- Influence of Temperature on the Liquid-Liquid Equilibrium of the Ternary System Acetonitrile-2-Furyloxirane-Cyclohexane
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2-Furyloxirane can be obtained by a low hydrated solid-liquid phase transfer process from furfural and a sulfonium salt in basic medium by using acetonitrile as a solvent.It is purified by extraction in a reactive medium with an extracting solvent, cyclohexane.Diagrams on solubility isotherms and tie-line data are given for the ternary system acetonitrile-2-furyloxirane-cyclohexane at 20-30 and 40 deg C.Under these conditions 2-furyloxirane extraction by cyclohexane appears not to depend on temperature.
- Rakotondramanana, Samuel,Borredon, Marie-Elisabeth,Molinier, Jacques
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- Trimethylsulfonium bromide
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The reaction of dimethyl sulfoxide and ethyl bromoacetate at room temperature gives the title compound (CH3)3S.Br, which consists of layers of pyramidal trimethylsulfonium ions and bromide ions.
- Svensson, Per H.,Kloo, Lars
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- Redox-Divergent Construction of (Dihydro)thiophenes with DMSO
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Thiophene-based rings are one of the most widely used building blocks for the synthesis of sulfur-containing molecules. Inspired by the redox diversity of these features in nature, we demonstrate herein a redox-divergent construction of dihydrothiophenes, thiophenes, and bromothiophenes from the respective readily available allylic alcohols, dimethyl sulfoxide (DMSO), and HBr. The redox-divergent selectivity could be manipulated mainly by controlling the dosage of DMSO and HBr. Mechanistic studies suggest that DMSO simultaneously acts as an oxidant and a sulfur donor. The synthetic potentials of the products as platform molecules were also demonstrated by various derivatizations, including the preparation of bioactive and functional molecules.
- Chen, Qing-An,He, Gu-Cheng,Hu, Yan-Cheng,Ji, Ding-Wei,Liu, Heng,Zhang, Xiang-Xin,Zhao, Chao-Yang
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supporting information
p. 24284 - 24291
(2021/10/08)
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- Synthesis, characterization and optoelectronic properties of chemically stable (CH3)3SPbI3?xBrx and (CH3)3SPbI3?xClx (x?=?0, 1, 2, 3) perovskites
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We report on the novel series of (CH3)3SPbI3?xBrx and (CH3)3SPbI3?xClx (x = 0, 1, 2, 3) perovskite compounds. X-ray diffraction analysis shows that the solid solutions of (CH3)3SPbI3?xBrx (x = 0, 1, 2, 3) and (CH3)3SPbI3?xClx (x = 0, 1, 2) crystallize in hexagonal symmetry (space group P63mc, No. 186) with 1D columns of face-sharing [PbX6] octahedra. (CH3)3SPbCl3 crystallizes in orthorhombic symmetry (space group Pnma, No. 62) forming 3D network of vertex- and face-sharing [PbCl6] octahedra. Optical and vibrational properties were investigated using UV–vis reflectance, photoluminescence and Raman spectroscopy at room temperature. The compounds show high chemical stability in ambient air at temperatures up to 80 °C and under solar simulator, in contrast to the hygroscopic CH3NH3PbI3 or CH(NH2)2PbI3 that are commonly used in perovskite solar cells. First principles theoretical ab initio and efficient semiempirical extended Hückel calculations were performed to evaluate the energy band gap values, whose results are in good agreement with the experimentally determined values.
- Kaltzoglou, Andreas,Elsenety, Mohamed M.,Koutselas, Ioannis,Kontos, Athanassios G.,Papadopoulos, Kyriakos,Psycharis, Vassilis,Raptopoulou, Catherine P.,Perganti, Dorothea,Stergiopoulos, Thomas,Falaras, Polycarpos
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- Preparation method of medetomidine and intermediate thereof
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The invention relates to a preparation method of 2-(2, 3-xylyl)-2-methyloxirane. The method is characterized in that the preparation process includes the following reaction shown as the specification, wherein Y is selected from Cl, Br, I, CH3SO4 or HSO4; alkali is selected from KOH, NaOH, LiOH, CsOH, K2CO3, Li2CO3, Cs2CO3, Na2CO3, EtONa, EtOK, (CH3)2CHONa, (CH3)2CHOK, (CH3)3CONa, (CH3)3COK, NH2Na or NH2K. The invention adopts the synthesis method using the 2-(2, 3-xylyl)-2-methyloxirane critical intermediate to prepare medetomidine.
