- Mechanistic insights into boron-catalysed direct amidation reactions
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The generally accepted monoacyloxyboron mechanism of boron-catalysed direct amidation is brought into question in this study, and new alternatives are proposed. We have carried out a detailed investigation of boron-catalysed amidation reactions, through study of the interaction between amines/carboxylic acids and borinic acids, boronic acids and boric acid, and have isolated and characterised by NMR/X-ray crystallography many of the likely intermediates present in catalytic amidation reactions. Rapid reaction between amines and boron compounds was observed in all cases, and it is proposed that such boron-nitrogen interactions are highly likely to take place in catalytic amidation reactions. These studies also clearly show that borinic acids are not competent catalysts for amidation, as they either form unreactive amino-carboxylate complexes, or undergo protodeboronation to give boronic acids. It therefore seems that at least three free coordination sites on the boron atom are necessary for amidation catalysis to occur. However, these observations are not consistent with the currently accepted 'mechanism' for boron-mediated amidation reactions involving nucleophilic attack of an amine onto a monomeric acyloxyboron intermediate, and as a result of our observations and theoretical modelling, alternative proposed mechanisms are presented for boron-mediated amidation reactions. These are likely to proceed via the formation of a dimeric B-X-B motif (X = O, NR), which is uniquely able to provide activation of the carboxylic acid, whilst orchestrating the delivery of the amine nucleophile to the carbonyl group. Quantum mechanical calculations of catalytic cycles at the B3LYP+D3/Def2-TZVPP level (solvent = CH2Cl2) support the proposal of several closely related potential pathways for amidation, all of which are likely to be lower in energy than the currently accepted mechanism.
- Arkhipenko, Sergey,Sabatini, Marco T.,Batsanov, Andrei S.,Karaluka, Valerija,Sheppard, Tom D.,Rzepa, Henry S.,Whiting, Andrew
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- Preparation method of 3, 4, 5-trifluorophenylboronic acid
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The invention provides a preparation method of 3, 4, 5-trifluorophenylboronic acid, and belongs to the technical field of pharmaceutical chemicals. According to the method, 3, 4, 5-trifluorobromobenzene is taken as a raw material, and 3, 4, 5-trifluorophenylboronic acid is prepared through Grignard reaction. According to the method, the 3, 4, 5-trifluorophenylboronic acid is prepared by adopting a two-way dropwise adding method, the Grignard reagent preparation and the Grignard reaction are simultaneously carried out, and the Grignard reaction is carried out while the Grignard reagent is prepared, so that the concentration of the Grignard reagent in a reaction system is reduced, the side reactions of coupling and disubstitution are reduced, the yield and the purity are improved, and the cost is obviously reduced.
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Paragraph 0028-0039
(2022/04/06)
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- PROCESS FOR THE PREPARATION OF BIPHENYLAMINES
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The invention relates to a method for the preparation of 2-aminobiphenyls, key intermediates in the preparation of compounds of interest in the agrochemical industry. The process comprises reacting an ortho-substituted aniline and a phenylboro derivative in the presence of a base and a palladium catalyst, said palladium catalyst comprising a palladium source and a biphenyl phosphine ligand of formula (III) or a salt thereof
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Page/Page column 23-24
(2021/01/29)
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- Application method of Grignard reaction
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The invention discloses an application method of a Grignard reaction, belonging to the technical field of organic synthesis. According to the invention, a two-way dropwise adding mode is adopted, andpreparation of a Grignard reagent and a Grignard reaction are carried out at the same time; as the Grignard reaction is carried out while the Grignard reagent is prepared, the concentration of the Grignard reagent in a reaction system is reduced, and coupling side reactions are reduced; the use amount of a solvent in the reaction system is reduced, the accumulation rate of raw materials is increased, yield is increased and cost is reduced; and meanwhile, in the reaction system, the activity of the Grignard reagent in the system is reduced due to the reduction of the concentration of the Grignard reagent, so an explosion risk caused by over-high concentration of the Grignard reagent during storage and reaction of the Grignard reagent is avoided.
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Paragraph 0040-0049
(2021/03/31)
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- Efficient and Practical Synthesis of 3′,4′,5′-Trifluoro-[1,1′-biphenyl]-2-amine: A Key Intermediate of Fluxapyroxad
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An improved and practical method is reported here for accessing 3′,4′,5′-trifluoro-[1,1′-biphenyl]-2-amine (1), a key intermediate for Fluxapyroxad. The overall yield for the preparation of 1 was 73%, with a purity of 99.88%, after a three-step process. More importantly, this process was an improvement in the manufacture of biphenyl compounds by Suzuki-Miyaura coupling, which enabled catalyst loading as low as 0.04 mol %. This method could provide an economic and environment-friendly process leading to extensive prospects in industrial applications.
- Li, Zhenhua,Zhang, Xuchao,Qin, Jinjing,Tan, Zhiyong,Han, Meizhen,Jin, Guoqiang
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supporting information
p. 1881 - 1886
(2019/09/30)
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- A 3 ', 4', 5' - trifluoro -2 - amino biphenyl chemical synthesis method
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The invention discloses a 3 ', 4', 5 '- trifluoro - 2 - amino biphenyl chemical synthesis method, it to 3, 4, 5 - trifluoro bromobenzene as the starting material, passes through formatting reaction, reaction and coupling reaction to obtain a sediment 3', 4 ', 5' - trifluoro - 2 - nitro-biphenyl, 3 ', 4', 5 '- trifluoro - 2 - nitro-biphenyl through catalytic reduction reaction to obtain the target product 3', 4 ', 5' - trifluoro - 2 - phenylaniline. The present invention provides compound 3 ', 4', 5' - trifluoro - 2 - amino biphenyl synthesis of new routes, the advantages of the simple process operation, mild reaction conditions, high yield, is simple in separation purification. Wherein the 3 ', 4', 5' - trifluoro - 2 - nitro-biphenyl synthesis in the process, the catalyst consumption is low, and the production cost is reduced, more suitable for large-scale industrial application.
