- Tetra-cmpo-derivatives of calix[4]arenes fixed in the 1,3-alternate conformation
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Calix[4]arene derivatives fixed in the 1,3-alternate conformation and substituted at one side by four carbamoylmethyl-phosphine oxide (CMPO) residues were synthesised. Two CMPO groups are directly attached to the wide rim, while the second pair is bound to the narrow rim via a tri- or tetramethylene spacer. Similar compounds, in which two CMPO groups at the wide rim are combined with two picolinamide groups or two ionisable carboxylic groups at the narrow rim, were also prepared. Some of these calixarene derivatives were studied as extractants for lanthanides (La3+,Eu3+,Yb3+) and thorium (Th4+) from acidic solution into methylene chloride. For selected samples, stability constants in methanol were determined by spectrophotometric titrations. Three compounds (1b′, 13, 17) in the 1,3-alternate conformation and one intermediate in the cone conformation (18) were confirmed by a crystal structure.
- Dordea, Crenguta,Brisach, Frederic,Haddaoui, Jaouad,Arnaud-Neu, Francoise,Bolte, Michael,Casnati, Alessandro,Boehmer, Volker
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Read Online
- Reactions of polyfluorinated 3-substituted 2,4-cyclohexadienones with alkynes
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Reactions of 2,3,4,5,6-pentafluoro-6-chloro-2,4-cyclohexadienone with anthranylic acid, 2,6-dichloro- and 2,6-dimethylaniline, diethylamine, sodium azide, and also the reaction of 6-phenyl-3-pentafluorophenoxy-2,4,5,6-tetrafluoro-2,4-cyclohexadienone with methanol afford 3-substituted 2,4,5,6-tetrafluoro-2,4-cyclohexadienones. The 3-methoxy-2,4,5,6-tetrafluoro-6-chloro-2,4-cyclohexadienone and 3-methoxy-6-phenyl-2,4,5,6-tetrafluoro-2,4-cyclohexadienone form cycloadducts with 1-hexyne and propargyl alcohol that under treatment with propyl alcohol in the presence of potassium carbonate undergo ring cleavage to furnish propyl arylfluorochloroacetates and diarylacetates. The reaction between 3-azido-2,4,5,6-tetrafluoro-6-chloro-2,4-cyclohexadienone and phenylacetylene gives rise to 4-oxo-2-phenyl-3,5,6,7-tetrafluoro-5-chlorobicyclo[4.1.0] hept-2-ene-7-carbonitrile.
- Kovtonyuk,Kobrina
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Read Online
- Self anion radical induced breaking carbon–oxygen bond in bay area of perylene diimide, and nucleophilic substitution with SRN1 mechanism
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Perylene diimide and its various derivatives tend to form their anion radicals after obtaining one electron, which will alter their chemical properties. Herein, we reported firstly synthesis of the unsymmetrically substituted perylene diimide in bay area
- Guo, Zhun,He, Zemin,Miao, Zongcheng,Zhang, Haiquan,Zhang, Huimin,Zhao, Yang,Zhao, Yuzhen
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supporting information
(2022/02/09)
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- Method for continuously preparing pentafluorophenol by micro-reactor
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The invention relates to a method for continuously preparing pentafluorophenol by a microreactor, which belongs to the field of chemical production processes. The method comprises the following steps:simultaneously pumping hexafluorobenzene and an inorganic alkali aqueous solution into a micro-channel reactor by using a metering pump respectively, and mixing for a hydrolysis reaction; keeping thetemperature of the reactor at 130-170 DEG C, controlling and maintaining the pressure of a pipeline at 0.5-1.0 Mpa by an outlet quantitative pressure control valve, connecting an outlet with a heat exchanger, obtaining an aqueous solution of pentafluorophenolate from the outlet of the heat exchanger, adding hydrochloric acid steam, distilling to obtain an oil layer, and rectifying and dehydratingthe oil layer to obtain pentafluorophenol. The method is simple in process, low in cost, free of amplification effect and capable of achieving continuous production.
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Paragraph 0027-0038
(2020/05/16)
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- Method for industrially producing pentafluorophenol
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The invention discloses a method for industrially producing pentafluorophenol. According to the invention, pentafluorobenzene is used as a raw material and the method comprises the following steps: grabbing benzene ring hydrogen in an organic solvent by using a solid super-strong alkali reagent, adding hydrogen peroxide for a reaction to obtain a desired product pentafluorophenol. The method has the advantages of simple process, realization of the separation yield reaching 94% or above (based on pentafluorobenzene), realization of the product content being greater than 99.2%, great reduction of the synthesis cost, and suitableness for industrial large-scale production. According to the method, solid super alkali is adopted to replace conventional inorganic alkali, corrosion of a conventional inorganic alkali solution to equipment is avoided, the requirement for equipment materials is lowered, products are easy to separate, operation is easy and convenient, and industrial production isfacilitated.
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Paragraph 0044-0047
(2020/07/28)
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- Preparation method of pentafluorophenol
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The invention relates to the field of organic synthesis, in particular to a preparation method of pentafluorophenol. The preparation method of pentafluorophenol comprises the steps as follows: 1) pentafluorobenzonitrile and bromoacetic ester are subjected to a coupling reaction in the presence of zinc powder, hydrolysis and decarboxylation are performed under the acid condition, and pentafluoroacetophenone is prepared; 2) pentafluoroacetophenone is subjected to a Baeyer-Villiger reaction in the presence of an oxidizing agent, and pentafluorophenol is prepared after hydrolysis. The preparationmethod of pentafluorophenol comprises simple and short operation steps and is low in production cost, high in industrial operability and suitable for large-scale industrial production.
