838-41-5Relevant articles and documents
Convergent Domino Cyclization: Oxidative [3+1+1] Annulation for One-Pot Synthesis of 2-Quinoline-4,5-diaryl-oxazoles from Methyl Azaarenes, Benzoins and NH4OAc
Kong, Hong-Mei,Liang, Fei-Fei,Liu, Kai-Xuan,Shang, Zhi-Hao,Sun, Yuan-Yuan,Yao, Jian-Wen,Yin, Ya-Qing,Zhao, Cong,Zhu, Yan-Ping
supporting information, p. 998 - 1002 (2021/01/18)
An oxidative [3+1+1] convergent domino cyclization is disclosed. This protocol enables to get quinoline, quinoxaline, quinazolin-4(3H)-one and benzo[d]thiazole attached 2,4,5-trisubstituted oxazoles from methyl azaarenes, benzoins, and NH4OAc i
Microwave preparation method of 2, 4-disubstituted oxazole compound
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Paragraph 0014-0015; 0017, (2020/11/25)
The invention discloses a microwave preparation method of a 2, 4-disubstituted oxazole compound. The method comprises the following steps: carrying out heating reflux reaction on substituted carboxylic acid and thionyl chloride, after the reaction is finished, carrying out rotary evaporation to remove excessive thionyl chloride to obtain yellow transparent liquid substituted acyl chloride, and then adding dichloromethane to dilute for later use; dropwise adding substituted acyl chloride into ammonia water while stirring under an ice bath condition, removing the ice bath after the acyl chlorideis dropwise added, stirring at room temperature until a large amount of white solids appear in the solution, carrying out suction filtration after the reaction is finished, and drying to obtain substituted amide. Substituted amide, dichloromethane, triethylamine and an alpha-bromocarbonyl compound are loaded into a pressure reaction tank designed by CEM. The mixture is irradiated in a CEM DISCOVER 2.0 annular focusing single-mode microwave synthesizer. The mixture is cooled to room temperature by passing compressed air through a microwave chamber. The target compound is filtered after cooling, and the crude solid recrystallized with ethanol to obtain the 2, 4-disubstituted oxazole compound.
A novel synthetic method of 2,4-disubstituted oxazoles using carboxylic acid-derived Bu2Sn[OC(O)R]2
Yoneyama, Hiroki,Oka, Naoki,Usami, Yoshihide,Harusawa, Shinya
supporting information, (2020/05/21)
A novel synthetic method for the preparation of 2,4-disubstituted oxazoles was developed, entailing the reaction of dibutyltin diacylates Bu2Sn[OC(O)R]2 with 1-substituted acetylenes and TMSN3 to afford a range of 2,4-disu
Divergent Palladium-Catalyzed Tandem Reaction of Cyanomethyl Benzoates with Arylboronic Acids: Synthesis of Oxazoles and Isocoumarins
Chen, Jiuxi,Chen, Zhongyan,Dai, Ling,Shao, Yinlin,Xiong, Wenzhang,Xu, Tong,Yu, Shuling
supporting information, (2020/04/15)
A palladium-catalyzed tandem reaction of cyanomethyl benzoates with arylboronic acids has been achieved. Substitution at the 2-position of cyanomethyl benzoates was found to be crucial for the selective synthesis of oxazoles and isocoumarins. Cyanomethyl
Radical cascade synthesis of azoles: via tandem hydrogen atom transfer
Chen, Andrew D.,Herbort, James H.,Mustafa, Darsheed N.,Nagib, David A.,Nakafuku, Kohki M.,Wappes, Ethan A.
