coupling of thiols into the corresponding disulfides in a process catalyzed by an inexpensive and non hazardous Rose Bengal dye. Our optimization study revealed that the use of Rose Bengal catal
- Tankam, Theeranon,Poochampa, Kamolrut,Vilaivan, Tirayut,Sukwattanasinitt, Mongkol,Wacharasindhu, Sumrit
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- Silica-supported bis (trimethylsilyl) chromate: Oxidation of thiols to their corresponding disulfides
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An efficient and convenient method for the oxidation of thiols mediated by silica-supported bis (trimethylsilyl) chromate (BTSC) in acetonitrile is reported. Copyright Taylor & Francis Group, LLC.
- Heravi, Majid M.,Derikvand, Fatemeh,Oskooie, Hossein A.,Shoar, Rahim Hekmat,Tajbakhsh, Mahmood
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- Umpolung Strategy for α,α’-Functionalization of Ketones with 2-Aminothiophenols: Stereoselective Access to Spirobis(1,4-benzothiazines)
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In the presence of TFA as a strong acid catalyst in DMSO, α,α’-enolizable ketones were found to be stereoselectively α,α’-functionalized with 2-aminothiophenols to provide spirobis(1,4-benzothiazine) derivatives. (Figure presented.).
- Nguyen, Thanh Binh,Retailleau, Pascal
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- Copper(II)-catalyzed disulfide scission-stepwise aerobic oxidative cleavage to sulfinate and sulfonate and reductive anaerobic cleavage to thiols
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The Cu(II)-catalyzed oxidative and reductive cleavage of the disulfide bond of N-(2-(2-(2-picolinamido)phenyl)disulfanyl)phenyl)picolinamide, L, is reported for the first time. Aerobic oxidation with Cu(II) gives complete oxidation of S-S bond to sulfonat
- Lumb, Isha,Hundal, Maninder Singh,Hundal, Geeta
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- Synthesis and characterization of N,N'-bis(2-thenylidene)-2,2'- diaminodiphenyl disulfide
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A new compound, N,N'-bis(2-thenylidene)-2,2'-diaminodiphenyl disulfide, known as disulfide compound was synthesised and characterized by IR, UV and 1H-NMR spectroscopy techniques. The crystal and molecular structure determination of the title c
- Ide, Semra,Ancin, Nilguen,Oeztas, Selma Guel,Tuezuen, Muerside
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- Clay catalysis: Condensation of orthoesters with O-substituted aminoaromatics into heterocycles
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KSF clay catalysed the condensation of orthoesters with o-substituted aminoaromatics into heterocycles in toluene under reflux or without solvent under microwave irradiation.
- Villemin, Didier,Hammadi, Mohamed,Martin, Benoit
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- Organic chemistry of superoxide. I. Oxidations of aromatic compounds.
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Potassium superoxide is a selective oxidant for aromatic compounds with the order of susceptibility of substituent groups being -SH>-NH2-OH. Only o- and p- disubstituted amines and phenols are oxidized but monosubstituted thiols react.
- Crank,Makin
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- Structures, Spectroscopic Properties, and Dioxygen Reactivity of 5- and 6-Coordinate Nonheme Iron(II) Complexes: A Combined Enzyme/Model Study of Thiol Dioxygenases
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The synthesis of four new FeII(N4S(thiolate)) complexes as models of the thiol dioxygenases are described. They are composed of derivatives of the neutral, tridentate ligand triazacyclononane (R3TACN; R = Me, iPr) and 2-aminobenzenethiolate (abtx X = H, CF3), a non-native substrate for thiol dioxygenases. The coordination number of these complexes depends on the identity of the TACN derivative, giving 6-coordinate (6-coord) complexes for FeII(Me3TACN)(abtx)(OTf) (1: X = H; 2: X = CF3) and 5-coordinate (5-coord) complexes for [FeII(iPr3TACN)(abtx)](OTf) (3: X = H; 4: X = CF3). Complexes 1-4 were examined by UV-vis, 1H/19F NMR, and M?ssbauer spectroscopies, and density functional theory (DFT) calculations were employed to support the data. M?ssbauer spectroscopy reveals that the 6-coord 1-2 and 5-coord 3- 4 exhibit distinct spectra, and these data are compared with that for cysteine-bound CDO, helping to clarify the coordination environment of the cys-bound FeII active site. Reaction of 1 or 2 with O2 at -95 °C leads to S-oxygenation of the abt ligand, and in the case of 2, a rare di(sulfinato)-bridged complex, [Fe2III(μ-O)((2-NH2)p-CF3C6H3SO2)2](OTf)2 (5), was obtained. Parallel enzymatic studies on the CDO variant C93G were carried out with the abt substrate and show that reaction with O2 leads to disulfide formation, as opposed to S-oxygenation. The combined model and enzyme studies show that the thiol dioxygenases can operate via a 6-coord FeII center, in contrast to the accepted mechanism for nonheme iron dioxygenases, and that proper substrate chelation to Fe appears to be critical for S-oxygenation.
- Gordon, Jesse B.,McGale, Jeremy P.,Prendergast, Joshua R.,Shirani-Sarmazeh, Zahra,Siegler, Maxime A.,Jameson, Guy N. L.,Goldberg, David P.
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- Ecofriendly syntheses of phenothiazones and related structures facilitated by laccase – a comparative study
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The biocatalytic synthesis of phenothiazones and related compounds has been achieved in an aqueous system under mild conditions facilitated by laccase oxidation. It was found that by coupling 2-aminothiophenol directly with 1,4-quinones, the product yield
- Cannatelli, Mark D.,Ragauskas, Arthur J.