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Paragraph 0061-0069
(2019/07/11)
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- A 3 ', 4', 5 '- trifluoromethyl - [1, 1' - biphenyl] -2 - amine chemical synthesis method
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The invention discloses a 3 ', 4', 5 '- trifluoromethyl - [1, 1' - biphenyl] - 2 - amine chemical synthesis method, of formula (IV) is shown in the 3 ', 4', 5 '- trifluoromethyl - [1, 1' - biphenyl] - 2 - carboxamide sodium hypohalite in dispersed in aqueous solution, in the presence of a, at a temperature of 5 - 7 °C reaction 1 - 3 the H, then heating to 70 - 73 °C continue to reaction 0.5 - 1.5 h, after the reaction, processing reaction liquid formula (V) is shown in the 3 ', 4', 5 '- trifluoromethyl - [1, 1' - biphenyl] - 2 - amine; . Through the method of the present invention 3 ', 4', 5 '- trifluoromethyl - [1, 1' - biphenyl] - 2 - amine has high yield, mild reaction conditions, operation is simple and easy, is suitable for large-scale industrial production method. This is production [...] amide provides another feasibility is high choice, by 3, 4, 5 - trifluoro bromophenylacetic soluble acidification, coupling, hydrolysis and degradation and other steps 3 ', 4', 5 '- trifluoromethyl - [1, 1' - biphenyl] - 2 - amine of the new route.
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Paragraph 0076-0093
(2019/06/05)
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- Method for Producing Substituted Biphenyls
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A process for preparing substituted biphenyls of the formula I where R1=nitro or amino, R2=cyano, halogen, C1-C4-haloalkyl, C1-C4-haloalkoxy or C1-C4-haloalkylthio,n=from 0 to 3, and R3=hydrogen, cyano or halogen, which comprises reacting a halobenzene of the formula II in which Hal is chlorine or bromine, in the presence of a base and of a palladium catalyst which consists of palladium and a bidentate phosphorus ligand of the formula III where Ar is phenyl which is substituted if desired and R4 and R5 are each C1-C8-alkyl or C3-C6-cycloalkyl or together form a 2- to 7-membered bridge which may, if desired, bear a C1-C6-alkyl substituent, in a solvent or diluent, with a phenylboronic acid IVa a diphenylborinic acid IVb or a mixture of IVa and IVb.
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Page/Page column 4
(2011/05/08)
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- Polyfluoroorganoboron-oxygen compounds. 1: Polyfluorinated aryl(dihydroxy)boranes and tri(aryl)boroxins
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A general preparative procedure for polyfluorinated aryl(dihydroxy)boranes C6H5-nFnB(OH)2 (n = 3 - 5) is described. Polyfluorinated aryl(dihydroxy)boranes are easily dehydrated to the corresponding tri(aryl)boroxins (C6H5-nFnBO)3 by thermal or chemical treatment. The property of the acids C6H5-nFnB(OH)2 to condensate depends on the number and on the position of the fluorine atoms in the aryl group. Examples of both classes of boron compounds were isolated as pure individuals and characterized by multinuclear NMR spectroscopy.
- Frohn,Adonin,Bardin,Starichenko
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p. 2827 - 2833
(2008/10/08)
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- COMPOUND HAVING TETRAHYDRONAPHTHALENE SKELETON AND LIQUID CRYSTAL COMPOSITION CONTAINING THE SAME
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A tetrahydronaphthalene derivative represented by the general formula (I) and a liquid crystal composition containing the same. A compound represented by the general formula (I) shows superior liquid crystallinity and co-solubility with conventional liquid crystal compounds and compositions. Furthermore, addition of such a compound enables the threshold voltage to be significantly reduced with almost no deleterious effect on the responsiveness. In addition, a compound of the present invention can also be easily produced industrially, is colorless, and is chemically stable. Consequently, liquid crystal compositions containing such a compound are extremely useful as liquid crystals, and are particularly suitable for liquid crystal displays requiring a wide operating temperature range, low voltage driving and a high response speed.
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- (Fluoroorgano)fluoroboranes and -fluoroborates I: Synthesis and spectroscopic characterization of potassium fluoroaryltrifluoroborates and fluoroaryldifluoroboranes
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A convenient preparation of K[ArBF3] (Ar=2-C6H4F, 3-C6H4F, 4-C6H4F, 2,6-C6H3F2, 3,5-C6H3F2, 2,4,6-C6H2F3, 3,4,5-C6H2F3, 2,3,4,5-C6HF4 and C6F5) is offered and the IR and multinuclear NMR spectra of these salts are reported. Treatment of the trifluoroborate salts with BF3 in chlorocarbon solvents provides an easy synthetic route to the corresponding aryldifluoroboranes ArBF2. The multinuclear NMR spectra of ArBF2 are presented. The electron substituent effect of the [-BF3]--group shows this substituent as one of the strongest σ-electron donors, while its π-electron influence is negligible (σI=-0.32, σR=-0.07).
- Frohn,Franke,Fritzen,Bardin
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p. 127 - 135
(2007/10/03)
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