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Paragraph 0071; 0073
(2020/07/24)
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- Preparation method of pentafluorophenol
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The invention relates to a preparation method of pentafluorophenol, and belongs to the field of chemical production technologiesprocesses. The preparation method of the pentafluorophenol is carried out according to the following technologies processes that hexafluorobenzene, strong base and water are put in a sealed container, to be prepared intothus a mixed solution is prepared, heat preservationis conducted at the temperature of 100-150 DEG C for reaction, and thus a system solution is obtained; the system solution is neutralized until the pH value is not higher than 6, then a coarse product is extracted, rectification is conducted, and the pentafluorophenol is obtained. According to the preparation method, the cost is low, organic matter and heavy metal are not adopted except for substrate, pollution is small, side reactions is are lessfewer, the reaction steps are simple, and operation is easy.
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Paragraph 0024-0025; 0026-0027; 0028-0029; 0030-0031
(2019/03/08)
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- Additive-free cobalt-catalysed hydrogenation of carbonates to methanol and alcohols
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Reduction of various organic carbonates to methanol and alcohols can be achieved in the presence of a molecularly-defined homogeneous cobalt catalyst. Specifically, the use of Co(BF4)2 in combination with either commercial or tailor-made tridentate phosphine ligands allows for additive-free hydrogenations of carbonates. Optimal results are obtained at relatively mild conditions (120 °C, 50 bar hydrogen pressure) in the presence of xylyl-Triphos L4.
- Ferretti, Francesco,Scharnagl, Florian Korbinian,Dall'Anese, Anna,Jackstell, Ralf,Dastgir, Sarim,Beller, Matthias
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p. 3548 - 3553
(2019/07/10)
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- Pentafluorophenol preparation mehtod
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The invention provides a pentafluorophenol preparation method. The pentafluorophenol preparation method is characterized by comprising the following preparation steps: adding 500-1000 parts of water, 50-100 parts of sodium hydroxide, 3-10 parts of a hydrolysis catalyst, 100 parts of hexafluorobenzene and 0.1-1 part of dodecyl secondary amine into a high pressure kettle according to parts by weight, sealing the high pressure kettle, raising the temperature to 110-150 DEG C, reacting for 3-8 hours, cooling to the room temperature, filtering, acidizing, extracting with methyl tert-butyl ether, combining an organic phase, distilling to recycle a solvent, and obtaining a crude product of 2,3,4,5,6-pentafluorophenol, adsorbing the crude product of pentafluorophenol in a crude product tank through five rectifying columns, and obtaining a purified product of pentafluorophenol.
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Paragraph 0013; 0014; 0016; 0017; 0024
(2017/09/01)
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- Pentafluorophenol preparation method
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The invention provides a pentafluorophenol preparation method, which comprises: using hexafluorobenzene and potassium hydroxide as raw materials, adding an appropriate amount of tetrabutylammonium hydrogen sulfate, N-sulfopropyl-3-methylpyridine triflate, N-methyl-2-[(2-methylphenoxy)acetyl]hydrazinium methylthioamide and 2,2,6,6-tetramethylpiperidine-oxynitride to a tert-butyl alcohol aqueous solution with a mass fraction of 80-85%, heating to achieve a slight boiling state, carrying out a reflux reaction for 2-3 h, adding an appropriate amount of water, distilling to recover the tert-butyl alcohol solvent, adjusting the PH value of the remaining aqueous solution by using refined hydrochloric acid to 9-10, adsorbing with a functionalized D101 macroporous adsorption resin, acidifying with refined hydrochloric acid to achieve the PH value of 1-2, layering, distilling the upper layer water phase until no oily substance exists, collecting the distilled product, combining the collected product and the lower layer oil phase, rectifying, collecting the distillate at the temperature of 142-144 DEG C, and cooling to a room temperature to obtain the colorless and transparent crystal pentafluorophenol. According to the present invention, the preparation method has advantages of simple and reasonable process, less side reactions, high reaction yield and high product purity, and can meet the quality requirements for the preparation of the high-quality liquid crystal materials and drugs.
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Paragraph 0013; 0014; 0015; 0016; 0017; 0018-0022
(2017/12/09)
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- A five-fluoro phenol preparation method
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The invention relates to a preparation method for pentafluorophenol. By taking hexafluorobenzene as an initial raw material, pentafluorophenol is prepared through etherification reaction and cracking reaction or by taking hexafluorobenzene as the initial raw material, pentafluorophenol is prepared by virtue of a one-step method. The preparation method provided by the invention does not need high temperature and pressurization, is less in energy consumption, and does not use expensive hydroiodic acid, so that the cost of the raw materials is low. Moreover, wastewater generated by etherification reaction is less, so that the preparation method is environmental-friendly; Cracking is carried out in a solvent, the material stirring effect is good, the reaction temperature is easy to control, and industrialization is easy to implement.
