37928-17-9Relevant articles and documents
NHC-palladium-catalyzed ionic liquid-accelerated regioselective oxyarylation of alkynes with diaryl ethers?
Cen, Liying,He, Dan,Jiang, Huanfeng,Li, Jianxiao,Lin, Zidong,Wu, Wanqing
supporting information, p. 1983 - 1988 (2022/04/03)
The first NHC-palladium-catalyzed regioselective oxyarylation of oxime ether in a task-specific ionic liquid via C(sp3)-O and C(sp2)-O bond cleavage of two different types of ethers for the assembly of structurally diverse 4-arylisoxazoles is described. Both the basic ionic liquid [C3NH2mim]Br and NHC-Pd catalyst IPr-Pd-Im-Cl2 played an important role in this transformation. Notably, this new approach provides a practical and straightforward route to access a broad range of privileged 4-arylisoxazole structures with good yields and excellent regioselectivities. Significantly, this catalytic system can be recycled up to eight times without significant loss of catalytic activity.
Highly Site Selective Formal [5+2] and [4+2] Annulations of Isoxazoles with Heterosubstituted Alkynes by Platinum Catalysis: Rapid Access to Functionalized 1,3-Oxazepines and 2,5-Dihydropyridines
Shen, Wen-Bo,Xiao, Xin-Yu,Sun, Qing,Zhou, Bo,Zhu, Xin-Qi,Yan, Juan-Zhu,Lu, Xin,Ye, Long-Wu
supporting information, p. 605 - 609 (2017/01/07)
Platinum-catalyzed formal [5+2] and [4+2] annulations of isoxazoles with heterosubstituted alkynes enabled the atom-economical synthesis of valuable 1,3-oxazepines and 2,5-dihydropyridines, respectively. Importantly, this Pt catalysis not only led to unique reactivity dramatically divergent from that observed under Au catalysis, but also proceeded via unprecedented α-imino platinum carbene intermediates.
A process for the preparation of sodium compound handkerchief auspicious past cloth and wherein the intermediate impurity, preparation method and application
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, (2017/02/24)
The invention provides parecoxib sodium which is prepared by controlling an intermediate impurity and in particular provides a preparation method of a parecoxib sodium compound as well as the intermediate impurity and an application of the parecoxib sodium compound. According to the preparation method provided by the invention, 3-methyl-4,5-diphenyl-4,5-dihydro-isoxazole-5-alcohol is used as an isomer impurity for preparing 5-methyl-3,4-diphenyl-4,5-dihydro-isoxazole-5-alcohol as an intermediate of the parecoxib sodium, the quality of the 3-methyl-4,5-diphenyl-4,5-dihydro-isoxazole-5-alcohol is controlled in the preparation of the parecoxib sodium, specifically, the impurity content is required not to be higher than 0.5 percent, and an important significance is provided for the product quality of the parecoxib sodium; by obtaining the 3-methyl-4,5-diphenyl-4,5-dihydro-isoxazole-5-alcohol as an isomer impurity of the important 5-methyl-3,4-diphenyl-4,5-dihydro-isoxazole-5-alcohol and further studying 3-methyl-4,5-diphenyl-4,5-dihydro-isoxazole-5-alcohol in the aspects of preparation process, detection process and purification process, important quality monitoring significance is provided for the process with the 5-methyl-3,4-diphenyl-4,5-dihydro-isoxazole-5-alcohol as an industrial production raw material.