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- A selective proton transfer optical sensor for copper II based on chelation enhancement quenching effect (CHEQ)
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A novel selective fluorescent sensor for Cu2+ in solution has been developed by means of chelation enhancement quenching effect (CHEQ). The compound N,N′-bis(salycilidene)-(2-(3′,4′-diaminophenyl)benzothiazole (BTS) is reactive to intramolecular proton transfer on the electronic excited state (ESIPT) presenting fluorescence emission in the blue region with very large Stokes shift (8794 cm?1). Spectroscopic titration experiments indicate that not only the fluorescence quenching but also of the ESIPT reaction allowed naked eye detection as a paper strip-based sensor. This chemosensor showed to be selective to Cu2+ among 13 other cations. The sensor:Cu2+ ratio was determined by both Job and Benesi-Hildebrand plots as 1:2. In addition, the binding between sensor and metal was investigated by 1H NMR, FTIR and HRMS in order to elucidate the formed complex and corroborate the results of BTS:Cu2+ ratio. The binding constant was also found as 3.0 × 1010 mol?2 L2 at 25 °C. The detection and quantification limits were also obtained as 32 ppb and 108 ppb, respectively.
- Berbigier, J?natas Faleiro,Coelho, Felipe Lange,Gamino da Costa, Gabriela,Germino, José Carlos,Rodembusch, Fabiano Severo,Teixeira Alves Duarte, Luís Gustavo,Zambon Atvars, Teresa Dib
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- Metalloclayzymes: An efficient oxidative coupling of thiols catalysed by FE (III) montmorillonite in buffer
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An effcient S-S bond formation is described in buffer solution (pH 7.2) catalysed by Fe(III) ion exchanged montmorillonite.
- Meshram,Kache, Rajashaker
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- A route to fluorocontaining N,S-heterocycles via octafluoro-2,3-epoxybutane
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The reaction of octafluoro-2,3-epoxybutane 1 with 2-aminothiophenol gave three kinds of novel fluorocontaining N,S-heterocyclic compounds depending on the solvent nature: 2,3-bis(trifluoromethyl)-3,4-dihydro-2H-1,4-benzothiazin-2-ol 2, 2-trifluoromethyl-2-[1-(2-aminophenylthio)-2,2,2-trifluoroethyl]-1,3-ben zothiazolidine 6 and 5a,11a-bis(trifluoromethyl)-5a,6,11a,12-tetrahydro-5,11-dithia-6,12-diaz anaphthacene 5. Use of the toluene, dioxane, tetrahydrofuran, acetonitrile and dimethoxyethane gave the unexpected dihydrobenzothiazine 2 (RS,SR > RR,SS) in good to moderate yields. In dimethylsulfoxide and N,N-dimethylacetamide, unusual cyclization occurred resulting in benzothiazolidine 6 (RS,SR/RR,SS ~ 1:1) in moderate yields. Formation of minor 1,1,1,3,4,4,4-heptafluoro-3-(2-aminophenylthio)-2,2-dihydroxybutane 4 which was converted into bis(benzothiazine) 5 was observed in all solvents tested with the exception of toluene and dioxane. The molecular structure of the RS,SR-diastereomer of dihydrobenzothiazine 2, bis(benzothiazine) 5 and the RS,SR-diastereomer of benzothiazolidine 6 has been established by X-ray crystallography.
- Saloutina, Lyudmila V.,Zapevalov, Aleksandr Ya.,Saloutin, Victor I.,Slepukhin, Pavel A.,Kodess, Mikhail I.,Kirichenko, Valentina E.,Pervova, Marina G.,Chupakhin, Oleg N.
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- The rearrangement of trifluoroacetylchromenes to trifluoromethylchromenols
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[Figure not available: see fulltext.] The reaction of o-phenylenediamine with condensed 4H-pyrans containing a trifluoroacetyl group at the β-position relative to the oxygen atom led to 2-(trifluoromethyl)chroman-2-ols and 3-(trifluoromethyl)-2,3-dihydro-1H-benzo[f]chromen-3-ols via a cascade process that was initiated by a Michael reaction.
- Osyanin, Vitaly A.,Popova, Yulia V.,Sakhnenko, Darina V.,Osipov, Dmitry V.,Klimochkin, Yuri N.
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- Baker's yeast catalyzed synthesis of 1,4-benzothiazines, performed under ultrasonication
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An efficient and simple one pot method has been developed for the synthesis of 1,4-benzothiazines by allowing the condensation of 2-aminobenzenethiols and 1,3-dicarbonyls using cheaper biocatalyst, baker's yeast. The role of ultrasonication in the rate expediting of the condensation has been discussed.
- Pratap, Umesh R.,Jawale, Dhanaji V.,Londhe, Balaji S.,Mane, Ramrao A.
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- Synthesis and Characterization of Disulfide-Schiff Base Derivatives and in vitro Investigation of Their Antibacterial Activity Against Multidrug-Resistant Acinetobacter baumannii Isolates: A New Study
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In this study two different methods without a catalyst and with a CeO2 nano catalyst were used for the synthesis of dimeric disulfide-Schiff bases. The dimeric disulfide-Schiff base derivatives were characterized by FT-IR, NMR, and MS spectra, and elemental analysis. The disulfide-Schiff bases and their derivatives 2–5c were screened for in vitro antibacterial activity against 40 multidrug-resistant strains of Acinetobacter baumannii, and their minimum inhibitory concentrations were determined. Most of products exhibited high antibacterial activity against Acinetobacter baumannii.
