- Electrochemical Trifluoromethoxylation of (Hetero)aromatics with a Trifluoromethyl Source and Oxygen
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Trifluoromethoxylated aromatics (ArOCF3) are valuable structural motifs in the area of drug discovery due to the enhancement of their desired physicochemical properties upon the introduction of the trifluoromethoxy group (CF3O). Although significant progress has been made recently in the introduction of CF3O group into aromatics, current methods either require the use of expensive trifluoromethoxylation reagents or require harsh reaction conditions. We present a conceptually new and operationally simple protocol for the direct C?H trifluoromethoxylation of (hetero)aromatics by the combination of the readily available trifluoromethylating reagent and oxygen under electrochemical reaction conditions. This reaction proceeds through the initial generation of CF3 radical followed by conversion to CF3O radical, addition to (hetero)aromatics and rearomatization. The utility of this electrochemical trifluoromethoxylation is illustrated by the direct incorporation of CF3O group into a variety of (hetero)aromatics as well as bio-relevant molecules.
- Ouyang, Yao,Qing, Feng-Ling,Xu, Xiu-Hua
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supporting information
(2021/12/06)
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- Method for synthesizing nitro (hetero) aromatic hydrocarbon
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The invention discloses a method for synthesizing nitro (hetero) aromatic hydrocarbon, and belongs to the field of organic synthesis. According to the method, simple (hetero) aromatic hydrocarbon is taken as an initial raw material and is stirred and reacted in an organic solvent at 40-100 DEG C under the action of a nitration reagent, a lewis acid catalyst and protective gas, and nitro (hetero) aromatic hydrocarbon can be obtained. The method provided by the invention has the advantages of cheap and easily available raw materials, mild reaction conditions, simple preparation process, good chemical selectivity, wide substrate application range, easy amplification and the like, has great application potential, and lays a good foundation for industrial production.
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Paragraph 0082-0084; 0085-0087
(2022/04/08)
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- Radical C?H Trifluoromethoxylation of (Hetero)arenes with Bis(trifluoromethyl)peroxide
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Trifluoromethoxylated (hetero)arenes are of great interest for several disciplines, especially in agro- and medicinal chemistry. Radical C?H trifluoromethoxylation of (hetero)arenes represents an attractive approach to prepare such compounds, but the high cost and low atom economy of existing .OCF3 radical sources make them unsuitable for the large-scale synthesis of trifluoromethoxylated building blocks. Herein, we introduce bis(trifluoromethyl)peroxide (BTMP, CF3OOCF3) as a practical and efficient trifluoromethoxylating reagent that is easily accessible from inexpensive bulk chemicals. Using either visible light photoredox or TEMPO catalysis, trifluoromethoxylated arenes could be prepared in good yields under mild conditions directly from unactivated aromatics. Moreover, TEMPO catalysis allowed for the one-step synthesis of valuable pyridine derivatives, which have been previously prepared via multi-step approaches.
- Dix, Stefan,Golz, Paul,Schmid, Jonas R.,Riedel, Sebastian,Hopkinson, Matthew N.
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supporting information
p. 11554 - 11558
(2021/07/09)
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- Photocatalytic trifluoromethoxylation of arenes and heteroarenes in continuous-flow
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The first example of photocatalytic trifluoromethoxylation of arenes and heteroarenes under continuous-flow conditions is described. Application of continuous-flow microreactor technology allowed to reduce the residence time up to 16 times in comparison t
- Cendón, Borja,Gulías, Moisés,Ho, Michelle,No?l, Timothy,Nyuchev, Alexander V.,Sambiagio, Carlo,Struijs, Job J. C.,Wan, Ting,Wang, Ying
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supporting information
p. 1305 - 1312
(2020/07/10)
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- NITRATION
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The present invention relates to a process for preparing a nitrated compound, comprising the step of reacting a compound (A) comprising at least one substituted or unsubstituted aromatic or heteroaromatic ring, wherein said heteroaromatic ring comprises at least one heteroatom selected from the group consisting of oxygen, sulfur, phosphor, selenium and nitrogen, with a compound of formula (I) wherein Y is selected from the group consisting of hydrogen and nitro.
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Page/Page column 36; 38; 42; 52; 66
(2020/05/28)
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- N-Nitroheterocycles: Bench-Stable Organic Reagents for Catalytic Ipso-Nitration of Aryl- And Heteroarylboronic Acids
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Photocatalytic and metal-free protocols to access various aromatic and heteroaromatic nitro compounds through ipso-nitration of readily available boronic acid derivatives were developed using non-metal-based, bench-stable, and recyclable nitrating reagents. These methods are operationally simple, mild, regioselective, and possess excellent functional group compatibility, delivering desired products in up to 99% yield.
- Budinská, Alena,Katayev, Dmitry,Passera, Alessandro,Zhang, Kun
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supporting information
(2020/03/30)
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- Visible-Light Photoredox-Catalyzed and Copper-Promoted Trifluoromethoxylation of Arenediazonium Tetrafluoroborates
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We report the development of photoredox-catalyzed and copper-promoted trifluoromethoxylation of arenediazonium tetrafluoroborates, with trifluoromethyl arylsulfonate (TFMS) as the trifluoromethoxylation reagent. This new method takes advantage of visible-light photoredox catalysis to generate the aryl radical under mild conditions, combined with copper-promoted selective trifluoromethoxylation. The reaction is scalable, tolerates a wide range of functional groups, and proceeds regioselectively under mild reaction conditions. Furthermore, mechanistic studies suggested that a Cs[Cu(OCF3)2] intermediate might be generated during the reaction.