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Paragraph 0099; 0100; 0101; 0102
(2018/03/24)
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- Heteroleptic μ-nitrido diiron complex supported by phthalocyanine and octapropylporphyrazine ligands: Formation of oxo species and their reactivity with fluorinated compounds
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The synthesis and reactivity of N-bridged diiron macrocyclic complexes have been a topic of increasing interest in recent years since the observation of particular catalytic properties of these complexes. Herein, we report a preparation of a novel heteroleptic μ-nitrido diiron complex with unsubstituted phthalocyanine and octapropylporphyrazine macrocycles. This complex reacts with m-chloroperbenzoic acid to form high-valent diiron oxo species showing strong oxidizing properties. The formation and structure of the transient oxo species was investigated by cryospray collision induced dissociation MS/MS technique. Analysis of fragmentation pattern showed that the attachment of oxo moiety occurred at either iron phthalocyanine or at iron porphyrazine site with slight preference for the phthalocyanine iron site. The catalytic properties of the heteroleptic μ-nitrido diiron complex were evaluated in the oxidative transformation of hexafluorobenzene and perfluoro(allylbenzene).
- Colomban, Cédric,Kudrik, Evgeny V.,Sorokin, Alexander B.
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p. 345 - 353
(2017/08/02)
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- Preparation method for pentafluorophenol
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The invention relates to the field of organic synthesis and especially relates to a preparation method for pentafluorophenol. The preparation method comprises the steps of: 1) a Hoffmann rearrangement reaction: performing the rearrangement reaction to the compound (II) in the presence of alkali and a halogenation reagent to prepare the compound (III); 2) a diazo-hydrolysis reaction: performing a diazotization reaction to the compound (III) with a nitroso compound and performing a hydrolysis reaction in the presence of a catalyst to prepare the compound (I). The raw materials in the method are easy to obtain. The preparation method is short in synthesis route and is mild in reaction conditions, is simple in purification of the product, has high product purity and stable product quality, is low in cost of the whole synthesis route and is suitable for industrial large-scale promotion and application.
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Paragraph 0110; 0116-0118
(2017/10/12)
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- Preparation method of fluorine-containing phenol
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The invention provides a preparation method of fluorine-containing phenol. The preparation method comprises the following steps of: a) mixing a copper catalyst, a ligand, alkali, fluorine-containing bromobenzene and tertiary butanol for esterification reaction to obtain fluorine-containing phenyl tertiary butyl ester; and b) mixing the fluorine-containing phenyl tertiary butyl ester obtained in the step a) with concentrated sulfuric acid and water for hydrolysis reaction to obtain the fluorine-containing phenol. Compared with the prior art, the preparation method provided by the invention directly prepares a fluorine-containing phenyl tertiary butyl ester intermediate by adopting tertiary butanol in a breakthrough manner, and then prepares the fluorine-containing phenol through the hydrolysis reaction. The process route is simple and can be continuously operated, the reaction condition is mild, and the conventional cost of raw materials is low, and the method is suitable for industrial production; moreover, the total yield of the fluorine-containing phenol prepared by the preparation method provided by the invention can reach 76% above, and the product purity is 99% above.
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Paragraph 0094; 0096; 0097
(2017/08/29)
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- Method for preparing 2,3,4,5,6-pentafluorophenol
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The invention discloses a method for preparing 2,3,4,5,6-pentafluorophenol. The method comprises the following step of in water, performing an oxidation reaction on 2,3,4,5,6-pentafluoro phenylboronic acid as shown in the formula (VI) and hydrogen peroxide, thereby obtaining 2,3,4,5,6-pentafluorophenol as shown in the formula (VII). According to the method, an oxidation reaction is implemented in the water, so that the method is low in cost, and environmental-friendly; and besides, the method is high in reaction yield and purity and relatively applicable to industrial production.
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- Pentafluorophenol synthesis method
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The present invention relates to the field of pharmaceutical chemistry, more particularly to a pentafluorophenol synthesis method. According to the present invention, based on the problems of complex process and high production cost of the existing synthesis route in the industrial production, a completely-new pentafluorophenol synthesis method is provided, wherein pentafluorobenzene is adopted as a raw material and is subjected to one-step oxidation through hydrogen peroxide under the effect of a catalyst, such that the synthesis cost is low, the process is simple, and the method is suitable for industrial mass production.
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Paragraph 0025-0048
(2017/05/26)
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- Preparation method of pentafluorophenol
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The invention relates to the field of organic synthesis and in particular relates to a preparation method of pentafluorophenol. The structural formula of pentafluorophenol is as shown in a formula I. The preparation method specifically comprises the following steps of: (1) decarboxylic reaction; (2) Grignard reaction; and (3) oxidizing reaction. According to the preparation method of pentafluorophenol, raw materials are easily available and are low in cost, the production cost is low, the waste of bromine resources is avoided, and adverse effects on the environment are reduced; meanwhile, the preparation method of pentafluorophenol is mild in reaction condition, high in process safety, few in product impurity, easy in extraction and purification and stable in quality; and the content of pentafluorophenol obtained by refining is greater than 99%, so that the preparation method is completely suitable for large-scale industrial production.