- Durmus,Dalmaz,Cal?skan,Dulger
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- New 3,1,2,4-benzothiaselenadiazines, related π-heterocycles including Herz cations, radicals and molecular complexes, and Bunte salts
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New chalcogen-nitrogen π-heterocycles covering 3,1,2,4-benzothiaselenadiazines, 1,3,2,4-benzodithiadiazines and 1,2,4,3,5-benzotrithiadiazepines were synthesized via the electrophilic cyclization of compounds Ar-NSN-SiMe3 under the action of SeCl2, SeCl4/FeCp2, SCl2 and S2Cl2. Heterocycles obtained were thermolyzed into persistent 2,1,3-benzothiaselenazolyls and 1,2,3-benzodithiazolyls (Herz radicals), which were characterized using EPR spectroscopy and DFT calculations. Reaction of the archetypal 3,1,2,4-benzothiaselenadiazine with SCl2 afforded 2,1,3-benzothiaselenazolium chloride (Herz salt), whereas that of sterically hindered 1,3,2,4-benzodithiadiazine resulted in a complex of the corresponding Herz salt with unexpected carbocycle-chlorinated and non-chlorinated 3,3-dioxides of the starting material, which is a rare example of a molecular complex involving a Herz cation. Formation of the dioxides can be explained through intermediate participation of the benzodithiadiazine radical cation. Hydrolysis of 3,1,2,4-benzothiaselenadiazine or 1,3,2,4-benzodithiadiazine led to Se-(2-aminophenyl)selenosulfate (Se-Bunte salt) or S-(2-aminophenyl)thiosulfate (Bunte salt), respectively. This journal is
- Bagryanskaya, Irina Yu.,Gatilov, Yuri V.,Irtegova, Irina G.,Makarov, Alexander Yu.,Nefedov, Andrey A.,Volkova, Yulia M.,Zibarev, Andrey V.,Zikirin, Samat B.
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p. 3687 - 3696
(2022/03/07)
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- Synthesis and Characterization of Magnetic Functionalized Ni and Cu Nano Catalysts and Their Application in Oxidation, Oxidative Coupling and Various Multi-Component Reactions
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Abstract: Two magnetic nano catalysts of nickel and copper, Fe3O4@SiO2@DOP-BenPyr-M(II), (M=Ni and Cu) have been synthesized. These catalysts were applied as recoverable, efficient and new heterogeneous catalysts for the high yielding and room temperature one-pot procedure of selective oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides. In addition, the catalytic activity of Fe3O4@SiO2@DOP-BenPyr-Ni(II) was investigated as heterogeneous nanocatalyst for synthesis of 2,3-dihydroquinazolin-4(1H)-ones, 5-substituted 1H-tetrazoles and polyhydroquinolines. The synthesized catalysts were characterized by FT-IR, TGA, XRD, VSM, EDX, ICP and SEM techniques. These catalysts were recovered by an external magnet and reused several times without significant loss of catalytic efficiency. Graphic Abstract: [Figure not available: see fulltext.]
- Hajjami, Maryam,Sheikhaei, Shiva,Gholamian, Fatemeh,Yousofvand, Zakieh
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p. 2420 - 2435
(2021/01/04)
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- A green disulfide synthesis method
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The present invention discloses a green disulfide synthesis method, belonging to the field of green chemical and organic synthesis technology. Under room temperature, open, neutral conditions, rapid preparation of parent nuclei is alkanes, olefins, aromatic hydrocarbons, oxazole, thiazole, pyrazole, imidazole, etc. and their derivatives of symmetrical disulfide, the catalyst is MBrx(M is Fe2+,Fe3+,Ce3+, etc., x is 2-3), the only oxidant isH2O2. The present invention is reacted by using commercially available and low-cost reagents (e.g., FeBr2,CeBr3 andH2O2,etc.) and common organic solvents, the steps are concise, the operation is convenient, the reaction is rapid, the reaction conditions are mild, the room temperature is open, and no further purification can be obtained pure disulfide, more advantageous than all previous methods, is expected to be in organic synthesis, medicine, Pesticides and electronics and other industries are widely used.
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Paragraph 0031-0033
(2022/01/08)
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- Synthesis and biological evaluation of disulfides as anticancer agents with thioredoxin inhibition
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Altered redox homeostasis as a hallmark of cancer cells is exploited by cancer cells for growth and survival. The thioredoxin (Trx), an important regulator in maintaining the intracellular redox homeostasis, is cumulatively recognized as a promising target for the development of anticancer drugs. Herein, we synthesized 72 disulfides and evaluated their inhibition for Trx and antitumor activity. First, we established an efficient and fast method to screen Trx inhibitors by using the probe NBL-SS that was developed by our group to detect Trx function in living cells. After an initial screening of the Trx inhibitory activity of these compounds, 8 compounds showed significant inhibition activity against Trx. We then evaluated the cytotoxicity of these 8 disulfides, compounds 68 and 69 displayed high cytotoxicity to HeLa cells, but less sensitive to normal cell lines. Next, we performed kinetic studies of both two disulfides, 68 had faster inhibition of Trx than 69. Further studies revealed that 68 led to the accumulation of reactive oxygen species and eventually induced apoptosis of Hela cells via inhibiting Trx. The establishment of a method for screening Trx inhibitors and the discovery of 68 with remarkable Trx inhibition provide support for the development of anticancer candidates with Trx inhibition.
- Wei, Xiangxu,Zhong, Miao,Wang, Song,Li, Lexun,Song, Zi-Long,Zhang, Junmin,Xu, Jianqiang,Fang, Jianguo
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- Acyl Derivatives of Eudesmanolides To Boost their Bioactivity: An Explanation of Behavior in the Cell Membrane Using a Molecular Dynamics Approach
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Semisynthetic analogs of natural products provide an important approach to obtain safer and more active drugs and they can also have enhanced physicochemical properties such as persistence, cross-membrane processes and bioactivity. Acyl derivatives of different natural product families, from sesquiterpene lactones to benzoxazinoids, have been synthesized and tested in our laboratories. These compounds were evaluated against tumoral and nontumoral cell lines to identify selective derivatives with a reduced negative impact upon application. The mode of action of these compounds was analyzed by anti-caspase-3 assays and molecular dynamics simulations with cell membrane re-creation were also carried out. Aryl derivatives of eudesmanolide stand out from the other compounds and are better than current anticancer drugs such as etoposide in terms of selectivity and activity. Computational studies provide evidence that lipophilicity plays a key role and the 4-fluorobenzoyl derivative can pass easily through the cell membrane.
