- Room-temperature nucleophilic aromatic fluorination: Experimental and theoretical studies
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(Chemical Equation Presented) Taming the reagent: The use of anhydrous tetrabutylammonium fluoride (TBAFanh) in nucleophilic aromatic substitution reactions, including variants of the selective halogen-exchange and fluorodenitration processes (see scheme), was investigated. It was shown that TBAFanh permits these reactions to be performed under surprisingly mild conditions if it is used in relatively nonpolar media.
- Sun, Haoran,DiMagno, Stephen G.
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- Metal-free dehydrosulfurization of thioamides to nitriles under visible light
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A visible light-mediated, metal-free dehydrosulfurization reaction of thioamides to nitriles is described. This reaction features high yields, mild reaction conditions, and the use of a cheap organic dye as the photoredox catalyst and air as the oxidant.
- Xu, Tianxiao,Cao, Tianpeng,Feng, Qingyuan,Huang, Shenlin,Liao, Saihu
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supporting information
p. 5151 - 5153
(2020/05/26)
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- Multiple Approaches to the in Situ Generation of Anhydrous Tetraalkylammonium Fluoride Salts for SNAr Fluorination Reactions
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This article focuses on the development of practical approaches to the in situ generation of anhydrous fluoride salts for applications in nucleophilic aromatic substitution (SNAr) reactions. We report herein that a variety of combinations of inexpensive nucleophiles (e.g., tetraalkylammonium cyanide and phenoxide salts) and fluorine-containing electrophiles (e.g., acid fluoride, fluoroformate, benzenesulfonyl fluoride, and aryl fluorosulfonate derivatives) are effective for this transformation. Ultimately, we demonstrate that the combination of tetramethylammonium 2,6-dimethylphenoxide and sulfuryl fluoride (SO2F2) serves as a particularly practical route to anhydrous tetramethylammonium fluoride. This procedure is applied to the SNAr fluorination of a range of electron-deficient aryl and heteroaryl chlorides as well as nitroarenes.
- Cismesia, Megan A.,Ryan, Sarah J.,Bland, Douglas C.,Sanford, Melanie S.
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p. 5020 - 5026
(2017/05/24)
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- A 3, 4 - difluoro phenyl nitrile synthesis process
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The invention discloses a process for synthesizing 3,4-difluorobenzonitrile. According to the process, 3,4-difluorobenzonitrile with the purity of over 99% is obtained through taking 3,4-dichlorobenzonitrile as a raw material, taking potassium fluoride as a fluorination reagent, taking 1,3-dimethyl-2-imidazolidinone as a reaction solvent, taking bis-(N-bis(dimethylamino)methylene)-iminium chloride as a catalyst, enabling reactants to react for 2-3 hours at the temperature of 130-150 DEG C and react for 5-6 hours at the temperature of 180-200 DEG C, then ending reaction, filtering a reaction solution and then rectifying under reduced pressure, and the yield can reach 85%. Rectification mother liquor (containing the catalyst) is mechanically applied to next-batch reaction directly. According to the process disclosed by the invention, the raw material is easy to obtain, the reaction conditions are mild, the reaction time is short, the operation is simple, the yield is high, the reaction solvent (containing the catalyst) can be repeatedly applied mechanically, the cost is low, and the emission of waste gases, waste water and waste residues is little, so that the process is applicable to industrial production.
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Paragraph 0040-0043
(2017/11/16)
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- A method for preparing of the benzonitrile derivatives
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The invention discloses a preparation method of a cyanobenzene derivative. The cyanobenzene derivative is prepared by taking phenylacetic acid or the derivative thereof as well as urea as raw materials, copper salt as a catalyst and oxygen as an oxidizing agent. According to the preparation method disclosed by the invention, by adopting copper salt as the catalyst and oxygen as the oxidizing agent without an extra cocatalyst, the raw materials phenylacetic acid or the derivative thereof are easy to purchase in the market, low in cost and various in type, and urea as the source of cyanogen is low in toxicity, low in price, mild in reaction condition and environmentally friendly, and has a good functional group compatibility.
