139-02-6Relevant articles and documents
Mononuclear Sulfido-Tungsten(V) Complexes: Completing the Tp*MEXY (M = Mo, W; E = O, S) Series
Sproules, Stephen,Eagle, Aston A.,George, Graham N.,White, Jonathan M.,Young, Charles G.
, p. 5189 - 5202 (2017)
Orange Tp*WSCl2 has been synthesized from the reactions of Tp*WOCl2 with boron sulfide in refluxing toluene or Tp*WS2Cl with PPh3 in dichloromethane at room temperature. Mononuclear sulfido-tungsten(V) complexes, Tp*WSXY {X = Y = Cl, OPh, SPh, SePh; X = Cl, Y = OPh; XY = toluene-3,4-dithiolate (tdt), quinoxaline-2,3-dithiolate (qdt); and Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate} were prepared by metathesis of Tp*WSCl2 with the respective alkali metal salt of X-/XY2-, or [NHEt3]2(qdt). The complexes were characterized by microanalysis, mass spectrometry, electrochemistry, and infrared (IR), electron paramagnetic resonance (EPR) and electronic absorption spectroscopies. The molecular structures of Tp*WS(OPh)2, Tp*WS(SePh)2, and Tp*WS(tdt) have been determined by X-ray crystallography. The six-coordinate, distorted-octahedral W centers are coordinated by terminal sulfido (WS = 2.128(2) - 2.161(1) ?), terdentate facial Tp*, and monodentate/bidentate O/S/Se-donor ligands. The sulfido-W(V) complexes are characterized by lower energy electronic transitions, smaller giso, and larger Aiso(183W) values, and more positive reduction potentials compared with their oxo-W(V) counterparts. This series has been probed by sulfur K-edge X-ray absorption spectroscopy (XAS), the spectra being assigned by comparison to Tp*WOXY (X = Y = SPh; XY = tdt, qdt) and time-dependent density functional theoretical (TD-DFT) calculations. This study provides insight into the electronic nature and chemistry of the catalytically and biologically important sulfido-W unit.
Structure and reactivity of sodium phenoxide - Following the course of the Kolbe-Schmitt reaction
Kunert, Michael,Dinjus, Eckhard,Nauck, Maria,Sieler, Joachim
, p. 1461 - 1465 (1997)
Solvent-free sodium phenoxide (NaOPh) crystallises as a polymer and forms a polymeric chain in the [001] direction. The low coordination of the sodium atoms, as evident in the crystal structure, is confirmed by the easy coordination of oxoligands (σ-donors). Hence, the four-membered ring chain of the solvent-free sodium phenoxide is separated by oxoligands, and forms partial structures as the polymer fragments. Thus, NaOPh crystallises in THF with the formation of an Na6O6 core, consisting of two face-fused heterocubes, and in N,N,N′,N′-tetrarnethyl urea (TMU) with the formation of a Na4O4 heterocubane. The solvent-free NaOPh-CO2 complex obtained from the addition of CO2 to a solution of sodium phenoxide is, when exposed to a temperature of 80 °C, subject to an irreversible phase transition, as demonstrated by FT-IR and DTA studies. The complex formed at 80 °C is, apparently, another intermediate of the Kolbe-Schmitt reaction. WILEY-VCH Verlag GmbH,.