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Paragraph 0118-0119; 0123; 0127; 0131
(2017/08/29)
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- A five-fluoro phenol preparation method (by machine translation)
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The invention relates to a five-fluoro phenol preparation method, which belongs to the field of the synthesized compounds. 1 the method comprises the following process steps: five fluoro bromobenzene drop containing magnesium and iodine is added to the organic solvent to obtain Grignard reagent; the resulting Grignard reagent drop to - 20 - 30 °C borate B (OR)3 In the organic solvent solution to carry out the esterification reaction; the resulting five-fluorophenylboronic acid spectrum ether solution with the peroxide in the 10 - 50 °C reaction, the organic solvent is cyclopentyl methyl ether or recovery of the spectrum methyl ether. The present invention only the cyclopentyl methyl ether or recovery of the spectrum methyl ether as the reaction solvent, the solvent refined recovery is, at the same time, the three-step reaction only uses one kind of solvent, solvent variety is single, reduce the operation steps, the production cost is reduced. At the same time the method provided by this invention raw materials are easy, and the process is stable, the operation is convenient, high purity of the product (≥ 99.5%). (by machine translation)
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Paragraph 0033; 0036; 0041; 0046; 0051; 0056; 0061; 0066
(2017/08/31)
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- A synthetic phenol method of multi-fluoro compounds (by machine translation)
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A synthetic phenol method of multi-fluoro compounds, Chinese the solvent, the compound (I) under the action of the catalyst, the reaction temperature 100-180°C, the reaction pressure of 0.3-2.0 MPa, the reaction time 6-12h react under, and then the step (a) in the reaction materials of the formula (II) compound of a post-processing, the process yield can be up to 80% or more, is far higher than the yield of the process the obtained in the past, to achieve product purity 99.5% or more, good color appearance, with mild reaction conditions, high yield, low cost and environment-friendly and the like. (by machine translation)
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Paragraph 0031
(2016/10/20)
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- Method for synthesizing 2,3,4,5,6-pentafluorophenol
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The invention relates to a method for synthesizing 2,3,4,5,6-pentafluorophenol. The method comprises the steps of: performing hydrolyzation on 2,3,4,5,6-pentafluro-1-halogeno benzene in the presence of a catalyst and an alkali to obtain a 2,3,4,5,6-pentafluorophenol sodium salt; and then performing treatment in the presence of a zeolite catalyst to obtain the 2,3,4,5,6-pentafluorophenol. After the catalyst is recovered, the catalyst still maintains a high catalytic efficiency, so that the production cost is lowered and the environmental pollution is reduced.
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Paragraph 0112; 0118; 0119
(2016/10/24)
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- A new method for the hydrolysis of the compound
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The invention discloses new methods for compound hydrolysis, relates to the field of drug synthesis, and particularly relates to the organic synthesis field. A drug intermediate compound I and an isomer compound II thereof in a reaction are hydrolyzed to obtain raw materials pentafluorophenol, phenol and L-alanine for re-converting to prepare the drug intermediate compound I. The two provided novel routes have the characteristics of low cost, few by-products, high yield and less environmental pollution.
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Paragraph 0025-0027
(2017/03/08)
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- BIODEGRADABLE ORGANIC RADICAL-FUNCTIONALIZED POLYCARBONATES FOR MEDICAL APPLICATIONS
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Paramagnetic, amphiphilic, biocompatible polymers were prepared comprising a carbonate repeat unit bearing a paramagnetic organic radical, more specifically a nitroxyl radical. The radical polymers can be produced in one step from a precursor polymer bearing an active ester side chain by treating the precursor polymer with a radical-bearing nucleophile. The precursor polymer can be prepared by organocatalyzed catalyzed ring opening polymerization (ROP) of a cyclic carbonate monomer bearing an active ester side chain. The radical polymers can be non-toxic and partially biodegradable. The radical polymers have utility as contrast enhancing agents in a medical imaging application and/or as therapeutic agents for treating a medical condition. The radical polymers can also serve as carriers for therapeutic agents (e.g., drugs) and/or medical image enhancing agents (e.g., NIRF dyes).
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Paragraph 0230; 0231
(2016/08/29)
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- Method for synthesizing pentafluorophenol by using continuous flow reaction
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The invention discloses a method for synthesizing pentafluorophenol by using a continuous flow reaction. By virtue of a special design of a micro-channel reactor, a two-step continuous reaction where an intermediate is not separated can be realized for realizing continuous production, and meanwhile, independent temperature control is available in each step, so that a multi-temperature region reaction which cannot be achieved in a kettle reactor can be achieved. The total yield of the optimum condition three-step reaction is greater than 80% and the product liquid phase detection purity is greater than 99%. According to the method disclosed by the invention, the production period is greatly shortened, the conversation rate is increased, the side reactions are reduced, and the production cost is lowered; the method is simple in operating process, stable in process, little in pollution, high in safety, high in product purity, free of amplification effect and suitable for industrial production on a large scale.
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Paragraph 0058; 0059; 0063; 0064; 0065
(2016/10/08)
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- By means of a micro channel reactor method of synthesizing five fluoro phenol
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The invention relates to a method for synthesizing pentafluorophenol by using microchannel reactors, which has the advantages of high reaction speed, short production cycle, low cost and high product purity. The method comprises the following steps: connecting three microchannel reactors in series, and dissolving pentafluorobromobenzene in an ether solvent to obtain a homogeneous mixed solution; respectively pumping the homogeneous mixed solution and an n-butyllithium n-hexane solution into a reactor I to react, thereby obtaining a reaction solution I; respectively pumping borate and the reaction solution I in a volume flow ratio of 1:(5-15) into a reactor II to react, thereby obtaining a reaction solution II; adding dilute hydrochloric acid into the reaction solution II for neutralization until the pH value is 1-3, standing, carrying out oil-water separation, and obtaining a pentafluorobenzene boric acid solution in the oil phase; pumping a 30 mol% oxydol solution and the pentafluorobenzene boric acid solution in a volume flow ratio of 1:(0.5-5) into a reactor III, and reacting to obtain a pentafluorophenol crude product solution; adding a 10 wt% sodium sulfite solution, removing excessive oxydol, washing with water, drying, and rectifying under vacuum to obtain the pentafluorophenol.
