- Full continuous flow synthesis process of fluorine-containing aromatic hydrocarbon compounds
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The invention provides a full continuous flow synthesis process of a fluorine-containing aromatic hydrocarbon compound, and belongs to the technical field of preparation of halogenated hydrocarbon carbocyclic organic compounds. Arylamine and hydrogen fluoride are pumped into a thermostat A and a thermostat B respectively and flow into a micro-channel reactor C for a salt forming reaction after constant temperature treatment, and a sulfuric acid solution of nitrosyl sulfuric acid is pumped into a thermostat D and flows into a micro-channel reactor E together with a salt forming product flowing out of the micro-channel reactor C for a diazotization reaction after constant temperature treatment. A product flows into a micro-channel reactor F to be subjected to a thermal decomposition reaction, is cooled by a cooler G and then enters a three-phase separator H to be continuously separated, nitrogen is discharged after being subjected to spraying deacidification, a fluorine-containing aromatic hydrocarbon crude product is subjected to continuous alkali washing, continuous drying and continuous rectification to obtain a fluorine-containing aromatic hydrocarbon finished product, and a hydrofluoric acid and sulfuric acid mixture is subjected to continuous distillation to obtain a product. The hydrogen fluoride and sulfuric acid are obtained. The full continuous flow synthesis process has the advantages of high reaction yield, excellent product quality, good production safety, less pollutant discharge and the like.
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Paragraph 0123-0136
(2021/04/07)
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- Preparation method of 3,5-dimethylfluorobenzene
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The invention provides a preparation method of 3, 5-dimethylfluorobenzene, which comprises the following steps: adding 3,5-dimethylaniline into anhydrous hydrogen fluoride to generate hydrogen fluoride salt of 3,5-dimethylaniline; then adding sodium nitri
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Paragraph 0041-0053
(2020/07/02)
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- Synthetic method for 1,5-bis(chloromethyl)-3-fluorobenzene
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The invention discloses a synthetic method for 1,5-bis(chloromethyl)-3-fluorobenzene, which belongs to the field of chemical synthesis. The synthetic method comprises the following steps: adding concentrated sulfuric acid and fuming nitric acid into 3,5-dimethylchlorobenzene and carrying out a reaction in an ice bath so as to obtain 3,5-dimethylnitrobenzene; then adding ethanol and palladium charcoal and introducing hydrogen so as to obtain 3,5-dimethylaniline; allowing 3,5-dimethylaniline and tetrafluoroboric acid to undergo an ice bath and adding a sodium nitrite solution drop by drop; carrying out filtering after completion of addition and drying obtained filter residue; and placing the filter residue in a flask for decomposition, adding water and petroleum ether and carrying out distillation so as to obtain 1,5-bis(chloromethyl)-3-fluorobenzene.
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Paragraph 0007
(2017/02/17)
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- FLUORINATION OF ARYL COMPOUNDS
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The invention provides compositions and methods of using the compositions in fluorinating aryl precursors containing a leaving group replaceable by a fluorine atom. The compositions include a metal ion source, a electrophilic fluorine source, a base, and a compound, which is an aryl precursor of the aryl fluoride, and which has a leaving group replaceable by the fluorine atom. Exemplary methods of the invention make use of such compositions and methods to prepare an aryl fluoride compound. In an exemplary embodiment, the electrophilic fluorine source is a source of 18F.
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Paragraph 00122
(2014/07/22)
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- Continuous flow reactor for Balz-Schiemann reaction: A new procedure for the preparation of aromatic fluorides
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A facile and highly efficient procedure for the preparation of aromatic fluorides by Balz-Schiemann reaction via two continuous flow reactors has been set up. The continuous diazotization reactor was run at about 25 °C with residence times of 10-20 s, and the continuous fluorodediazoniation reactor was performed with a residence time of 1 min in high yields. The reaction times can be greatly reduced by increasing temperature and thereby taking advantage of superior mass and heat transfer of a continuous flow system.
- Yu, Zhi-Qun,Lv, Yan-Wen,Yu, Chuan-Ming,Su, Wei-Ke
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p. 1261 - 1263
(2013/03/14)
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- Cu-catalyzed fluorination of diaryliodonium salts with KF
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A mild Cu-catalyzed nucleophilic fluorination of unsymmetrical diaryliodonium salts with KF is described. This protocol preferentially fluorinates the smaller aromatic ligand on iodine(III). The reaction exhibits a broad substrate scope and proceeds with high chemoselectivity and functional group tolerance. DFT calculations implicate a CuI/CuIII catalytic cycle.
- Ichiishi, Naoko,Canty, Allan J.,Yates, Brian F.,Sanford, Melanie S.