A New Antagonist of Caenorhabditis elegans Glutamate-Activated Chloride Channels With Anthelmintic Activity
Bouzat, Cecilia,Castro, María Julia,Faraoni, María Belén,Gerbino, Darío,Turani, Ornella
, (2020)
Nematode parasitosis causes significant mortality and morbidity in humans and considerable losses in livestock and domestic animals. The acquisition of resistance to current anthelmintic drugs has prompted the search for new compounds for which the free-living nematode Caenorhabditis elegans has emerged as a valuable platform. We have previously synthetized a small library of oxygenated tricyclic compounds and determined that dibenzo[b,e]oxepin-11(6H)-one (doxepinone) inhibits C. elegans motility. Because doxepinone shows potential anthelmintic activity, we explored its behavioral effects and deciphered its target site and mechanism of action on C. elegans. Doxepinone reduces swimming rate, induces paralysis, and decreases the rate of pharyngeal pumping required for feeding, indicating a marked anthelmintic activity. To identify the main drug targets, we performed an in vivo screening of selected strains carrying mutations in Cys-loop receptors involved in worm locomotion for determining resistance to doxepinone effects. A mutant strain that lacks subunit genes of the invertebrate glutamate-gated chloride channels (GluCl), which are targets of the widely used antiparasitic ivermectin (IVM), is resistant to doxepinone effects. To unravel the molecular mechanism, we measured whole-cell currents from GluClα1/β receptors expressed in mammalian cells. Glutamate elicits macroscopic currents whereas no responses are elicited by doxepinone, indicating that it is not an agonist of GluCls. Preincubation of the cell with doxepinone produces a statistically significant decrease of the decay time constant and net charge of glutamate-elicited currents, indicating that it inhibits GluCls, which contrasts to IVM molecular actions. Thus, we identify doxepinone as an attractive scaffold with promising anthelmintic activity and propose the inhibition of GluCls as a potential anthelmintic mechanism of action.
Electrochemical reductive dehalogenation of ortho-halogenated phenols on Ag electrode by in situ FTIR
Yi, Jingmiao,Lu, Jinjin,Shi, Xiaohong,Song, Dandan,Zhao, Weijuan,Li, Meichao
, p. 3879 - 3882 (2014)
Electrochemical reductive dehalogenation reactions of ortho-halogenated phenols, namely, o-iodophenol (OIP), o-bromphenol (OBP) and o-chlorophenol (OCP) on Ag electrode in alkaline medium have been studied by in situ FTIR combined with cyclic voltammetry and computational calculations. The Ag electrode showed a high electrochemical activity for dehalogenation reactions of OBP and OIP in contrast with OCP under the similar conditions and the dehalogenation potential of OIP was more positive than OBP, reflecting more facile reduction of OIP on Ag electrode. On the basis of in situ FTIR of OCP on Ag electrode, it was not obvious and the electrochemical reduction reaction was quite weak. Therefore, the order of electrochemical reductive dehalogenation was OIP > OBP > OCP.
Synthetic method of methyl salicylate
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Paragraph 0016; 0020; 0024, (2021/02/10)
The invention discloses a synthesis method of methyl salicylate. The method comprises the following steps: preparing sodium phenolate by using caustic soda flakes and phenol as raw materials, carryingout carboxylation reaction on the obtained sodium phenolate and carbon dioxide gas to obtain sodium salicylate, reacting the obtained sodium salicylate with chloromethane gas under the action of a phase transfer catalyst to obtain a crude methyl salicylate product containing a toluene solvent, neutralizing and washing the crude methyl salicylate product, recovering the toluene solvent at normal pressure, and carrying out vacuum distillation to obtain a finished methyl salicylate product. According to the method, a strong acid catalyst is not used, so that the wastewater amount is greatly reduced, and the corrosion to equipment and the pollution to the environment are reduced. According to the method, equipment is not seriously corroded, the wastewater amount is small, and the process is more environmentally friendly.