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Paragraph 0017; 0023-0024; 0025; 0031-0032; 0033-0112
(2020/05/05)
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- General method for the preparation of active esters by palladium-catalyzed alkoxycarbonylation of aryl bromides
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A useful method was developed for the synthesis of active esters by palladium-catalyzed alkoxycarbonylation of (hetero)aromatic bromides. The protocol was general for a range of oxygen nucleophiles including N-hydroxysuccinimide (NHS), pentafluorophenol (PFP), hexafluoroisopropyl alcohol (HFP), 4-nitrophenol, and N-hydroxyphthalimide. A high functional group tolerance was displayed, and several active esters were prepared with good to excellent isolated yields. The protocol was extended to access an important synthetic precursor to the HIV-protease inhibitor, saquinavir, by formation of an NHS ester followed by acyl substitution.
- De Almeida, Angelina M.,Andersen, Thomas L.,Lindhardt, Anders T.,De Almeida, Mauro V.,Skrydstrup, Troels
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p. 1920 - 1928
(2015/02/19)
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- Catalytic defluorination of perfluorinated aromatics under oxidative conditions using N-bridged diiron phthalocyanine
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Carbon-fluorine bonds are the strongest single bonds in organic chemistry, making activation and cleavage usually associated with organometallic and reductive approaches particularly difficult. We describe here an efficient defluorination of poly- and perfluorinated aromatics under oxidative conditions catalyzed by the μ-nitrido diiron phthalocyanine complex [(Pc)Fe III(μ-N)FeIV(Pc)] under mild conditions (hydrogen peroxide as the oxidant, near-ambient temperatures). The reaction proceeds via the formation of a high-valent diiron phthalocyanine radical cation complex with fluoride axial ligands, [(Pc)(F)FeIV(μ-N)FeIV(F) (Pc+?)], which was isolated and characterized by UV-vis, EPR, 19F NMR, Fe K-edge EXAFS, XANES, and Kβ X-ray emission spectroscopy, ESI-MS, and electrochemical techniques. A wide range of per- and polyfluorinated aromatics (21 examples), including C6F6, C6F5CF3, C6F5CN, and C6F5NO2, were defluorinated with high conversions and high turnover numbers. [(Pc)FeIII(μ-N)Fe IV(Pc)] immobilized on a carbon support showed increased catalytic activity in heterogeneous defluorination in water, providing up to 4825 C-F cleavages per catalyst molecule. The μ-nitrido diiron structure is essential for the oxidative defluorination. Intramolecular competitive reactions using C6F3Cl3 and C6F3H 3 probes indicated preferential transformation of C-F bonds with respect to C-Cl and C-H bonds. On the basis of the available data, mechanistic issues of this unusual reactivity are discussed and a tentative mechanism of defluorination under oxidative conditions is proposed.
- Colomban, Cédric,Kudrik, Evgenij V.,Afanasiev, Pavel,Sorokin, Alexander B.
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supporting information
p. 11321 - 11330
(2014/11/07)
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- Formation of polyfluorinated azobenzenes and azophenols in the reactions of chloropentafluoro-cyclohexa-2,5- and -2,4-dienones with phenyl- and pentafluorophenylhydrazines
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4-Chloropentafluorocyclohexa-2,5-dienone reacted with phenyl- and pentafluorophenylhydrazines in the presence of AlCl3 via addition to the carbonyl group with formation of the corresponding azobenzenes. The reaction of 6-chloropentafluorocycloh
- Kovtonyuk
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- Synthesis of K[4-ROC6F4BF3] from potassium pentafluorophenyltrifluoroborate and O-nucleophiles
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A new route to potassium polyfluoroaryltrifluoroborates, K[4-ROC 6F4BF3], consisting in the nucleophilic alkoxydefluorination of K[C6F5BF3] with MOR (M = K, Na) in a polar aprotic solvent is suggested. Reaction of K[C 6F5BF3] with KO-t-Bu proceeds smoothly at 25 °C in DME, but the attempted alkoxydefluorination of K[C6F 5BF3] with other NaOR at 30 °C in DME failed. A series of K[4-ROC6F4BF3] (R = Me, Et, Pr, i-Pr, Bu, PhCH2) is prepared using the corresponding sodium alkoxides in DMF at 130 °C in 80-90% isolated yield. Salt K[4-CH2CHCH 2OC6F4BF3] is prepared at 100 °C whereas at 130 °C formation of 2,3,5,6-C6F4HOCH 2CHCH2 occurs. Salt K[4-PhOC6F 4BF3] is obtained in 82% yield using KOPh (2 equivalents) in DMSO at 130 °C.
- Shabalin, Anton Yu.,Adonin, Nicolay Yu.,Bardin, Vadim V.,Prikhod'Ko, Sergey A.,Timofeeva, Maria N.,Bykova, Maria V.,Parmon, Valentin N.
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- DIPEPTIDE MIMETICS OF NGF AND BDNF NEUROTROPHINS
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The invention relates to compounds having either agonist or antagonist activities for the neurotrophins NGF and BDNF and represented by monomeric or dimeric substituted dipeptides that are analogs of the exposed portions of loop 1 or loop 4 regions of these neurotrophins near or at a beta-turn of the respective loop. N-acylated substituents of these dipeptides are biostereoisomers of the amino acid residues preceding these dipeptide sequences in the neurotrophin primary structure. The dimeric structure is produced advantageously by using hexamethylenediamine to which dipeptides are attached via their carboxyl groups. The claimed compounds displayed neuroprotective and differentiation-inducing activities in cellular models and enhanced the amount of phosphorylated tyrosine kinase A and the heat shock proteins Hsp32 and Hsp70 in the concentration range of 10?9 to 10?5 M. They also displayed neuroprotective, anti-parkinsonian, anti-stroke, anti-ischemic, anti-depressant and anti-amnestic activities in animal models and were active in experimental models of Alzheimer's disease. These in vivo effects of the claimed compounds are displayed in the dose range of 0.01 to 10 mg/kg when administered intraperitoneally.
