105-36-2Relevant articles and documents
In situ generation of nitrile oxides from copper carbene and tert -butyl nitrite: Synthesis of fully substituted isoxazoles
Chen, Rongxiang,Ogunlana, Abosede Adejoke,Fang, Shangwen,Long, Wenhao,Sun, Hongmei,Bao, Xiaoguang,Wan, Xiaobing
, p. 4683 - 4687 (2018)
Herein, we present a novel [3 + 2] cycloaddition reaction of β-keto esters with nitrile oxides, which were generated in situ from copper carbene and tert-butyl nitrite. This three-component reaction provides new methodology for the direct synthesis of fully substituted isoxazole derivatives, featuring mild reaction conditions, readily accessible starting materials and simple operation. The experimental studies and DFT calculations suggest that the reaction starts with the generation of the key intermediate nitrile oxides, followed by a [3 + 2] cycloaddition reaction of β-keto esters to give the final isoxazole products.
Analyse structurale des derives fonctionnels des acides carboxyliques Partie III. Acetate d'ethyle et derives α-halogenes
Maury, Catherine,Petrissans, Jean
, p. 221 - 232 (1991)
Methylene bending mode analysis of ethyl esters of acetic and haloacetic acids XCH2CO2C2H5 where X=H(I), F(II), Cl(III), Br(IV) and I(V) reveals that in the dissolved state (CCl4) these compounds have conformations induced by rotating motion of the XCH2 and C2H5 groups ( (II), (III) and (IV) ) or by C2H5 group rotation exclusively ( (I) and (V) ).In the last case, (I) exists in gauche and anti conformations while (V) occurs in gauche-gauche and gauche-anti conformations.A theoretical study of compounds (I), (II) and (III) by the PCILO method and Onsager formalism leads to the following conclusions.The conformers of (I) have a dihedral angle (H3)C-C(H2)-O-C of 70 deg (gauche conformer) and 180 deg (anti conformer).For (II) and (III), there are four stable conformers whose dihedral angles φ3=(H3)C-C(H2)-O-C and θ=X-C-C=O values are in agreement with C2H5 and CH2X group orientations found in experimental analysis.
Activation of alkyl halides via a silver-catalyzed carbene insertion process
Dias, H. V. Rasika,Browning, R. Greg,Polach, Sharon A.,Diyabalanage, Himashinie V. K.,Lovely, Carl J.
, p. 9270 - 9271 (2003)
The silver complex [HB(3,5-(CF3)2Pz)3]Ag(THF) featuring a highly fluorinated tris(pyrazolyl)borate ligand catalyzes the formation of aliphatic carbon-halogen bond activation products under remarkably mild conditions. For example, the reaction between CHCl3 and ethyl diazoacetate (EDA) at room temperature in the presence of the silver catalyst afforded HClC(CO2Et)CCl2H in 60% yield. The presence of β-hydrogens on the alkyl halide leads to net hydrogen halide addition to the carbene and an alkene. Copyright
A method for esterification reaction rate prediction of aliphatic monocarboxylic acids with primary alcohols in 1,4-dioxane based on two parametrical taft equation
Vojtko, Jan,Tomcik, Peter
, p. 189 - 196 (2014)
Esterification reaction rates of aliphatic monocarboxylic acids with primary alcohols in 1,4-dioxane as inert solvent were investigated. Acids were esterified with 1-propanol and alcohols with acetic acid as model reactants at a constant temperature of 60°C, at a fixed ionic strength and pH in a batch reactor with a constant volume. For evaluation of reaction rates, an exact kinetic equation for the equilibrium reaction was applied. Under these conditions and for low reactants, concentrations reaction rate depends only on the structure of reactants and, therefore, can be predicted by a correlation equation with two Taft coefficients (inductive and steric effects). From these equations, it is possible to estimate the esterification reaction rate constant for other acid-alcohol pairs. This methodology may also be suitable for other kinetic systems measured under comparable experimental conditions.
Visible-Light-Assisted Gold-Catalyzed Fluoroarylation of Allenoates
Feng, Chao,Tang, Hai-Jun,Zhang, Xinggui,Zhang, Yu-Feng
, p. 5242 - 5247 (2020)
A strategically novel synthetic method for the fluoroarylation of allenic ester was developed that enables the expedient construction of a host of β-fluoroalkyl-containing cinnamate derivatives. The reaction proceeds through visible-light-promoted gold redox catalysis, occurs smoothly under very mild reaction conditions, accommodates a large variety of functional groups, and more importantly allows the incorporation of fluorine and aryl groups with excellent regio- and stereoselectivity. The concomitant activation mode for both the allene motif and the hydrogen fluoride is key for the success of the reaction.