- Mejías, Francisco J. R.,Durán, Alexandra G.,Zorrilla, Jesús G.,Varela, Rosa M.,Molinillo, José M. G.,Valdivia, Manuel M.,Macías, Francisco A.
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p. 1297 - 1307
(2021/02/09)
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- Accelerated reduction and solubilization of elemental sulfur by 1,2-aminothiols
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Nucleophilic 1,2-aminothiol compounds readily reduce typically-insoluble elemental sulfur to polysulfides in both water and nonpolar organic solvents. The resulting anionic polysulfide species are stabilized through hydrogen-bonding interactions with the proximal amine moieties. These interactions can facilitate sulfur transfer to alkenes.
- Stoffel, Jonathan T.,Riordan, Kimberly T.,Tsui, Emily Y.
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supporting information
p. 12488 - 12491
(2021/12/04)
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- Elemental Sulfur-Promoted Benzoxazole/Benzothiazole Formation Using a C=C Double Bond as a One-Carbon Donator
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An efficient method to assemble diverse benzoxazoles/benzothiazoles in good yields was developed via oxidative cyclization with 2-aminothiophenols or 2-iodoanilines as raw materials. In this protocol, elemental sulfur was used as the effective oxidant and C atoms on the C=C double bond were introduced as a one-carbon donator.
- Chen, Xuecheng,Han, Shiqing,Hu, Liang,Liu, Yafei,Luo, Yue,Pan, Bin,Peng, Yalan,Zhang, Jun,Zhang, Yurong
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p. 14485 - 14492
(2021/11/12)
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- Preparation and characterization of Cu (II) Schiff base complex functionalized boehmite nanoparticles and its application as an effective catalyst for oxidation of sulfides and thiols
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The synthesis, characterization, and evaluation of a Schiff base Cu (II) complex functionalized boehmite nanoparticles (Cu-complex-boehmite) as a new catalyst for oxidation of sulfides and thiols in the presence of hydrogen peroxide with complete selectivity and high conversion under solvent-free and mild reaction conditions were reported. Characterization of the catalyst was performed with various physicochemical methods. This effective catalyst was evaluated in terms of activity and reusability. It indicated high catalytic activity, good recoverability and reusability, and supplied the corresponding products in high yields and short reaction times. In addition, it shows notable advantages such as simplicity of operation, heterogeneous nature, easy work up, and it could be used at least eight times with no significant loss of its activity.
- Khodaei, Mohammad Mehdi,Alizadeh, Abdolhamid,Afshar Hezarkhani, Hadis
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- Environmentally Benign Large-Scale Synthesis of a Precursor to Vortioxetine
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An eco-friendly, high-yielding, and transition-metal-free synthesis of 2-[(2,4-dimethylphenyl)thio]aniline precursor to vortioxetine is reported. Vortioxetine, a multi-modal acting drug with high affinity for a range of serotonergic targets, is used for the treatment of major depressive disorder (MDD). The synthesis - applicable in multi-gram scale - involves the reaction of bis(2,4-dimethyl)iodonium bromide with commercial 2-aminophenyl disulfide, whereas its reaction with 2-aminothiophenol afforded the same product but in low to moderate yields. This method works equally well in deep eutectic solvents (DESs), based on choline chloride (ChCl).
- Zisopoulou, Stavroula A.,Pafili, Anastasia E.,Gkizis, Petros,Andreou, Thanos,Koftis, Theoharis V.,Lithadioti, Alexandra,Neokosmidis, Efstratios,Gallos, John K.
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p. 2662 - 2666
(2020/09/15)
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- Natural gallic acid catalyzed aerobic oxidative coupling with the assistance of MnCO3 for synthesis of disulfanes in water
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The formation of S-S bonds has great significance and value in synthetic chemistry and bioscience. To pursue a sustainable approach for such a synthesis, an aerobic oxidative coupling method for the efficient preparation of organic disulfanes, using a low-toxic natural gallic acid as an organocatalyst, inexpensive MnCO3 as a cocatalyst, O2 as the terminal oxidant and water as the solvent, has been successfully developed. Such metal-organic cooperative catalytic protocol provided an access to various symmetrical and unsymmetrical disulfanes in up to 99% yield. Gram scale synthesis with practical convenience and low loading of catalysts further illustrates the practicability of our method.
- Song, Lijuan,Li, Wenhao,Duan, Wenxue,An, Jichao,Tang, Shanyu,Li, Longjia,Yang, Guanyu
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supporting information
p. 1432 - 1438
(2019/03/26)
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- Transition Metal-Free Oxidative Coupling of Primary Amines in Polyethylene Glycol at Room Temperature: Synthesis of Imines, Azobenzenes, Benzothiazoles, and Disulfides
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A transition metal-free protocol has been developed for the oxidative coupling of primary amines to imines and azobenzenes, thiols to disulfides, and 2-aminothiophenols to benzothiazoles, offering excellent yields. The advantageous features of the present environmentally benign methodology include the usage of biocompatible and green reaction conditions such as, solvent, room temperature reactions and transition metal-free approach. Moreover, it offers a broader substrate scope.
- Hudwekar, Abhinandan D.,Verma, Praveen K.,Kour, Jaspreet,Balgotra, Shilpi,Sawant, Sanghapal D.
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p. 1242 - 1250
(2019/01/09)
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- Conversion of anilines into azobenzenes in acetic acid with perborate and Mo(VI): correlation of reactivities
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Azobenzenes are extensively used to dye textiles and leather and by tuning the substituent in the ring, vivid colours are obtained. Here, we report preparation of a large number of azobenzenes in good yield from commercially available anilines using sodium perborate (SPB) and catalytic amount of Na2MoO4 under mild conditions. Glacial acetic acid is the solvent of choice and the aniline to azobenzene conversion is zero, first and first orders with respect to SPB, Na2MoO4 and aniline, respectively. Based on the kinetic orders, UV–visible spectra and cyclic voltammograms, the conversion mechanism has been suggested. The reaction rates of about 50 anilines at 20–50?°C and their energy and entropy of activation conform to the isokinetic or Exner relationship and compensation effect, respectively. However, the reaction rates, deduced by the so far adopted method, fail to comply with the Hammett correlation. The specific reaction rates of molecular anilines, obtained through a modified calculation, conform to the Hammett relationship. Thus, this work presents a convenient inexpensive non-hazardous method of preparation of a larger number of azobenzenes, and shows the requirement of modification in obtaining the true reaction rates of anilines in acetic acid and the validity of Hammett relationship in the conversion process, indicating operation of a common mechanism.
