7064-04-2Relevant academic research and scientific papers
Acyclic nitronate olefin cycloaddition (ANOC): regio- And stereospecific synthesis of isoxazolines
Ma, Liang,Kou, Luyao,Jin, Feng,Cheng, Xionglve,Tao, Suyan,Jiang, Gangzhong,Bao, Xiaoguang,Wan, Xiaobing
, p. 774 - 779 (2021/01/28)
We report the first demonstrations of intra- and intermolecular acyclic nitronate olefin cycloaddition (ANOC) reactions that enable the highly efficient syntheses of isoxazolines bearing various functional groups. This general approach to accessing γ-lactone fused isoxazolines was hitherto unprecedented. The room temperature transformations reported herein exhibit wide substrate scopes, as evidenced by more than 70 examples, including the generation of five tricyclic isoxazolines. The robustness of this methodology was confirmed by a series of trials that afforded highly functionalized isoxazolines. Both experimental results and density functional theory calculations indicate that these transformations proceed via the in situ formation of acyclic nitronates together with concerted [3+2] cycloaddition and tert-butyloxy group elimination processes to give regio- and stereospecificity. This journal is
Method for preparing isoxazoline
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Paragraph 0043-046, (2020/12/15)
The invention relates to a method for preparing isoxazoline, which comprises the steps of reacting olefin, a diazo compound and tert-butyl nitrite in an organic solvent at the temperature of 25-50 DEGC under the action of a Lewis acid catalyst to obtain isoxazoline after complete reaction. Lewis acid is used as a catalyst for synthesizing isoxazoline, reaction conditions are mild and can be carried out under the condition that the temperature is as low as the room temperature, use of transition metal is avoided, and the product yield is high.
Oxidize Amines to Nitrile Oxides: One Type of Amine Oxidation and Its Application to Directly Construct Isoxazoles and Isoxazolines
Zhang, Xiao-Wei,He, Xiao-Lin,Yan, Nan,Zheng, Hong-Xing,Hu, Xiang-Guo
, p. 15726 - 15735 (2020/11/30)
A facile oxidative heterocyclization of commercially available amines and tert-butyl nitrite with alkynes or alkenes leading to isoxazoles or isoxazolines is described. The unprecedented strategy of the oxidation of an amine directly to a nitrile oxide was used in this cyclization process. This reaction is highly efficient, regiospecific, operationally simple, mild, and tolerant of a variety of functional groups. Control experiments support a nitrile oxide intermediate mechanism for this novel class of oxidative cyclization reactions. Moreover, synthetic applications toward bioactive molecular skeletons and the late-stage modification of drugs were realized.
Synthesis of Isoxazolines and Oxazines by Electrochemical Intermolecular [2 + 1 + n] Annulation: Diazo Compounds Act as Radical Acceptors
Xiong, Mingteng,Liang, Xiao,Gao, Zhan,Lei, Aiwen,Pan, Yuanjiang
supporting information, p. 9300 - 9305 (2019/11/20)
Reported herein is an unprecedented synthesis of isoxazolines and oxazines through electrochemical intermolecular annulation of alkenes with tert-butyl nitrite, in which diazo compounds serve as radical acceptors. Notably, [2 + 1 + 2] and [2 + 1 + 3] annulations occur when styrenes and allylbenzenes are used as substrates, respectively. The latter reaction undergoes group migration to form more stable radical, manifesting radical route instead of conventional 1,3-dipolar cycloaddition occurs. Moreover, scale-up experiments suggest the potential application value of these transformations in industry.