In Situ Generation of Oxazole Ylide and Interception with Sulfonamide: Construction of Amidines Using Two Diazo Molecules
Chen, Jijun,Long, Wenhao,Zhao, Yanwei,Li, Haiyan,Zheng, Yonggao,Lian, Pengcheng,Wan, Xiaobing
, p. 857 - 865 (2018)
A novel generation of oxazole ylide and interception with sulfonamide have been well developed to construct fully substituted amidines. This copper-catalyzed four-component reaction incorporates two diazo molecules to target amidines and shows broad substrate scope, excellent functional groups tolerance and good to excellent yields.
Facile One Pot Multi-Component Solvent-Free Synthesis of 2,4,5-Trisubstituted Imidazoles Using “Green” and Expeditious Ionic Liquid Catalyst under Microwave Irradiation
Sonyanaik,Ashok,Rambabu,Ravi,Kurumanna,Madhu,Sakram
, p. 537 - 540 (2018)
Acetic acid functionalized poly(4-vinylpyridinium) bromide is a highly efficient and recyclable catalyst for the construction of 2,4,5-trisubstituted imidazole derivatives by a three-component condensation of benzyl with various aldehydes and ammonium acetate under solvent free conditions. The microwave initiated process leads to analytically pure compounds within 2–5 min. The advantages of this “green” methodology are cost-effectiveness, simple procedure, low energy consumption, no involvement of organic solvents, safe operation, clean reaction profile, high yields, and recyclability of the catalyst.
Synthesis process of thiazole medical intermediate
-
Paragraph 0013, (2021/06/09)
The invention discloses a synthesis process of thiazole medical intermediate.The synthesis process comprises the following steps: step 1, mixing ethyl pyruvate and dichloromethane of which the volume is 2 times that of the ethyl pyruvate at room temperature, adding an obtained mixture into a reactor, starting stirring, and keeping the temperature of a system at about 20 DEG C; step 2, starting to dropwise add a dichloromethane solution of bromine, controlling the temperature to enable the system to be about 20-30 DEG C, sealing the reactor, and introducing a strong alkali solution to absorb acid gas HBr; and step 3, after dropwise adding is completed, closing a cold well, performing stirring at normal temperature for about 2 hours until the color of the reaction liquid gradually becomes light yellow to light brown, monitoring that no raw material exists through TLC, and concentrating the obtained reaction liquid. According to the synthesis process of the thiazole medical intermediate, by introducing the defoaming agent n-hexane, generated gas foam can be quickly dissolved out and released from the solvent, and the phenomenon of one-time flushing is avoided; and by introducing the n-hexane solvent, solids can be effectively separated out at low temperature, the impurity content can be controlled to be about 1%, the purification difficulty is greatly reduced, and crystallization is facilitated.
Acridine Orange Hemi(Zinc Chloride) Salt as a Lewis Acid-Photoredox Hybrid Catalyst for the Generation of α-Carbonyl Radicals
Das, Sanju,De Sarkar, Suman,Mandal, Tanumoy
supporting information, (2021/12/10)
A readily accessible organic-inorganic hybrid catalyst is reported for the reductive fragmentation of α-halocarbonyl compounds. The robust hybrid catalyst is a self-stabilizing combination of ZnCl2 Lewis acid and acridine orange as the photoactive organic dye. Mechanistic specifics of this hybrid catalyst have been studied in detail using both photophysical and electrochemical experiments. A systematic study enabled the discovery of the appropriate Lewis acid for the effective LUMO stabilization of α-halocarbonyl compounds and thereby lowering of reduction potential within the range of a standard organic dye. This strategy resolves the issues like dehalogenative hydrogenation or homo-coupling of alkyl radicals by guiding the photoredox cycle through an oxidative quenching pathway. The cooperativity between the photoactive organic dye and the Lewis acid counterparts empowers functionalization with a wide range of coupling partners through efficient and controlled generation of alkyl radicals and serves as an appropriate alternative to the expensive late transition metal-based photocatalysts. To demonstrate the application potential of this cooperative catalytic system, four different synthetic transformations of α-carbonyl bromides were explored with broad substrate scopes.
Synthesis method of ethyl 3-hydroxyhexanoate
-
Paragraph 0017; 0019; 0021; 0023; 0025; 0027; 0029; 0031, (2020/02/27)
The invention discloses a synthesis method of ethyl 3-hydroxyhexanoate. The method is characterized by comprising the following steps: reacting bromine with acetic acid to prepare bromoacetic acid; reacting the bromoacetic acid with ethanol in the presence of sulfuric acid to generate ethyl bromoacetate; adding 500kg of dichloromethane and 140kg of n-butyraldehyde into a reaction kettle; adding acatalyst, heating to reflux, dropwise adding 250kg of the ethyl bromoacetate serving as a product obtained in the previous step, controlling the dropwise adding speed, controlling the adding to be completed within 3 hours in a reflux state, preserving heat for 2 hours, cooling to room temperature, washing to neutrality, transferring into a rectifying tower, and rectifying to obtain a qualified product, namely the ethyl 3-hydroxyhexanoate.
