- Mild and Robust Stille Reactions in Water using Parts Per Million Levels of a Triphenylphosphine-Based Palladacycle
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An inexpensive and new triphenylphosphine-based palladacycle has been developed as a pre-catalyst, leading to highly effective Stille cross-coupling reactions in water under mild reaction conditions. Only 500–1000 ppm of Pd suffices for couplings involving a variety of aryl/heteroaryl halides with aryl/hetaryl stannanes. Several drug intermediates can be prepared using this catalyst in aqueous nanoreactors formed by 2 wt % Brij-30 in water.
- Takale, Balaram S.,Thakore, Ruchita R.,Casotti, Gianluca,Li, Xaiohan,Gallou, Fabrice,Lipshutz, Bruce H.
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supporting information
p. 4158 - 4163
(2021/02/01)
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- Synthesis of new adamantyl-imine palladium(II) complexes and their application in Mizoroki-Heck and Suzuki-Miyaura C[sbnd]C cross-coupling reactions
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Improving carbon–carbon cross-coupling reactions is an ongoing process and finding the most versatile and stable catalyst precursors has been of great interest. Ligand design has been proven to be important since it is responsible for providing electron density and steric saturation around the metal centre, thus contributing towards the stereo-electronic properties. The adamantyl moiety has been used to generate highly bulky and electron-rich ligands for application in palladium-catalysed cross-coupling reactions. Accordingly, we have prepared some Schiff-base adamantyl ligands (L1-L3) and complexed them with [PdCl2(MeCN)2] to afford the (pre)catalysts C1-C3, which were successfully applied in Mizoroki-Heck and Suzuki-Miyaura carbon–carbon cross-coupling reactions. The cross-coupling reaction products were obtained in good yields using 0.5 mol % Pd catalyst loading. C2 and C3 showed remarkable activity in the Mizoroki-Heck coupling reactions involving substrates with substituents on the olefin and aryl halide (including 4-Cl, 4-CH3, -CO2Me and -CO2Et). We also, observed that the Suzuki-Miyaura cross-coupling system was active towards challenging activated and deactivated aryl chlorides, with to up 70% conversions recorded. The mercury poisoning tests conducted revealed that the catalysts act as homogenous molecular active species in the Mizoroki-Heck reactions and act as both homogenous and heterogeneous catalysts in the Suzuki-Miyaura cross-coupling reactions.
- Makhubela, Banothile C. E.,Matsheku, Asanda C.,Maumela, Munaka C.
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- Synthetic method for bifenazate
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The invention relates to a synthetic method for bifenazate. The method comprises the following specific synthetic sections: step 1, performing nitration: mixing a 4-hydroxybiphenyl solution and a toluene solution under stirring for a reaction, and adding a HNO3 solution dropwise for a reaction to obtain a nitration reaction solution; step 2, performing methylation: mixing the nitration reaction solution and anhydrous sodium carbonate powder for a reaction, and adding a dimethyl carbonate solution dropwise for a reaction to obtain a methylation reaction solution; step 3, performing hydrogenation: throwing the methylation reaction solution, hydrogen gas, and Raney nickel into a reaction kettle for a reaction to obtain a hydrogenation reaction liquid; step 4, performing hydrazination: performing a primary hydrazination reaction, performing a secondary hydrazination reaction, performing filter pressing, performing a tertiary hydrazination reaction, and performing secondary filter pressingto obtain a condensation reaction liquid; step 5, performing condensation: mixing a third hydrazine compound, an ethyl acetate solution and an isopropyl chloroformate solution for a reaction to obtaina bifenazate mixed liquid; and step 6, performing purification: performing desolvation, performing crystallization, performing centrifugation, performing washing, performing secondary centrifugation,and performing drying to obtain the finished bifenazate. The method provided by the invention has the effect of improving purity of the bifenazate product.
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- Sulfonamide compound and medical applications thereof
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The invention discloses a compound containing a sulfonamide structure, a preparation method thereof, and medical applications of the compound, and more specifically discloses the compound with a structure represented by formula I, and a pharmaceutically acceptable salt or a prodrug or a solvate thereof. The compound is used for tumor treatment through inhibiting ATP-citrate lyase.
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Paragraph 0044; 0046; 0048
(2019/02/13)
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- Compounding method for acaricide bifenazate intermediate 3-nitro-4-methoxyphenyl
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The invention relates to a compounding method for an acaricide bifenazate intermediate 3-nitro-4-methoxyphenyl and belongs to the field of pesticide preparation. The compounding method is characterized by acquiring 3-nitro-4-methoxyphenyl from the reaction of 4-halogenated-2-nitroanisole and benzene halide under the action of catalyst. The reaction process is as follows: 1) uniformly mixing 4-halogenated-2-nitroanisole, benzene halide, catalyst and solvent A under a shielding gas condition, rising temperature to 130-150 DEG C, controlling pressure to 7-12 barometric pressures, reacting for 20-35h and ending; 2) performing vacuum filtration on the system and removing solid insoluble substances, thereby acquiring a filtrate a; pouring the filtrate a into 3-5 times of water, adding a solventB for extracting, layering and then using a drying agent for drying an organic phase, and concentrating, thereby acquiring a solid; re-crystallizing the solid with a solvent C, thereby acquiring 3-nitro-4-methoxyphenyl. The compounding method has the advantages of few steps, higher yield and more convenient operation.