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- Acid-catalyzed polyfluoroarylation of arenes with polyfluorinated mono- and tris(phenoxy)-1-oxaspiro[2.5]octa-4,7-dienes
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4,5,6,7,8-Pentafluoro-6-pentafluorophenoxy-1-oxaspiro[2.5]octa-4,7-diene and 4,6,8-tri-fluoro-5,6,7-tris(pentafluorophenoxy)-1-oxaspiro[2.5]octa-4,7- diene react with electron-rich arenes in the presence of AlCl3 or H2SO4 to give polyfluorinated phenoxybiaryls.
- Kovtonyuk,Kobrina
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experimental part
p. 2021 - 2026
(2012/09/07)
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- Iron catalyzed competitive olefin oxidation and ipso-hydroxylation of benzoic acids: Further evidence for an FeV=O oxidant
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The iron complex [FeII(TPA)(CH3CN) 2](OTf)2 (1) [TPA = tris(2-pyridylmethyl)amine] with H2O2 as an oxidant performs ipso-hydroxylation of electron-withdrawing benzoic acids at room temperature, leading to multiple turnovers of corresponding phenols. ipso-Hydroxylation competes with olefin epoxidation and cis-dihydroxylation in the presence of olefins, with the product ratios being modulated by the relative amounts of benzoic acid, olefin, and water. It is proposed that benzoic acid and water compete for the available sixth site on the [(TPA)FeIII(OOH)] intermediate, which undergoes O-O bond heterolysis to form, respectively, the FeV(O)(O2CAr) and FeV(O)(OH) oxidants that determine the product outcome. The putative FeV(O)(O2CAr) oxidant decays either by undergoing oxidative decarboxylation and subsequent ipso-hydroxylation to form the observed phenol product or by oxo-transfer to olefins to form epoxide. The observed higher yield of phenol over epoxide or cis-diol in all cases studied, where an electronwithdrawing benzoic acid is present in the reaction mixture, suggests that intramolecular decay of the putative FeV(O)-(O 2CAr) oxidant is favored over intermolecular olefin oxidation. These results support the mechanistic framework postulated for Fe(TPA) oxidative catalysis and further strengthens the notion that oxoiron(V) species are the key oxidants in these reactions.
- Das, Parthapratim,Que Jr., Lawrence
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experimental part
p. 9479 - 9485
(2011/01/06)
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- POLYMERS BEARING PENDANT PENTAFLUOROPHENYL ESTER GROUPS, AND METHODS OF SYNTHESIS AND FUNCTIONALIZATION THEREOF
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A one pot method of preparing cyclic carbonyl compounds comprising an active pendant pentafluorophenyl ester group is disclosed. The cyclic carbonyl compounds can be polymerized by ring opening methods to form ROP polymers comprising repeat units comprising a side chain pentafluorophenyl ester group. Using a suitable nucleophile, the pendant pentafluorophenyl ester group can be selectively transformed into a variety of other functional groups before or after the ring opening polymerization.
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Page/Page column 13
(2010/12/29)
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- Bis(pentafluorophenylxenonium) tetrafluoroterephthalate, p-C6F5XeO(O)CC6F4C(O)OXeC6F5, a hypervalent compound with two xenon-carbon bonds
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Bis(pentafluorophenylxenonium) tetrafluoroterephthalate (1) was obtained by metathesis reactions of pentafluorophenylxenonium and tetrafluoroterephthalate salts. The availability of suitable solvents for the metatheses hampered the optimization of the rea
- Bilir, Vural,Bl?ser, Dieter,Boese, Roland,Frohn, Hermann-Josef
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experimental part
p. 824 - 829
(2010/02/28)
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- Photocatalytic cleavage of C-F bond in pentafluorobenzoic acid with titanium dioxide-P25
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The photocatalytic C-F bond cleavage in pentafluorobenzoic acid (PFBA) with TiO2-P25 using UV-C light has been investigated under different conditions. Complete cleavage of C-F is observed with TiO2-P25 under UV-C light irradiation.
- Ravichandran,Selvam,Muruganandham,Swaminathan
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p. 1204 - 1210
(2008/09/20)
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- Metal ion promoted transesterifications of carboxylate esters. A structure/activity study of the efficacy of Zn2+ and La3+ to catalyze the methanolysis of some aryl and aliphatic esters
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The methanolysis of various aryl and aliphatic carboxylate esters promoted by methoxide, 1,5,9-triazacyclododecane: Zn2+(-OCH 3) and La3+(-OCH3), were studied and the derived rate constants (kOCH3, kcat 3:Zn(OCH3) and kcatLa(OCH3)) correlated in various ways. The metal ion catalyzed reactions are very much faster than the background reactions in some cases reaching up to 7 × 106-fold acceleration when present at concentrations of 5 mmol dm-3. The data for both metals exhibit non-linear Bronsted correlations with the pK a of the leaving group which are analyzed in terms of a change in rate limiting step from formation to breakdown of a metal-coordinated tetrahedral intermediate as the pKa increases above values of ~14.7. Plots of the log kOCH3 reaction vs. the log k cat, values for each metal ion indicate low sensitivity for aryl esters and a higher sensitivity for the aliphatic esters. A mechanistic rationale for the observations is presented.