- Karunakaran,Venkataramanan
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p. 375 - 385
(2019/02/14)
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- Unsymmetrical Disulfides Synthesis via Sulfenium Ion
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An umpolung approach for the synthesis of unsymmetrical disulfides via sulfenium ion is reported. In situ generated electrophilic sulfenium ion from electron-rich thiols reacted with second thiols to yield unsymmetrical disulfides. Using an iodine catalyst and 4-dimethylaminopyridine (DMAP)/water as promoter, the target syntheses were achieved in one pot under aerobic condition.
- Parida, Amarchand,Choudhuri, Khokan,Mal, Prasenjit
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supporting information
p. 2579 - 2583
(2019/07/15)
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- Industrialized preparation method of rubber peptizer DBD
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The invention relates to a preparation method of a rubber aid, and particularly discloses a novel preparation method of a rubber peptizer DBD. The industrialized preparation method of the rubber peptizer DBD is characterized by comprising the following steps: 1) producing 2,2-dinitrodisulfide by using o-nitrochlorobenzene and sodium polysulfide under the heating reflux condition; 2) adding aceticacid to reduce the 2,2-dinitrodisulfide into diphenyl aminodisulfide; and 3) adding benzoyl chloride and an acid-binding agent into the product obtained in the step 2) in a mixed solvent to obtain theDBD. In the process, the step 1) and the step 2) are conducted continuously, and separation and purification are not needed. The step 3) can be conducted only through simple separation of the productin the step 2), purification is not needed, and the process is simplified greatly; furthermore, yield loss caused by purification is reduced; in addition, the mixed solvent and the triethylamine canbe recycled and the whole process is little in discharge.
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Paragraph 0017; 0018; 0019; 0020
(2018/06/21)
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- Preparation method and application of aromatic disulfide capable of triggering, polymerizing and lowering volume shrinkage
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The invention relates to synthesis and application of aromatic disulfide having the volume shrinkage triggering, polymerizing and lowering functions. The synthesis comprises the following steps that an aromatic sulfhydryl compound with active hydrogen and
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Paragraph 0023; 0024
(2018/11/03)
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- Synthesis and characterization of oxo-vanadium complex anchored onto SBA-15 as a green, novel and reusable nanocatalyst for the oxidation of sulfides and oxidative coupling of thiols
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Abstract: The present work describes the synthesis of a new oxo-vanadium complex immobilized on SBA-15 nanostructure as an efficient catalyst for oxidation of sulfides and oxidative coupling of thiols. Characterization of the resultant AMPD@SBA-15 nanostructure was performed by various physico-chemical techniques such as Fourier transform infrared spectroscopy, transmission and scanning electron microscopies, energy-dispersive X-ray spectroscopy, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, thermal gravimetric analysis, and N2 adsorption and desorption. The results of the developed procedure bring several benefits such as the use of commercially available, ecologically benign, operational simplicity, and cheap and chemically inert reagents. It shows good reaction times, practicability and high efficiency, and is easily recovered from the reaction mixture by simple filtration and reused for several consecutive cycles without noticeable change in its catalytic activity. More importantly, high efficiency, simple and an inexpensive procedure, commercially available materials, easy separation, and an eco-friendly procedure are the several advantages of the currently employed heterogeneous catalytic system.
- Tamoradi, Taiebeh,Ghadermazi, Mohammad,Ghorbani-Choghamarani, Arash,Molaei, Somayeh
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p. 4259 - 4276
(2018/03/21)
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- Synthesis and characterization of sulfamic acid supported on Fe3O4 nanoparticles: A green, versatile and magnetically separable acidic catalyst for oxidation reactions and Knoevenagel condensation
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Sulfamic acid immobilized on diethylenetriamine functionalized Fe3O4 nanoparticles (SA-DETA-Fe3O4) was successfully prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), thermo gravimetric analysis (TGA), X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The sulfamic acid was found as a magnetically separable and highly active catalyst for the oxidative coupling thiols, oxidation of sulfides. Furthermore, the SA-DETA-Fe3O4 showed the high catalytic activity in Knoevenagel condensation of aromatic aldehydes with active methylene compounds (malononitrile and ethyl cynoacetate). The nanosolid catalyst could be easily recovered by a simple magnetic separation and reused for many cycles without deterioration in catalytic activity.
- Shiri, Lotfi,Narimani, Hojatollah,Kazemi, Mosstafa
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- An Organodiselenide with Dual Mimic Function of Sulfhydryl Oxidases and Glutathione Peroxidases: Aerial Oxidation of Organothiols to Organodisulfides
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A novel organodiselenide, which mimics sulfhydryl oxidases and glutathione peroxidase (GPx) enzymes for oxidation of thiols by oxygen and hydrogen peroxide, respectively, into disulfides has been presented. The developed catalyst oxidizes an array of organothiols into respective disulfides in practical yields by using aerial O2 to avoid any reagents/additives, base, and light source. The synthesized diselenide also catalyzes the reduction of hydrogen peroxide into water by following the GPx enzymatic catalytic cycle with a reduction rate of 49.65 ± 3.7 μM·min-1.