NHC-CDI Betaine Adducts and Their Cationic Derivatives as Catalyst Precursors for Dichloromethane Valorization
Sánchez-Roa, David,Mosquera, Marta E. G.,Cámpora, Juan
, p. 16725 - 16735 (2021/11/18)
Zwitterionic adducts of N-heterocyclic carbene and carbodiimide (NHC-CDI) are an emerging class of organic compounds with promising properties for applications in various fields. Herein, we report the use of the ICyCDI(p-Tol) betaine adduct (1a) and its cationic derivatives2aand3aas catalyst precursors for the dichloromethane valorization via transformation into high added value products CH2Z2(Z = OR, SR or NR2). This process implies selective chloride substitution of dichloromethane by a range of nucleophiles Na+Z-(preformed or generatedin situfrom HZ and an inorganic base) to yield formaldehyde-derived acetals, dithioacetals, or aminals with full selectivity. The reactions are conducted in a multigram-scale under very mild conditions, using dichloromethane both as a reagent and solvent, and very low catalyst loading (0.01 mol %). The CH2Z2derivatives were isolated in quantitative yields after filtration and evaporation, which facilitates recycling the dichloromethane excess. Mechanistic studies for the synthesis of methylal CH2(OMe)2rule out organocatalysis as being responsible for the CH2transfer, and a phase-transfer catalysis mechanism is proposed instead. Furthermore, we observed that1aand2areact with NaOMe to form unusual isoureate ethers, which are the actual phase-transfer catalysts, with a strong preference for sodium over other alkali metal nucleophiles.
Dehydrogenative Coupling of Aldehydes with Alcohols Catalyzed by a Nickel Hydride Complex
Eberhardt, Nathan A.,Wellala, Nadeesha P. N.,Li, Yingze,Krause, Jeanette A.,Guan, Hairong
, p. 1468 - 1478 (2019/04/17)
A nickel hydride complex, {2,6-(iPr2PO)2C6H3}NiH, has been shown to catalyze the coupling of RCHO and R′OH to yield RCO2R′ and RCH2OH, where the aldehyde also acts as a hydrogen acceptor and the alcohol also serves as the solvent. Functional groups tolerated by this catalytic system include CF3, NO2, Cl, Br, NHCOMe, and NMe2, whereas phenol-containing compounds are not viable substrates or solvents. The dehydrogenative coupling reaction can alternatively be catalyzed by an air-stable nickel chloride complex, {2,6-(iPr2PO)2C6H3}NiCl, in conjunction with NaOMe. Acids in unpurified aldehydes react with the hydride to form nickel carboxylate complexes, which are catalytically inactive. Water, if present in a significant quantity, decreases the catalytic efficiency by forming {2,6-(iPr2PO)2C6H3}NiOH, which causes catalyst degradation. On the other hand, in the presence of a drying agent, {2,6-(iPr2PO)2C6H3}NiOH generated in situ from {2,6-(iPr2PO)2C6H3}NiCl and NaOH can be converted to an alkoxide species, becoming catalytically competent. The proposed catalytic mechanism features aldehyde insertion into the nickel hydride as well as into a nickel alkoxide intermediate, both of which have been experimentally observed. Several mechanistically relevant nickel species including {2,6-(iPr2PO)2C6H3}NiOC(O)Ph, {2,6-(iPr2PO)2C6H3}NiOPh, and {2,6-(iPr2PO)2C6H3}NiOPh·HOPh have been independently synthesized, crystallographically characterized, and tested for the catalytic reaction. While phenol-containing molecules cannot be used as substrates or solvents, both {2,6-(iPr2PO)2C6H3}NiOPh and {2,6-(iPr2PO)2C6H3}NiOPh·HOPh are efficient in catalyzing the dehydrogenative coupling of PhCHO with EtOH.
Reversible Hydrogen Uptake/Release over a Sodium Phenoxide–Cyclohexanolate Pair
Yu, Yang,He, Teng,Wu, Anan,Pei, Qijun,Karkamkar, Abhijeet,Autrey, Tom,Chen, Ping
, p. 3102 - 3107 (2019/01/04)
Hydrogen uptake and release in arene–cycloalkane pairs provide an attractive opportunity for on-board and off-board hydrogen storage. However, the efficiency of arene–cycloalkane pairs currently is limited by unfavorable thermodynamics for hydrogen release. It is shown here that the thermodynamics can be optimized by replacement of H in the -OH group of cyclohexanol and phenol with alkali or alkaline earth metals. The enthalpy change upon dehydrogenation decreases substantially, which correlates with the delocalization of the oxygen electron to the benzene ring in phenoxides. Theoretical calculations reveal that replacement of H with a metal leads to a reduction of the HOMO–LUMO energy gap and elongation of the C?H bond in the α site in cyclohexanolate, which indicates that the cyclohexanol is activated upon metal substitution. The experimental results demonstrate that sodium phenoxide–cyclohexanolate, an air- and water-stable pair, can desorb hydrogen at ca. 413 K and 373 K in the solid form and in an aqueous solution, respectively. Hydrogenation, on the other hand, is accomplished at temperatures as low as 303 K.