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Paragraph 0021; 0022; 0023; 0054; 0055; 0056; 0057
(2016/10/17)
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- Rhodium-catalyzed transformation of heteroaryl aryl ethers into heteroaryl fluorides
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A rhodium complex catalyzed the conversion of the C-O bond of heteroaryl aryl ethers to the C-F bond. The reaction of (4-chlorophenylthio)pentafluorobenzene with heteroaryl aryl ethers provided heteroaryl fluorides and heteroaryl (4-chlorophenylthio)tetrafluorophenyl ethers; this involved the cleavage of a single heteroaryl C-O bond under equilibrium conditions. The reaction of heteroaryl aryl ethers with 2-fluorobenzothiazole in which two heteroaryl and aryl C-O bonds were cleaved provided heteroaryl fluorides and aryl fluorides. The reactions were applicable to five-membered and six-membered heteroaryl aryl ethers and also to diaryl ethers possessing one or two electron-withdrawing groups.
- Arisawa, Mieko,Tanii, Saori,Tazawa, Takeru,Yamaguchi, Masahiko
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supporting information
p. 11390 - 11393
(2016/09/23)
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- Copper-catalyzed decarboxylative C≡N triple bond formation: Direct synthesis of benzonitriles from phenylacetic acids under O2 atmosphere
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A copper-catalyzed reaction of phenylacetic acids with urea was found to afford benzonitriles under an oxygen atmosphere. This reaction proceeds smoothly by a sequence of decarboxylation, dioxygen activation, C-H bond functionalization, and nitrile formation with urea as the nitrogen source. Molecular oxygen was found to play a crucial role in this transformation. This reaction represents a novel protocol for the formation of benzonitriles in an environmental friendly way and with good functional group tolerability.
- Feng, Qiang,Song, Qiuling
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supporting information
p. 1697 - 1702
(2014/06/09)
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- Environment friendly protocol for the synthesis of nitriles from aldehydes
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A rapid and eco-friendly one-pot protocol for the synthesis of nitriles has been developed by treating various araldehydes bearing electron withdrawing as well as electron donating groups with hydroxylamine hydrochloride in the presence of non-toxic, non-corrosive and reusable zinc oxide (ZnO) as the catalyst under solvent-free microwave irradiation. The present approach offers the advantages of a clean reaction, simple methodology, employing readily available catalyst, short reaction duration (1. min), high selectivity; and high yield (90-98%).
- Madhusudana Reddy,Pasha
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experimental part
p. 1025 - 1028
(2011/10/08)
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- Efficient and high-yielding protocol for the synthesis of nitriles from aldehydes
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An operationally simple and high-yielding procedure has been developed for the conversion of araldehydes into the corresponding nitriles using p-toluenesulfonic acid (p-TSA) (a mild catalyst) under microwave irradiation. The products are characterized by infrared spectral analysis and by comparison of the melting and boiling points with the reported values. Copyright
- Reddy, M. B. Madhusudana,Pasha
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experimental part
p. 3384 - 3389
(2010/12/25)
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- Process for preparing nuclear-fluorinated aromatics
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The present invention relates to the preparation of nuclear-fluorinated aromatics by reacting, with a fluoride at 40 to 260° C., an aromatic compound substituted at the nucleus with halogen that is exchangeable for fluorine in the presence of at least one compound of the formula (I) where A, B, and Any have the meanings specified in the disclosure.
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- SYNTHESIS OF 3,4-DIFLUOROBENZONITRILE AND MONOFLUOROBENZONITRILES BY MEANS OF HALOGEN-EXCHANGE FLUORINATION
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3,4-Difluorobenzonitrile has been prepared by a halogen-exchange reaction between 3,4-dichlorobenzonitrile and spraydried potassium fluoride in the presence of tetraphenylphosphonium bromide in refluxing 1,3-dimethylimidazolidine-2-one.In the fluorination reaction, 4-chloro-3-fluorobenzonitrile seems to be a key intermediate. 3,4-Difluorobenzonitrile, 2-, 3-, and 4-fluorobenzonitriles have also been produced from the corresponding chlorobenzonitrile derivatives by halogen-exchange at 290 deg C, in DMI in a pressure reactor.
- Suzuki, Hiroshi,Kimura, Yoshikazu
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p. 341 - 351
(2007/10/02)
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