- Rathore, Vandana,Upadhyay, Aditya,Kumar, Sangit
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supporting information
p. 6274 - 6278
(2018/10/05)
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- PTAB mediated open air synthesis of sulfonamides, thiosulfonates and symmetrical disulfanes
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A facile methodology has been described which has successfully simplified the generation of sulfonamides, thiosulfonates and symmetric disulfanes. This “trio” of reactions occur in an open air metal free atmosphere and has also been scaled up to grams making it suitable for commercialization. The reactions also have been successfully carried out with asymmetric variants, thus contributing to the chiral pool. The user friendly “trio” enables easy generation of these versatile sulfur analogues and the reaction condition employed depict an economic outline.
- Sarkar, Debayan,Ghosh, Manoj Kumar,Rout, Nilendri
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supporting information
p. 2360 - 2364
(2018/05/24)
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- A novel dual-nano assisted synthesis of symmetrical disulfides from aryl/alkyl halides
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Here, we have reported a novel approach towards dual-nano assisted synthesis of disulfides from coupling of alkyl/aryl halides and sulfur nanoparticles. The indium oxide nanoparticles as catalyst expedite the conversion and sulfur nanoparticle notably enhances the miscibility, providing a faster, high yielding and cost-effective process in ethanol-water system. The method has synthetic advantages in terms of mild reaction framework, catalyst regeneration, and absence of any sulfide or polysulfide linkage as by-product leading to a column free synthesis. A variety of alkyl, aryl and heteroaryl symmetrical disulfides are obtained in good to excellent yields up to exceeding 98%.
- Devi, Namita,Hazarika, Sukanya,Gogoi, Prasanta,Barman, Pranjit
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p. 1927 - 1938
(2018/07/21)
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- Elemental Sulfur-Mediated Decarboxylative Redox Cyclization Reaction: Copper-Catalyzed Synthesis of 2-Substituted Benzothiazoles
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A S 8 -mediated directed decarboxylative redox-cyclization strategy for the synthesis of 2-substituted benzothiazoles from o -iodoanilines, arylacetic acids, and elemental sulfur catalyzed by cheap copper metal has been developed. This reaction is operationally simple, ligand-free, compatible with a wide range of functional groups, and provides the desired products in good to excellent yields. In addition, a gram-scale experiment was carried out to furnish PMX 610, an antitumor drug.
- Wang, Xin,Li, Xiaotong,Hu, Renhe,Yang, Zhao,Gu, Ren,Ding, Sai,Li, Pengyi,Han, Shiqing
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supporting information
p. 219 - 224
(2017/10/09)
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- 2-Arylation/alkylation of benzothiazoles using superparamagneticgraphene oxide-Fe3O4 hybrid material as a heterogeneous catalystwith diisopropyl azodicarboxylate (DIAD) as an oxidant
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In this report, we introduced Graphene oxide-iron oxide (GO-Fe3O4) nanocomposites as a heterogeneous catalyst for arylation/alkylation of benzothiazoles with aldehydes and benzylic alcohols in the presence of diisopropyl azodicarboxylate (DIAD) as an oxidant which exclusively produced 2-aryl (alkyl)-1H–benzothizoles in moderate to excellent yields. The absence of precious metals and toxic solvent, easy product isolation, and recyclability of the GO-Fe3O4 with no loss of activity are notable advantages of this method.
- Khalili, Dariush,Etemadi-Davan, Elham,Banazadeh, Ali Reza
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- Fe3O4 MNPs-DETA/Benzyl-Br3: A new magnetically reusable catalyst for the oxidative coupling of thiols
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We report a new strategy to immobilize a bromine source on the surface of magnetic Fe3O4 nanoparticles (Fe3O4 MNPs-DETA/Benzyl-Br3) leading to amagnetically recoverable catalyst, which exhibits high catalytic efficiency in oxidative coupling of thiols to the disulfides (89–98%). The Fe3O4 MNPs-DETA/Benzyl-Br3 catalyst was fabricated by anchoring 3-chloropropyltrimethoxysilane (CPTMS) onmagnetic Fe3O4 nanoparticles, followed with N-benzylation and reaction with bromine in tetrachloridecarbon. The resulting nanocomposite was analyzed by a series of characterization techniques such as FT-IR, SEM, TGA, VSM and XRD. The catalyst could be recovered viamagnetic attraction and could be recycled at least 5 times without appreciable decrease in activity.
- Shiri, Lotfi,Kazemi, Mosstafa
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p. 1171 - 1176
(2017/09/27)
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- Synthesis and characterization of tribenzyl ammonium-tribromide supported on magnetic Fe3O4 nanoparticles: a robust magnetically recoverable catalyst for the oxidative coupling of thiols and oxidation of sulfides
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Abstract: Taking into account the principles of green chemistry, magnetic nanoparticles, especially Fe3O4 nanoparticles, open up a new chapter in modern organic synthesis to inset a fascinating, stupendous and efficient catalytic strategy for facilitating catalyst recovery in various chemical reactions. Inspired by this topic, tribenzyl ammonium-tribromide immobilized on magnetic nanoparticles (Fe3O4–TBA-Br3) as a bromine source was successfully synthesized and its catalytic activity in the oxidative coupling of thiols and oxidation of sulfides was investigated. It is the first report on the use of the immobilized bromine source on Fe3O4 nanoparticles as a nanomagnetic recyclable catalyst for the oxidative coupling of thiols. The nanosolid catalyst could be easily recovered by a simple magnetic separation and reused for several cycles without significant degradation in catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]
- Shiri, Lotfi,Ghorbani-Choghamarani, Arash,Kazemi, Mosstafa
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p. 2707 - 2724
(2017/04/18)
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- Synthesis of Fe3O4@SiO2@DOPisatin-Ni(II) and Cu(II) nanoparticles: Highly efficient catalyst for the synthesis of sulfoxides and disulfides
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The catalytic activity of two magnetic catalysts Fe3O4@SiO2@DOPisatin-M(II) (M?=?Ni, Cu) was investigated in the environmentally green H2O2 oxidant-based oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides. By using these catalysts, various substrates were successfully converted into their corresponding product. These catalysts could also be reused multiple time without significant loss of activity. The physical and chemical properties of the catalysts were determined using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS).