- Neverov, Alexei A.,Sunderland,Brown, R. Stan
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- METHOD FOR PRODUCING FLUOROPHENOL COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing a fluorophenol compound enabling the synthesis of the fluorophenol compound by a single stage reaction process. SOLUTION: A fluorophenol compound is produced by reacting a (fluorinated aryl)boron compound expressed by general formula (1) with a peroxide. In the formula, R1, R2, R3, R4 and R5 are each independently a hydrogen atom, a fluorine atom, a hydrocarbon group or an alkoxy group; at least one of R1 to R5 is a fluorine atom; R6 is a hydrocarbon group; and n is an integer of 1-3.
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Page/Page column 10-11
(2008/06/13)
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- Mechanistic studies of la3+- And Zn2+-catalyzed methanolysis of aryl phosphate and phosphorothioate triesters. Development of artificial phosphotriesterase systems
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The methanolyses of a series of O,O-diethyl O-aryl phosphates (2,5) and O,O-diethyl S-aryl phosphorothioates (6) promoted by methoxide and two metal ion systems, (La3+)2(-OCH3)2 and 4:Zn2+:-OCH3 (4 = 1,5,9- triazacyclododecane) has been studied in methanol at 25°C. Bronsted plots of the log k2 values vs. sspKa for the phenol leaving groups give βlg values of -0.70. -1.43 and -1.12 for the methanolysis of the phosphates and -0.63, -0.87 and -0.74 for the methanolysis of the phosphorothioates promoted by the methoxide, La 3+ and Zn2+ systems respectively. The kinetic data for the metal-catalyzed reactions are analyzed in terms of a common mechanism where there is extensive cleavage of the P-XAr bond in the rate-limiting transition state. The relevance of these findings to the mechanism of action of the phosphotriesterase enzyme is discussed. The Royal Society of Chemistry 2005.
- Liu, Tony,Neverov, Alexei A.,Tsang, Josephine S.W.,Brown, R. Stan
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p. 1525 - 1533
(2007/10/03)
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- Novel stabilized activated derivatives of carbamic acid, their process of preparation and their use for the preparation of ureas
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Process for the preparation of stable activated derivatives of carbamic acid, comprising at least one protected amino group and an activated carbamic acid function, from an amino acid derivative in which the amino group is protected. The process includes: a) a step of transformation of the —COOH group of the amino acid derivative into a —CON3 group to obtain an acyl azide; b) a step of transformation of the —CON3 group of the acyl azide into a —NCO group to obtain an isocyanate; c) a step of treating the isocyanate to obtain a stable derivative of carbamic acid.
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- Synthesis of model tricyclic C-O-D-O-E-F-O-G ring of teicoplanin
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Synthesis of model tricyclic C-O-D-O-E-F-O-G rings (2) of teicoplanin (1) by means of efficient S(N)Ar based cyclocetherification methodology is reported.
- Bois-Choussy, Michele,Vergne, Caroline,Neuville, Luc,Beugelmans, Rene,Zhu, Jieping
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p. 5795 - 5798
(2007/10/03)
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- Evidence for an Alternative Mechanism to a Previously Proposed Self-Replicating System
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Rebek et al.1,2 have proposed a "self-replicative" mechanism in which the amide product of an ester aminolysis forms a termolecular complex with the ester and amine reactants.In this manner, the product catalyzes its own formation.The evidence for the mechanism lies mainly in a 40-70percent acceleration when product is added externally to the reaction mixture.The system has now been reinvestigated owing, in part, to doubts created by troublesome experimental problems (e.g. small rate enhancements coupled to >/= 35percent unidentified side reactions) and by the entropic unlikehood of the highly constrained termolecular complex.Our new experiments prove that the Rebek mechanism is unnecessary.Thus, the aminolysis of simple naphthoyl and benzoyl esters, both lacking any hydrogen-bonding sites, are catalyzed by the Rebek "template".In the latter case, the reactions were run under the identical conditions used recently by Rebek (2 mM) while monitoring the formation of the major reaction product.Although the benzoyl ester cannot hydrogen-bond to the template, the ester aminolysis is catalyzed by the template to an extent even greater than that observed by Rebek (i.e. 2-fold).The Rebek mechanism, predicted upon ester/template binding, is clearly invalidated by these experiments.An alternative mechanism, involving amide catalysis, is proposed and found consistent with all available data.
- Menger, F. M.,Eliseev, A. V.,Khanjin, N. A.,Sherrod, M. J.
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p. 2870 - 2878
(2007/10/02)
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- Stability of activated phenyl esters of carboxylic acids in polar aprotic media
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The reaction of activated phenyl esters of carboxylic acids with weakly basic aprotic solvents was investigated.It was established that only the most active 2,4-dinitrophenyl esters are subject to conversions with perceptible rate, principally hydrolysis.In weakly basic inert organic solvents triethylamine practically does not react with activated esters, while in HMPTA in accelerates hydrolysis by the mechanism of basic catalysis 3-36 times in dependence on the structure of the ester.Hydrolysis of 2,4-dinitrophenyl esters in the presence of triethylamine is accompanied by the formation of the intermediate anhydride as a result of acylation of the resulting carboxylic acid by the starting ester.It is shown that in aminolysis reactions an increase of the activity of the ester contributes to suppression of the competing reaction of hydrolysis.