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Paragraph 0072; 0073; 0074; 0075
(2017/08/28)
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- Method to prepare trimethylsulfonium halides
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Trimethylsulfonium halides are made by reacting dimethyl sulfide and a methyl halide in the presence of a solvent mixture which includes water and a water-immiscible organic solvent. The organic water-immiscible solvent is generally present in an amount which is at least 40% but no more than 95% of the total solvent mixture. The reaction is preferably conducted under pressure.
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- Preparation of oxiranes
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A process for the preparation of an oxirane of the formula STR1 in which Y is chlorine or phenyl, X is oxygen or CH2, and Z is hydrogen or halogen, comprising reacting dimethyl sulphide with methyl bromide in the presence of an inert organic diluent thereby to produce trimethylsulphonium bromide of the formula and reacting the trimethylsulphonium bromide with a ketone of the formula STR2 in the presence of a base and in the presence of an inert organic diluent, at a temperature between about 0° C. and 60° C. The end products are produced in high yield and are known intermediates for known fungicides.
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- Method to prepare trimethylsulfonium halides
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Trimethylsulfonium halides are made by reacting dimethyl sulfide and a methyl halide in the presence of water. The reaction is preferably conducted under pressure.
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- EPOXYDATION EM MILIEU HETEROGENE SOLIDE-LIQUIDE FAIBLEMENT HYDRATE : ETUDE DE LA REACTION AUTOUR DE LA STRUCTURE DU SEL DE SULFONIUM
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Epoxide formation by sulphur ylid insertion into aldehydes under heterogeneous conditions in the presence of small quantities of water is described.Trimethylsulphonium and S-methylthiolanium bromide and iodide have been studied.For all alkyl substituents the bromide gives better results than the iodide, this is interpreted in terms of the reaction mechanisms.Under optimum conditions high yields of epoxides are obtained.
- Borredon, M.E.,Delmas, M.,Gaset, A.
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p. 3945 - 3954
(2007/10/02)
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- Bromonitromethane. A Versatile Electrophile
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Pathways in reactions of bromonitromethane with a variety of nucleophiles have been investigated.With thiolates, the electrophilic centre is bromine and the initial products are disulphides.When the thiolate ion itself carries an electrophilic centre such as carbonyl or cyano β-to sulphur, the product is a nitrothiophene derived from subsequent reaction of the first-formed disulphide with nitronate ion displaced in the initial process.This provides a generalisation of earlier nitrothiophene synthesis by this route.In reactions with arenesulphinate ion, the electrophilic centre is also bromine and equilibration between the initial reactants and the initial products, sulphonyl bromide and nitronate ion, is established.The components of the equilibrium subsequently react either with each other or with the solvent.Reactions with sulphides are slow and distal substituents such as hydroxy- or cyano- so much reduce reactivity that no reaction is observed.Dimethyl sulfide attacks bromonitromethane at the carbon atom,and subsequent attack on the nitromethyl sulphonium salt initially formed gives methylthionitromethane and trimethylsulphonium bromide.Iodide ion attacks at bromine to give iodine, presumably via iodine bromide, but with tervalent phosphorus nucleophiles, attack is at oxygen giving the corresponding oxides and HCN in a double deoxygenation sequence.For hydroxide, methoxide and hydride ions (from sodium borohydride), nucleophilic attack is at hydrogen and the nitronate ion produced is inert to further attack.There is no evidence of carbene formation by α-elimination.When the anion of bromonitromethane is allowed to react with tributylboron, the anionic migration-displacement which follows boron-carbon bond formation, yields 1-nitropentane.The anion of bromonitromethane is unreactive towards aldehydes and electrophilic alkenes.
- Fishwick, Brian R.,Rowles, David K.,Stirling, Charles J. M.
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p. 1171 - 1180
(2007/10/02)
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- Bromonitromethane, a Versatile Electrophile: Reactions with Feebly Basic Nucleophiles
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Bromonitromethane reacts with feebly basic sulphur, phosphorus, and halogen nucleophiles at bromine or at carbon; the anion of bromonitromethane reacts with tributylboron to give 1-nitropentane.
- Fishwick, Brian R.,Rowles, David K.,Stirling, Charles J. M.
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p. 835 - 836
(2007/10/02)
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