- Yang, Shaoqiang,Chen, Miao,Tang, Pingping
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supporting information
p. 7840 - 7844
(2019/05/15)
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- Radical Trifluoromethoxylation of Arenes Triggered by a Visible-Light-Mediated N?O Bond Redox Fragmentation
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A simple trifluoromethoxylation method enables non-directed functionalization of C?H bonds on a range of substrates, providing access to aryl trifluoromethyl ethers. This light-driven process is distinctly different from conventional procedures and occurs through an OCF3 radical mechanism mediated by a photoredox catalyst, which triggers an N?O bond fragmentation. The pyridinium-based trifluoromethoxylation reagent is bench-stable and provides access to synthetic diversity in lead compounds in an operationally simple manner.
- Jelier, Benson J.,Tripet, Pascal F.,Pietrasiak, Ewa,Franzoni, Ivan,Jeschke, Gunnar,Togni, Antonio
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supporting information
p. 13784 - 13789
(2018/09/14)
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- Process Development and Scale-up of the Continuous Flow Nitration of Trifluoromethoxybenzene
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In this work, continuous flow nitration of trifluoromethoxybenzene (TFMB) was conducted in a microchannel reactor. The effects of process parameters, including temperature, residence time, sulfuric acid strength, flow rate, and reactor structure, were systemically investigated. It was found that the aforementioned process parameters had significant effect on TFMB conversion, while the product selectivity was merely sensitive to the reaction temperature. On the basis of the results of process parameter optimization, a scale-up strategy combining microreactor with distributed packed tubular reactor was presented. Consequently, excellent performance was achieved in the combined reactor with a kilogram-scale production.
- Wen, Zhenghui,Jiao, Fengjun,Yang, Mei,Zhao, Shuainan,Zhou, Feng,Chen, Guangwen
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supporting information
p. 1843 - 1850
(2017/11/24)
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- PROCESS FOR THE PREPARATION OF 4-SUBSTITUTED-1-(TRIFLUOROMETHOXY)BENZENE COMPOUNDS
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The present invention provides the process for the preparation of 4-substituted-1- (trifluoromethoxy) benzene compounds..
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Page/Page column 7; 8
(2016/09/22)
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- Catalyst free, base free microwave irradiated synthesis of aryl nitrites from potassium aryltrifluoroborates and bismuth nitrate
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A mixture of bismuth nitrate pentahydrate and potassium aryltrifluoroborate in toluene under microwave heating at 120 C for 20 min provides an interesting and mild reaction protocol for the synthesis of aryl nitrite. The conversion to aryl nitrites from aryltrifluoroborates without transition metal catalyst and base in high yields is remarkable.
- Al-Masum, Mohammad,Welch, Rebecca L.
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p. 1726 - 1728
(2014/03/21)
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- CF3 oxonium salts, O-(trifluoromethyl)dibenzofuranium salts: In situ synthesis, properties, and application as a real CF3+ species reagent
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(Chemical Equation Presented) We report in situ synthesis of the first CF3 oxonium salts, thermally unstable O-(trifluoromethyl)- dibenzofuranium salts, which furthermore have different counteranions (BF 4-, PF6-, SbF6 -, and Sb2F11-) and ring substituents (tert-butyl, F, and OCH3), by photochemical decomposition of the corresponding 2-(trifluoromethoxy)biphenylyl-2′- diazonium salts at -90 to -100°C. The yields markedly increased in the order of BF4- 6- 6- 2F11-. The CF3 oxonium salts were fully assigned by means of 1H and 19F NMR spectroscopy at low temperature. The CF3 salts decomposed to form CF4 and dibenzofurans. The half-life times at -60°C of the 2-tert-butyl salts having different counteranions were 29 min for BF4- salt 2d, 36 min for PF6- salt 2c, 270 min for SbF6- salt 2a, and 415 min for Sb2F11- salt 2b. Those at -60°C of the Sb2F11- salts having different 2-substituents were 13 min for F salt 3b, 63 min for H (unsubstituted) salt 1b, and 415 min for tert-butyl salt 2b. Thus, the stability of the CF3 oxonium salts increased in the order of BF4- 6 - 6- 2F 11- and F 3+ species source to the direct O- and N-trifluoromethylations of alcohols, phenols, amines, anilines, and pyridines under very mild conditions. The thermal decomposition method with a mixture of diazonium salt 17a and aryl- or alkylsulfonic acids, pyridine, or pyridines having an electron-withdrawing group also afforded CF3O or CF 3N products. The trifluoromethylation mechanism is discussed and an SN2 mechanism containing the transient formation of free CF 3+ is proposed. Thus, the present study has demonstrated that the exceedingly reactive CF3+ species can be generated much easier than the CH3+ species, contrary to the common sense that CF3+ is extremely difficult to generate in solution.
- Umemoto, Teruo,Adachi, Kenji,Ishihara, Sumi
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p. 6905 - 6917
(2008/02/11)
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- Process for the halogenation, nitration and fluorination of aromatic derivatives
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A process for the halogenation (bromination or chlorination)/nitration/fluorination of aromatic derivatives substituted by at least one group containing a halogenoalkyl unit. The aromatic derivative is reacted with a halogen and a nitrating agent in liquid hydrofluoric acid. The products obtained are useful as intermediates for the synthesis of compounds having a plant-protecting or pharmaceutical activity.
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- Preparation of aryl trifluoromethyl ethers
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A one-step process for the synthesis of aryl trifluoromethyl ethers by reacting phenol or certain substituted phenols with a perhalomethane and hydrogen fluoride is provided. The compounds produced by the process of this invention are useful intermediates in the production of dyestuffs and pharmaceuticals.
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