- Katsarava, R.D.,Kharadze, D.P.
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p. 2241 - 2246
(2007/10/02)
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- Perfluoro- and Polyfluoro-sulphonic Acids. Part 22. Polyfluorophenyl Pentafluorobenzenesulphonates and their Electron Transfer Reaction with Sodium Iodide
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Polyfluorophenyl pentafluorobenzenesulphonates (1) have been synthesized in excellent yields by the reaction of pentafluorobenzenesulphonyl chloride with polyfluorophenoxides.Nucleophilic attack on 1 resulted in the breakage of the S-O bond accompanied by displacement of o- and /or p-fluorine.Reaction of 1 with sodium iodide (8) in a mole ratio of 1:3 (1:8) yielded polyfluorodiphenyl ethers 9 and 10 as the main products.However, p-C6F5OC6F4SO3C6F5 (12) was isolated as the major product in addition to 9 and 10 when the reactant ratio was 1:1 or 1:0.25.Reaction of 12 with sodium iodide also gave 9 and 10 when the reactant ratio was 1:3 (12:8).The reaction of 1 (or 12) with NaI is supposed to be an electron-transfer process.
- Chen, Qing-Yun,Chen, Ming-Fang
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p. 1071 - 1075
(2007/10/02)
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- REACTION OF POLYFLUORINATED AROMATIC COMPOUNDS WITH SODIUM NITRITE
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The reactions of polyfluorinated aromatic compounds with sodium nitrite lead to the formation of products from N- and O-substitution of the fluorine atoms in the aromatic ring.The increase in the nucleophilic mobility of the fluorine atoms with the introduction of electron-withdrawing substituents into the ring promotes the formation of the O-substitution products.
- Miller, A. O.,Furin, G. G.
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p. 317 - 319
(2007/10/02)
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- Synthesis and Chemistry of Highly Fluorinated Bicyclohexenone
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A series of highly fluorinated bicyclo-5-hexen-2-ones (3) and their hydrates (4) have been prepared in two steps from hexafluoro Dewar benzene (1).Photolysis of exo-3H-pentafluorobicyclo-5-hexen-2-one (3d) at low pressure in the vapor phase gave 1H-pentafluorocyclopentadiene (8), but in solution the principal product was pentafluorophenol (9).Under Favorskii conditions, exo-3-bromo- and exo-3-chloropentafluorobicyclo-5-hexen-2-one (3a and 3b) ring opened stereospecifically to 2-cyclobutenecarboxylic acids 17 and 29, respectively.Treatment of these ketones with tert-butoxide under aprotic conditions effected stereospecific cleavage to tert-butyl methylenecyclobutenecarboxylates 25 and 30.The acid (27) corresponding to 25 was obtained both from bromohydrate 4a and the acid 17, again stereospecifically, by reaction with lithium diisopropylamide.Flash vacuum pyrolysis of the hydrate (4c) of of hexafluorobicyclo-5-hexen-2-one at 300 deg C gave hexafluoro-2,4-cyclohexadienone (12), which decarbonylated at higher temperatures to yield hexafluorocyclopentadiene (13).Similarly, flash vacuum pyrolysis of 3-chloropentafluorobicyclo-5-hexen-2-one (3b) at 650 deg C gave a mixture of 1- and 2-chloropentafluorocyclopentadienes.
- Soelch, Richard R.,McNierney, Edward,Tannenbaum, Gary A.,Lemal, David M.
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p. 5502 - 5511
(2007/10/02)
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- Concertedness in Acyl Group Transfer in Solution: A Single Transition State in Acetyl Group Transfer between Phenolate Ion Nucleophiles
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Rate constants have been measured for nucleophilic substitution of 4-nitrophenol from 4-nitrophenyl acetate by a series of phenolate anions.The Bronsted type plot is linear for unhindered phenolate ions with pKa values significantly above and below that of the displaced 4-nitrophenol: (log kArO = 0.75pKArOH - 7.28; n = 17, r = 0.984); this is consistent with a mechanism involving a single transition state or a mechanism with an intermediate that has a very low barrier to decomposition.A small change in effective charge on the carbonyl group from reactant to transition state (measured from βnuc and the known βeq for the overall reaction) points to an almost coupled concerted mechanism for the transfer of acetyl function between phenolate ion nucleophiles.The conclusions of this work are consistent with previous results that indicate relatively stable tetrahedral intermedates in reactions at reactive acyl centers; a spectrum of mechanisms exists for substitution reactions of acyl functions in solution that ranges from SN1 (or ElcB for an ester with an α-carbanion) through concerted to BAc2.
- Ba-Saif, Salem,Luthra, Ajay K.,Williams, Andrew
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p. 6362 - 6368
(2007/10/02)
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- OXIDATION OF POLYFLUORINATED DERIVATIVES OF BENZENE WITH HYDROGEN PEROXIDE
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The thermal decomposition of hydrogen peroxide in an excess of hexafluorobenzene gives pentafluorophenol, which is formed as a result of the generation of the pentafluorophenoxyl radical under the reaction conditions.The oxidation of pentafluorophenol by hydrogen peroxide leads either to tetrakis(pentafluorophenoxy)-1,4-benzoquinone or to difluoromaleic acid, depending on the conditions.Hydroxylation of the unfluorinated aromatic ring occurs during the reactions of 2,3,4,5,6-pentafluorobiphenyl with hydrogen peroxide.
- Bogachev, A. A.,Kobrina, L. S.,Yakobson, G. G.
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p. 2313 - 2317
(2007/10/02)
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