Harnessing the TEMPO-Catalyzed Aerobic Oxidation for Machetti-De Sarlo Reaction toward Sustainable Synthesis of Isoxazole Libraries
Vadivelu, Murugan,Sampath, Sugirdha,Muthu, Kesavan,Karthikeyan, Kesavan,Praveen, Chandrasekar
, p. 13636 - 13645 (2019/10/17)
A practical synthesis of isoxazole/isoxazoline derivatives via Machetti-De Sarlo reaction under sustainable conditions has been accomplished. This protocol involves the use of readily available 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) to catalyze the
Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions
Gagnot, Glwadys,Hervin, Vincent,Coutant, Eloi P.,Desmons, Sarah,Baatallah, Racha,Monnot, Victor,Janin, Yves L.
supporting information, p. 2846 - 2852 (2018/11/27)
We report here on the use of ethyl nitroacetate as a glycine template to produce α-amino esters. This started with a study of its condensation with various arylacetals to give ethyl 3-aryl-2-nitroacrylates followed by a reduction (NaBH4 and then zinc/HCl) into α-amino esters. The scope of this method was explored as well as an alternative with arylacylals instead. We also focused on various [2 + 3] cycloadditions, one leading to a spiroacetal, which led to the undesired ethyl 5-(benzamidomethyl)isoxazole-3-carboxylate. The addition of ethyl nitroacetate on a 5-methylene-4,5-dihydrooxazole using cerium(IV) ammonium nitrate was also explored and the synthesis of other oxazole-bearing α-amino esters was achieved using gold(I) chemistry.
Method for preparing isoxazoline derivative
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Paragraph 0023, (2017/09/13)
The invention discloses a method for preparing an isoxazoline derivative. The method comprises the following steps: by taking an olefin derivative, a diazonium derivative and tert-butyl nitrite as reaction substrates, and a copper compound as a catalyst, in the presence of alkali, coupling metal carbine with a free radical, and further performing serial cyclization reaction, thereby obtaining the isoxazoline derivative. The invention designs a method for very conveniently synthesizing the isoxazoline derivative from cheap and easily obtained raw materials with a cheap metal copper compound as a catalyst in a sealed tube system directly under gentle reaction conditions. By adopting the method, the problems that in a conventional synthesis method, a great amount of oxidants are used, precious metals are adopted as catalysts and harsh experiment conditions such as anhydrous and anaerobic reaction are implemented are avoided, the reaction is simple and feasible, later treatment is simple, and potential industrial application values can be achieved.
Coupling Reaction of Cu-Based Carbene and Nitroso Radical: A Tandem Reaction to Construct Isoxazolines
Chen, Rongxiang,Zhao, Yanwei,Fang, Shangwen,Long, Wenhao,Sun, Hongmei,Wan, Xiaobing
supporting information, p. 5896 - 5899 (2017/11/10)
In this letter, an unprecedented cross-coupling reaction between copper carbene and nitroso radical has been developed. This radical-carbene coupling reaction (RCC reaction) offers a novel approach for the preparation of various isoxazolines, which features the construction of C-C, C-O, and C=N bonds in a one-pot process. The synthetic utility of our method is further enhanced by its mild reaction conditions, wide substrate scope, and simple procedures.
Effect of aqueous polyethylene glycol on 1,3-dipolar cycloaddition of benzoylnitromethane/ethyl 2-nitroacetate with dipolarophiles: Green synthesis of isoxazoles and isoxazolines
Chary, R. Gangadhara,Reddy, G. Rajeshwar,Ganesh,Prasad, K. Vara,Raghunadh, Akula,Krishna,Mukherjee, Soumita,Pal, Manojit
supporting information, p. 160 - 164 (2014/03/21)
A 1:1 mixture of water-polyethylene glycol (PEG) facilitated the 1,3-dipolar cycloaddition of benzoylnitromethane/ethyl 2-nitroacetate with terminal alkynes or alkenes leading to isoxazoles or isoxazolines under green conditions. The methodology is free f
Acid-base-catalysed condensation reaction in water: Isoxazolines and isoxazoles from nitroacetates and dipolarophiles
Trogu, Elena,Vinattieri, Claudia,De Sarlo, Francesco,MacHetti, Fabrizio
experimental part, p. 2081 - 2093 (2012/03/26)
Base-catalysed condensation reactions of nitroacetic esters with dipolarophiles to give isoxazole derivatives proceed faster, and often with higher yields, in the presence of water than in organic solvents such as chloroform. Kinetic profiles show that in