, p. 2479 - 2486 (2020/03/19)
A radical cascade strategy for the modular synthesis of five-membered heteroarenes (e.g. oxazoles, imidazoles) from feedstock reagents (e.g. alcohols, amines, nitriles) has been developed. This double C-H oxidation is enabled by in situ generated imidate
PdII-Catalyzed Regio- and Enantioselective Oxidative C?H/C?H Cross-Coupling Reaction between Ferrocenes and Azoles
Cai, Zhong-Jian,Liu, Chen-Xu,Gu, Qing,Zheng, Chao,You, Shu-Li
supporting information, p. 2149 - 2153 (2019/01/24)
Asymmetric C?H bond functionalization reaction is one of the most efficient and straightforward methods for the synthesis of optically active molecules. Herein we disclose an asymmetric C?H/C?H cross-coupling reaction of ferrocenes with azoles such as oxazoles and thiazoles. Palladium(II)/monoprotected amino acid (MPAA) catalytic system which exhibits excellent reactivity and regioselectivity for oxazoles and thiazoles. This method offers a powerful strategy for constructing planar chiral ferrocenes. Mechanistic studies suggest that the C?H bond cleavage of azoles is likely proceeding through a SEAr process and may not be a turnover limiting step.
Divergent Conversion of N-Acyl-isoxazol-5(2 H)-ones to Oxazoles and 1,3-Oxazin-6-ones Using Photoredox Catalysis
Mei, Mingjing,Anand, Devireddy,Zhou, Lei
supporting information, p. 3548 - 3553 (2019/05/24)
The fragmentation of N-acyl-isoxazol-5-ones using visible light photoredox catalysis has been disclosed. The catalyst-controlled divergent mechanisms, namely the oxidative and reductive quenching catalytic cycle, are utilized. Various oxazoles and 1,3-oxazin-6-ones are selectively obtained from the same isoxazol-5-one skeleton under mild conditions.
Lewis acid-mediated defluorinative [3+2] cycloaddition/aromatization cascade of 2,2-difluoroethanol systems with nitriles
Hsieh, Min-Tsang,Lee, Kuo-Hsiung,Kuo, Sheng-Chu,Lin, Hui-Chang
, p. 1605 - 1610 (2018/03/05)
The properties of C?F bonds, including high thermal and chemical stability, make derivatization of organic fluorine-containing compounds by the activation of the C?F bond and subsequent functionalization quite challenging. We herein report a Lewis acid-mediated defluorinative cycloaddition/aromatization cascade of 2,2-difluoroethanols with nitriles as a novel synthetic method for the preparation of 2,4,5-trisubstituted oxazoles. This reaction, which involves cleavage of two C?F bonds and the consecutive formation of C?O and C?N bonds in a one-pot fashion, features a broad substrate scope and moderate to high reaction yields. Mechanistic studies revealed that the reaction is initiated by the Lewis acid-mediated ring closure of the 2,2-difluoroethanol to produce the fluoroepoxide intermediate. (Figure presented.).
Radical C-H Arylation of Oxazoles with Aryl Iodides: Dppf as an Electron-Transfer Mediator for Cs2CO3
Guo, Zhengwei,Li, Man,Mou, Xue-Qing,He, Gang,Xue, Xiao-Song,Chen, Gong
supporting information, p. 1684 - 1687 (2018/03/23)
A radical C-H arylation reaction of oxazoles with (hetero)aryl iodides using Cs2CO3 as base/electron donor and 1,1′-bis(diphenylphosphino) ferrocene (dppf) as a catalytic SET mediator is reported. The overall reaction likely follows the general base-promoted homolytic aromatic substitution mechanism through a radical-chain pathway. DFT calculations suggest that dppf forms a complex with CsCO3-, enhancing its SET reducing ability to generate an aryl radical from ArI.
Metal-free syntheses of oxazoles and their analogues based on λ3-iodane-mediated cycloisomerization/functionalization reactions or [2+2+1] cycloaddition type reactions
Saito, Akio
, p. 84 - 98 (2017/04/17)
As a metal-free construction of oxazoles and furans concomitant with the introduction of oxygen functional groups or fluorine atoms into the side chains, we have developed λ3-iodane-mediated cycloisomerization/functionalization reactions of propargyl compounds. In these reactions, aryl- λ3-iodane ArI(X)Y works not only as a donor of heteroatomic functional groups but also as an activator of carbon-carbon triple bonds. Therefore, this methodology is not required any transition metal catalysts, which are frequently used in previous methods. Furthermore, this methodology can be extended to λ3-iodane-mediated [2+2+1] cycloaddition type reactions of alkynes, nitriles and heteroatoms for metal-free formation of oxazoles and imidazoles.