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Paragraph 0028-0049
(2019/02/10)
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- Method for nitrating aromatic compound by using nitrate under the action of auxiliary agent
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The invention discloses a method for nitrating an aromatic compound by using a nitrate under the action of an auxiliary agent, and provides an aromatic nitro compound preparation method, which comprises: in the presence of an external action and an auxiliary agent, carrying out a nitrating reaction on an aromatic compound and a metal nitrate or a hydrate thereof to obtain the aromatic nitro compound, wherein the external action can cause the physical and/or chemical property change of a substance, the auxiliary agent is a substance having water absorbing ability, the external action can be mechanical force or heating, and the mechanical force can be any one selected from compression, shearing, impacting, friction, stretching, bending and vibration. According to the present invention, the method does not require any solvents so as to avoid the generation of the waste liquid; the acidic substance is not used, such that the treatment is simple after the reaction is completed, and the equipment is not damaged; the added auxiliary agent can be theoretically recycled; and the method has extremely high conversion rate and extremely high selectivity, and can be used for the nitration of conventional aromatic compounds.
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Paragraph 0043-0052
(2018/09/11)
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- Mechanical force under the action of the nitration of aromatic compounds of nitrate method (by machine translation)
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The invention discloses a mechanical force under the action of the nitration of aromatic compounds of nitrate method. The invention provides a method for preparing aromatic nitro compounds, comprising the following steps: under the action of mechanical force, aromatic compound with a metal nitrate or its hydrate by the nitration reaction, to obtain the aromatic nitro compound; the mechanical fastener is machinery offers can cause material physical and/or chemical nature of the change of the external force. The mechanical force can be compression, shear, impact, friction, tensile, bending and vibration of any kind. The invention has the following advantages: without the use of any solvent, thereby avoiding the waste liquid produced; and without the use of the acidic substance, the reaction is complete after treatment is simple, without any damage to the apparatus; a very high conversion and selectivity, can be applied to the nitration of conventional aromatic compound. (by machine translation)
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Paragraph 0036-0047; 0052; 0053
(2018/09/11)
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- Direct nitration method of electron-enriched aromatic hydrocarbons
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The invention discloses a direct nitration method of electron-enriched aromatic hydrocarbons, and belongs to the field of organic synthesis. The direct nitration method is a novel green free radical nitration method; aromatic hydrocarbons are taken as raw materials, acetonitrile, dichloromethane, chloroform, or acetone is taken as a reaction solvent, at room temperature conditions, the raw materials and green nitration reagent tert-butyl nitrite (TBN) are subjected to free radical nitration so as to obtain nitro-aromatic compounds. According to the direct nitration method, no metal is adoptedin reaction, tert-butyl nitrite is directly adopted in nitration reaction. Electron-donating groups such as OMe are introduced, the electron density of aromatic compounds is increased, the nitration reaction possibility is increased. The using amount of tert-butyl nitrite is reduced; only a product and tert-butyl alcohol are generated, environment pollution is reduced. The direct nitration methodis promising in application prospect in the field of nitro-aromatic compound synthesis, green nitration is realized, and a novel idea is provided for large-scale industrialized nitro-aromatic compoundproduction.
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Paragraph 0057-0059
(2018/10/02)
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- Efficient and practical cross-coupling of arenediazonium tetrafluoroborate salts with boronic acids catalyzed by palladium(0)/barium carbonate
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The cross-coupling reaction of arenediazonium tetrafluoroborate salts with boronic acids catalyzed by the unusual palladium(0)/barium carbonate catalyst is described as an extremely practical and highly efficient alternative to classical homogeneous conditions. Reactions are conducted under mild conditions at room temperature without any base and ligand. The opportunity of preparing unsymmetrical terphenyls in a one-pot process is also demonstrated. Finally, the power of this methodology is highlighted by the synthesis of Bifenazate.
- Felpin, Francois-Xavier,Fouquet, Eric
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scheme or table
p. 863 - 868
(2009/05/07)
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- The discovery of bifenazate, a novel carbazate acaricide
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A history of the discovery of the novel carbazate acaricide, bifenazate, is outlined. When a novel ortho-biphenyl substituted hydrazide compound showed acaricidal activity in the pesticide discovery screen, a small number of analogs were made to confirm and explore acaricidal effects. An ortho-biphenylcarbazate analog gave significantly greater acaricidal activity. Thereafter, several hundred structurally-diverse biphenylsubstituted carbazate analogs were synthesized and evaluated in a bioassay with the two-spotted spider mite (Tetranychus urticae Koch) in order to optimize the acaricidal activity. As a result of the optimization process, bifenazate, the analog with a methoxybiphenyl substituent to the terminal nitrogen atom of isopropyl carbazate, was selected for development and registration.
- Dekeyser, Mark A.,McDonald, Paul T.,Angle Jr., Gilbert W.
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p. 702 - 704
(2007/10/03)
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