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supporting information
p. 5134 - 5137
(2013/10/22)
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- Copper-mediated fluorination of arylboronate esters. Identification of a Copper(III) fluoride complex
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A method for the direct conversion of arylboronate esters to aryl fluorides under mild conditions with readily available reagents is reported. Tandem reactions have also been developed for the fluorination of arenes and aryl bromides through arylboronate ester intermediates. Mechanistic studies suggest that this fluorination reaction occurs through facile oxidation of Cu(I) to Cu(III), followed by rate-limiting transmetalation of a bound arylboronate to Cu(III). Fast C-F reductive elimination is proposed to occur from an aryl-copper(III)-fluoride complex. Cu(III) intermediates have been generated independently and identified by NMR spectroscopy and ESI-MS.
- Fier, Patrick S.,Luo, Jingwei,Hartwig, John F.
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supporting information
p. 2552 - 2559
(2013/03/29)
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- Copper-mediated fluorination of aryl iodides
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The synthesis of aryl fluorides has been studied intensively because of the importance of aryl fluorides in pharmaceuticals, agrochemicals, and materials. The stability, reactivity, and biological properties of aryl fluorides can be distinct from those of the corresponding arenes. Methods for the synthesis of aryl fluorides, however, are limited. We report the conversion of a diverse set of aryl iodides to the corresponding aryl fluorides. This reaction occurs with a cationic copper reagent and silver fluoride. Preliminary results suggest this reaction is enabled by a facile reductive elimination from a cationic arylcopper(III) fluoride.
- Fier, Patrick S.,Hartwig, John F.
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supporting information; experimental part
p. 10795 - 10798
(2012/08/07)
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- FLUORINATION OF ORGANIC COMPOUNDS
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Methods for fluorinating organic compounds are described herein.
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Page/Page column 91
(2010/07/10)
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- Fluorination of boronic acids mediated by silver(I) Triflate
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A regiospecific Ag-mediated fluorination reaction of aryl- and alkenylboronic acids and esters Is reported. The fluorination reaction uses commercially available reagents, does not require the addition of exogenous ligands, and can be performed on a multigram scale. This report discloses the first practical reaction sequence from arylboronic acid to aryl fluorides.
- Furuya, Takeru,Ritter, Toblas
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supporting information; experimental part
p. 2860 - 2863
(2009/12/05)
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- π-face donor properties of N-heterocyclic carbenes in grubbs II complexes
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The electron-donating properties of eighteen N-heterocyclic carbenes (N,N′-bis(2,6-dimethylphenyl)imidazol)-2-ylidene and the respective dihydro ligands) with 4,4′-R substituted aryl rings (4,4′-R = NEt2, OMe, Me, H, SMe, F, Cl, Br, I) in the r
- Leuthaeusser, Steffen,Schmidts, Volker,Thiele, Christina M.,Plento, Herbert
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experimental part
p. 5465 - 5481
(2009/06/06)
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- Preparation process of fluorine substituted aromatic compound
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A preparation process of a fluorine substituted aromatic compound comprising reacting an alkali metal or alkali earth metal salt of an aromatic compound having a hydroxy group with an organic fluorinating agent is disclosed. As a representative fluorinating agent, a bis-dialkylamino-difluoromethane compound, for example, 2,2′-difluoro-1,3-dimethylimidazolidine, is exemplified. According to the process, an industrially useful fluorinated aromatic compound, for example, a fluorobenzene, a fluorine substituted benzophenone, a fluorine substituted diarylsulfone can be prepared with ease in economy without specific equipment.
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- The synthesis of [18F]fluoroarenes from the reaction of cyclotron-produced [18F]fluoride ion with diaryliodonium salts
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Diaryliodonium salts have been shown to react with fluoride ion at 80°C in acetonitrile to generate aryl fluorides. The regioselectivity is controlled electronically and by the bulk of the ortho-substituents on the rings, with the latter the dominant factor such that electron-rich rings can be fluorinated. ortho-Substituted aryl fluorides can be selectively produced from unsymmetrical diaryliodonium salts. The process has been used to synthesise [18F] labelled aromatics by the use of cyclotron generated [18F]fluoride ion.
- Shah, Aneela,Pike, Victor W.,Widdowson, David A.