- Hajjami, Maryam,Sharifirad, Fatemeh,Gholamian, Fatemeh
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- Dialkyl Dicyanofumarates as Oxidizing Reagents for the Conversion of Thiols into Disulfides and Selenols into Diselenides
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Aliphatic and aromatic thiols react smoothly with dialkyl dicyanofumarates in CH2Cl2 at room temperature to give the corresponding disulfides in excellent yields. Aliphatic 1,2-, 1,3-, and 1,4-dithiols afford cyclic disulfides. Analogous reaction courses were observed for selenols, and the required diselenides also formed in nearly quantitative yields. In all of the reactions, dialkyl dicyanosuccinates formed as 1:1 mixtures of diastereoisomers as the only other product. Cysteamine (2-mercaptoethylamine) behaved differently; the Michael addition of the primary amine group led to the complete consumption of the dicyanofumarate, and the formation of the disulfide containing an enamine moiety occurred without the formation of dicyanosuccinate.
- Mlostoń, Grzegorz,Capperucci, Antonella,Tanini, Damiano,Hamera-Fa?dyga, Ró?a,Heimgartner, Heinz
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p. 6831 - 6839
(2017/09/11)
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- Highly chemoselective reduction of azides to amines by Fe(0) nanoparticles in water at room temperature
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A highly chemoselective reduction of aryl, heteroaryl, acyl and sulfonyl azides to the corresponding amines has been achieved by Fe(0) nanoparticles in water at room temperature in the absence of external hydride source. Several readily reducible functionalities including alkene, alkyne, S-S linkage, OTBDMS remain unaffected during reduction.
- Panja, Subir,kundu, Debasish,Ahammed, Sabir,Ranu, Brindaban C.
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supporting information
p. 3457 - 3460
(2017/08/10)
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- Rubber peptizer SS preparation method
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The invention provides a rubber peptizer SS preparation method. The rubber peptizer SS preparation method includes the steps of subjecting benzothiazole and sodium hydroxide to high-temperature decomposition reaction so as to prepare a sodium aminothiophenol solution; dropwise adding a mixed acid solution prepared from water, sulfuric acid and hydrogen peroxide into the sodium aminothiophenol solution at 35-40 DEG C prior to oxidation reaction, and filtering to obtain DS (2,2'-diphenylamine disulphide) after the oxidation reaction is completed; adding the DS and the water into a reaction kettle, adding sodium carbonate, stirring to increase the temperature to 90-95 DEG C, dropwise adding benzoyl chloride for acylation reaction, cooling after the reaction is completed, performing solid-liquid separation and alcohol washing, and drying at 50 DEG C so as to obtain the SS (2,2'-dibenzoyl diphenyl disulfide). The rubber peptizer SS preparation method has the advantages that the raw materials are free of toxicity, cheap and easily available, and a technological process is simple and easy to operate; toxic solvents are unused, and accordingly a preparation workshop is low in toxicity and less polluted; high yield and high quality are achieved, so that the rubber peptizer SS is promising in market prospect; since the alcohol solvents can be recycled, overall cost is low and rubber peptizer SS purity can be above 98%.
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- Efficient preparation of boehmite silica dopamine sulfamic acid as a novel nanostructured compound and its application as a catalyst in some organic reactions
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A novel type of recoverable boehmite nanocatalyst was prepared via immobilization of dopamine on the surface of boehmite followed by coating with silica and reacting with chlorosulfunic acid to obtain boehmite silica dopamine sulfamic acid (boehmite-Si-DSA). This compound was characterized by FT-IR spectroscopy, TGA, XRD, TEM and SEM techniques. Boehmite-Si-DSA was used as an efficient, recoverable and thermally stable heterogeneous nanocatalyst for the preparation of 2,3-dihydroquinazolin-4(1H)-one, sulfoxides and disulfides. The catalyst was recovered by simple filtration and reused several times without significant loss of catalytic efficiency.
- Hajjami, Maryam,Ghorbani-Choghamarani, Arash,Ghafouri-Nejad, Raziyeh,Tahmasbi, Bahman
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p. 3066 - 3074
(2016/05/09)
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- Boehmite silica sulfuric acid: as a new acidic material and reusable heterogeneous nanocatalyst for the various organic oxidation reactions
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In this research, project boehmite silica sulfuric acid (Boehmite-SSA) has been applied as new acidic porous catalyst for the selective oxidation of sulfides to sulfoxides and oxidative coupling of thiols to corresponding disulfides using hydrogen peroxide as oxidizing agent. The products have been obtained in short reaction times and high yields. Boehmite nanoparticles was prepared, coated by silica and then reacted with chlorosulfuric acid to obtain Boehmite-SSA. This catalyst was characterized by FT-IR, TGA/DTA, XRD, TEM, SEM, EDS and BET techniques. BET curve of boehmite nanoparticles identified as a typical type IV isotherm (definition by IUPAC), which are the characteristics of mesoporous material. Nitrogen adsorption/desorption measurement indicated that boehmite nanoparticles had BET surface area of about 122.8?m2/g. The catalyst was easily separated and reused for the several runs without significant loss of its catalytic efficiency.
- Ghorbani-Choghamarani, Arash,Hajjami, Maryam,Tahmasbi, Bahman,Noori, Nourolah
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p. 2193 - 2202
(2016/11/06)
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- Sulfamic acid-functionalized nano-titanium dioxide as an efficient, mild and highly recyclable solid acid nanocatalyst for chemoselective oxidation of sulfides and thiols
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A highly efficient and retrievable titanium dioxide-based nanocatalyst has been synthesized by covalent grafting of chlorosulfonic acid on amine-functionalized titania as a novel inorganic-organic hybrid heterogeneous nanocatalyst, which was characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The acid strength of the catalyst was determined by pH analysis and the Hammett acidity function. The potential of the resultant nanocatalyst was effectively evaluated for the chemoselective oxidation of sulfides to sulfoxides and thiols to disulfides using 30% H2O2 as an oxidant at room temperature under solvent-free conditions, which led to high conversion rates and yields. Optimization of the reaction conditions was studied by central composite design (CCD), which is one of the most widely used response surface methodologies. The catalyst can be easily recycled up to 10 times without significant decrease in catalytic activity, which makes it a promising catalyst for practical and large-scale applications. This work is the first report that uses 2,4-toluene diisocyanate as a linker for immobilizing liquid acid on a support.