Catalytic, antibacterial and antibiofilm efficacy of biosynthesised silver nanoparticles using Prosopis juliflora leaf extract along with their wound healing potential
Arya, Geeta,Kumari, R. Mankamna,Sharma, Nikita,Gupta, Nidhi,Kumar, Ajeet,Chatterjee, Sreemoyee,Nimesh, Surendra
, p. 50 - 58 (2018/11/26)
The present study focuses on the catalytic, antibacterial and antibiofilm efficacy of silver nanoparticles (AgNPs) in an easy, rapid and eco-friendly pathway. Herein, we have synthesised AgNPs using an aqueous extract of P. juliflora leaf. The bioactive compounds present in the extract are responsible for the reduction of Ag+ to Ag0. The particle synthesis was first observed by visual color change and then characterized using UV–visible spectroscopy to confirm the formation of AgNPs. The synthesis conditions were then optimised using critical parameters such as reaction time, AgNO3 concentration, extract to AgNO3 ratio and temperature of the reaction. The hydrodynamic size of the AgNPs with Dynamic light scattering (DLS) was 55.24 nm, while, was in the range of 10–20 nm as determined through Transmission Electron Microscopy (TEM). Further, Fourier transform infrared spectroscopy (FTIR) studies were conducted to discern the functional groups or compounds responsible for the reduction of silver nitrate as well as the capping of silver nanoparticles. Later, X-ray diffraction (XRD) results showed crystalline nature of the biosynthesized AgNPs. To evaluate their antibacterial potential, AgNPs were assessed through disc-diffusion assay, which resulted in an appreciable dose-dependent activity. The antibacterial potential was investigated through disc-diffusion assay against E. coli and P. aeruginosa. The Congo red agar (CRA) plate assay successfully revealed the anti-biofilm activity against B. subtilis and P. aeruginosa. Further, the catalytic activity of synthesised AgNPs was assessed against azo dyes such a Methylene Blue (MB) and Congo Red (CR) that resulted in its effective degradation of toxic compounds in a short span of time. Further, AgNPs were assessed for their wound healing potential.
A benzene oxygen suo ester preparation method (by machine translation)
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Paragraph 0047; 0048; 0049; 0050; 0051; 0052; 0053-0058, (2019/01/08)
The present invention provides a benzene oxygen suo ester preparation method, comprises the following steps: A) phenol compounds and alkaline hydroxide in dehydrating in organic solvent to form the salt, the salt of the phenol compound obtained; B) into the salt, adding chlorine suo ester, a condensation reaction, to obtain benzene oxygen suo ester and mixed solution of [...]; C) to 1 - 5 °C/min speed will be the system temperature dropped to 37 - 42 °C, and ultrasonic, chloride salt crystal grain becomes large, filtering to remove the [...]; the organic solvent is toluene, xylene, chlorobenzene, phenol, butanol and isobutanol in any mixture of the two. The invention in a mixed organic solvent in the dewatering of the phenol salt, in the dehydration process system always maintain a state are, to realize the continuous production, and the dewatering efficiency is high, the whole production process efficiency is high. And raw materials are easy, production cycle is short, low energy consumption, low production cost. And filtering to generate of [...], realizes the zero to produce zero emission of waste water. (by machine translation)