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p. 2043 - 2046
(2007/10/03)
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- Reversible dioxygen binding and aromatic hydroxylation in O2-reactions with substituted xylyl dinuclear copper(I) complexes: Syntheses and low-temperature kinetic/thermodynamic and spectroscopic investigations of a copper monooxygenase model system
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The binding and subsequent reactivity of dioxygen (O2) upon binding to copper ion centers is of fundamental interest in chemical and biological processes. We provide here a detailed account of the reaction of O2 with dicopper(I) complexes, involving O2-reversible binding, followed by the stoichiometric aromatic hydroxylation of the ligand. Thus, tricoordinated dicopper(I) complexes [Cu2(R-XYL)]2+ (R = H, MeO, t-Bu, F, CN, NO2; 1a-f) possess dinucleating meta-substituted xylylene ligands with two chelating tridentate bis[2-(2-pyridyl)ethyl]amine (PY2) moieties and a 5-R substituent. Upon reaction with O2, dioxygen adducts [Cu2(R-XYL)(O2)]2+ (2a,c-f) form reversibly, and these subsequently yield 2-xylylene-hydroxylated products [Cu2(R-XYL-O-)(OH)]2+ (3a-f), which are phenoxo- and hydroxo-bridged copper(II) complexes. The products 3 have been characterized via the X-ray structure of the parent complex 3a, and by their UV-visible, infrared, and room-temperature magnetic properties. Incorporation of the O-atom from dioxygen into the phenolic products has been proven by isotopic labeling experiments, except in the case of 3f, where workup results in an exchange reaction causing loss of the oxygen label. In reactions of O2 with 1 in dichloromethane at room temperature, 10-25% yields of unhydroxylated complexes [Cu2(R-XYL)(OH)]3+ (5) are obtained. A stopped-flow kinetics study of O2 reactions of 1 in CH2Cl2 demonstrates that [Cu2(R-XYL)(O2)]2+ (2a,c-f) complexes form reversibly, proceeding via the reaction 1 + O2 ? 2 (K1 = k1/k-1); this is followed by the irreversible reaction 2 → 3 (k2). Analysis of temperature-dependent data which is accompanied by spectrophotometric monitoring yields both kinetic and thermodynamic parameters for R = H, t-Bu, F, and NO2. Dioxygen binding to 1 occurs in a single observable step with low activation enthalpies (6-29 kJ mol-1) and large, negative activation entropies (-66 to -167 J K-1 mol-1). The remote R-substituent has a significant effect on the dioxygen-binding process and this is explained in terms of its multistep nature. Strong binding (K1) occurs at low temperature (e.g. -80 °C), and thermodynamic parameters indicate a large enthalpic contribution (ΔH° = -52 to -74 kJ mol-1), but room-temperature stabilities of the dioxygen adducts are precluded by very large unfavorable entropies (ΔS° = -156 to -250 J K-1 mol-1). Electron-releasing R-substituents cause a small but significant enhancement of k2, the hydroxylation step, consistent with a mechanism involving electrophilic attack of the Cu2O2 intermediate 2 upon the xylyl aromatic ring. The influence of substituent upon the various rates of reaction allows for stabilization (~minutes), allowing the bench-top observation of 2d,e,f using UV-visible spectroscopy at -80 °C. "Vacuum-cycling" experiments can be carried out on 1f/2f, i.e., the repetitive oxygenation of 1f at -80 °C, followed by removal of O2 from 2f by application of a vacuum. Dicopper(I) complexes I have been characterized by 1H and 13C NMR spectroscopy, along with analogs in which an ethyl group has been placed in the 5-position of the pyridyl ring donor groups, i.e., [CuI2(R-XYL-(5-Et-PY))]2+ (1g, R = H; 1h, R = NO2). Variable-temperature 1H NMR spectroscopic studies provide clues as to why [Cu2(MeO-XYL)]2+ (1b) does not oxygenate (i.e., bind O2 and/or hydroxylate) at low temperature, the conclusion being that significant interactions of the coordinately unsaturated copper(I) ion(s) with the chelated methoxybenzene group result in conformations unsuitable for O2-reactivity. The biological implications of the biomimetic chemistry described here are discussed, as a system effecting oxidative C-H functionalization using O2 under mild conditions and as a monooxygenase model system for tyrosinase (phenol o-monooxygenase), with its dinuclear active site.
- Karlin, Kenneth D.,Nasir, M. Sarwar,Cohen, Brett I.,Cruse, Richard W.,Kaderli, Susan,Zuberbühler, Andreas D.
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p. 1324 - 1336
(2007/10/02)
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- A Mechanism for the Photosubstitution of Fluoro- and Methoxy-benzenes by Diethylamine
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The photochemical reactions of fluoro- and methoxy-benzenes with diethylamine produce addition and substitution products.The proposed mechanism involves quenching of the singlet state by the amine to give an exciplex.Proton transfer within the exciplex leads to the amine adducts, some of which can undergo elimination to yield the substitution products.
- Bunce, Nigel J.,Cater, Stephen R.
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p. 169 - 174
(2007/10/02)
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- Effect of Substituents at the 5-Position on the First and Second Dissociation Constants of Isophthalic Acid
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The dissociation constants of benzoic acid and 20 of its meta- or para-substituted derivatives and of isophthalic acid and ten of its 5-substituted derivatives have been measured in 50 wtpercent aqueous methanol.The Hammett ρ value for benzoic acid is 1.28; for isophthalic acid the ρ values are 1.21 (pK1) and 1.20 (pK2).The ?meta values for hydroxy and acetoxy are -0.01 and +0.29, respectively, in this system.Values for ?meta for CO2H and CO2- are calculated to be +0.28 and -0.20, respectively; however there are indications that these values are not completely structure-independent.
- Gumbley, Stewart J.,Stewart, Ross
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p. 529 - 532
(2007/10/02)
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