- Tabrizian, Elham,Amoozadeh, Ali,Rahmani, Salman
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p. 21854 - 21864
(2016/03/08)
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- Pd/Al2O3-catalysed redox isomerisation of allyl alcohol: Application in aldol condensation and oxidative heterocyclization reactions
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The application of the Pd/Al2O3 catalyst in allyl alcohol isomerization and subsequent aldol condensation and heterocyclization reactions is described. The activity of Pd/Al2O3 in these transformations is suggested to be due to the participation of the Lewis acidic sites of the support in the activation of the alcohol towards oxidative dehydrogenation by the metal and subsequent hydride transfer. The resulting enol(ate)/aldehyde could undergo further reactions promoted by the acid-base properties of the support. In the aldol condensation reactions of the isomerization product, electron poor aromatic aldehydes and heteroaromatic aldehydes showed the highest activity, while aromatic aldehydes bearing electron donating substituents reacted after transformation to the corresponding N-tosyl imines. 1,2-Disubstituted aromatics gave heterocyclic products in one-pot multistep reaction sequences.
- Zsolnai, Dániel,Mayer, Péter,Szori, Kornél,London, Gábor
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p. 3814 - 3820
(2016/06/13)
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- Iodine-catalyzed formation of substituted 2-aminobenzothiazole derivatives in PEG400
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An iodine-catalyzed formation of substituted 2-aminobenzothiazole derivatives is herein described using hydrogen peroxide as an oxidant in PEG400. The method enabled an efficient environmentally sound access to this valuable scaffold in moderate to excellent yields under metal-free conditions.
- Dumonteil,Hiebel,Scherrmann,Berteina-Raboin
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p. 73517 - 73521
(2016/08/19)
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- One-Pot Synthesis and Evaluation of Antileishmanial Activities of Functionalized S-Alkyl/Aryl Benzothiazole-2-carbothioate Scaffold
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The synthesis of hitherto unreported S-alkyl/aryl benzothiazole-2-carbothioate is reported from thiols, oxalyl chloride, and 2-aminothiophenols using 10 mol % n-tetrabutylammonium iodide (TBAI) as catalyst in acetonitrile through multicomponent reaction (MCR) strategy. The present protocol favored formation of benzothiazoles and thioesters via simultaneous formation of C-N and C-S bonds in good yields with a wide range of substrates. A few of the synthesized derivatives were evaluated for their antimicrobial activity against the protozoan parasite Leishmania donovani, a causative agent of visceral leishmaniasis (VL). Further, these compounds displayed no toxicity toward macrophage RAW 264.7 cells and are therefore nontoxic and effective antileishmanial leads. In silico docking studies were performed to understand the possible binding site interaction with trypanothione reductase (TryR).
- Dar, Ajaz A.,Shadab,Khan, Suman,Ali, Nahid,Khan, Abu T.
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p. 3149 - 3160
(2016/05/19)
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- Synthesis of 2-Arylbenzothiazoles by Copper-Catalyzed One-Pot Three-Component Reactions in Water
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Copper-catalyzed three-component reactions of 2-iodoanilines, benzylamines, and sulfur powder are reported to afford benzothiazoles in a simple one-pot procedure by using water as solvent. A variety of 2-arylbenzothiazoles were obtained in moderate to good yields up to 88%.
- Xu, Hualong,Luo, Chun,Li, Zhengkai,Xiang, Haifeng,Zhou, Xiangge
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p. 1207 - 1213
(2016/07/29)
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- Schiff base complexes of Ni, Co, Cr, Cd and Zn supported on magnetic nanoparticles: As efficient and recyclable catalysts for the oxidation of sulfides and oxidative coupling of thiols
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Abstract Oxidation of sulfides to sulfoxides and oxidative coupling of thiols into their corresponding disulfides were carried out using hydrogen peroxide (H2O2) as oxidizing agent in the presence of immobilized Ni, Co, Cr, Zn or Cd complexes on Fe3O4 magnetic nanoparticles (M-Salen-MNPs) as stable, heterogeneous, efficient and magnetically recoverable nanocatalysts under mild reaction conditions. These supported complexes were characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). A variety of aromatic and aliphatic sulfides and thiols with different functional groups were successfully oxidized with short reaction times in good to excellent yields. Recovery of the catalyst is easily achieved by magnetic decantation and reused for several consecutive runs without significant loss of its catalytic efficiency.
- Ghorbani-Choghamarani, Arash,Darvishnejad, Zahra,Tahmasbi, Bahman
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p. 223 - 231
(2015/08/03)
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- Nickel Schiff-base complexes immobilized on boehmite nanoparticles and their application in the oxidation of sulfides and oxidative coupling of thiols as novel and reusable nano organometal catalysts
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Boehmite nanoparticles were prepared by very simple and inexpensive procedure in water at room temperature using commercially available materials. Two Schiff-base complexes of nickel have been immobilized on the boehmite nanoparticles. These catalysts were characterized by FT-IR spectroscopy, TGA, XRD, BET, UV-DRS, TEM, SEM, EDS and ICP-OES techniques. These compounds were applied as catalysts for the oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides under mild reaction conditions at room temperature. These catalysts were recovered by simple filtration and reused several times without significant loss of their catalytic efficiency.
- Ghorbani-Choghamarani, Arash,Tahmasbi, Bahman,Arghand, Fatemeh,Faryadi, Sara
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p. 92174 - 92183
(2015/11/17)
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