33064-19-6Relevant academic research and scientific papers
Copper-Promoted Coupling of Propiophenones and Arylhydrazines for the Synthesis of 1,3-Diarylpyrazoles
Dang, Ha V.,Le, Ha V.,Nguyen, Tien M.,Nguyen, Tung T.,Pham, Thuyet L. D.,Phan, Nam T. S.,Tran, Khuong A.
supporting information, p. 801 - 804 (2020/05/19)
Synthesis of 1,3-diarylpyrazoles from commercial substrates and/or simple transformations is still underrated. In this report, we have developed a method for copper-promoted coupling of propiophenones and arylhydrazines. The reactions afforded substituted pyrazoles in the presence of TEMPO oxidant, acetic acid additive, and DMF solvent. A number of functionalities were compatible with reaction conditions, including halogens, methoxy, trifluoromethyl, and nitro groups. An indazole could be obtained if an electron-poor propiophenone was used.
Molybdenum-Mediated One-Pot Synthesis of Pyrazoles from Isoxazoles
Beaumont, Stéphane,Rey, Marine
, p. 3796 - 3804 (2019/10/11)
A one-pot approach for the direct synthesis of substituted pyrazoles from isoxazoles is reported. The process involves isoxazole N-O bond cleavage mediated by a molybdenum complex, in situ hydrolysis of the resulting β-amino enone to the corresponding 1,3-diketone, followed by pyrazole formation in the presence of hydrazine or substituted hydrazine. Good to excellent yields and regioselectivities are obtained with nonsymmetric isoxazoles. By using readily available starting materials, a wide range of substituted pyrazoles may be synthesized by this method.
[3+2]-cycloaddition of in situ generated nitrile imines and acetylene for assembling of 1,3-disubstituted pyrazoles with quantitative deuterium labeling
Voronin, Vladimir V.,Ledovskaya, Maria S.,Gordeev, Evgeniy G.,Rodygin, Konstantin S.,Ananikov, Valentine P.
, p. 3819 - 3828 (2018/04/14)
A novel synthetic methodology for the preparation of 1,3-disubstituted pyrazoles from in situ generated nitrile imines and acetylene is reported. The reactions are performed in a simple two-chamber reactor. One part of the reactor is loaded with hydrazonoyl chloride precursors of active nitrile imine species and a base. The other part is used to generate acetylene from CaC2 and water. Partitioning of the reactants improves the yields of desired pyrazoles up to 99% and simplifies their isolation to a simple procedure of solvent evaporation. The approach requires no complex equipment and utilizes inexpensive, safe, and easy to handle calcium carbide as a starting material. A model deuterium incorporation is carried out according to the developed methodology, producing a series of novel 4,5-dideuteropyrazoles with excellent deuterium enrichment. Theoretical calculations on reaction mechanism and characterization of possible intermediate structures were performed.
Facile synthesis of pyrazoles by iron-catalyzed regioselective cyclization of hydrazone and 1,2-diol under ligand-free conditions
Panda, Niranjan,Ojha, Subhadra
, p. 244 - 251 (2018/03/13)
A facile synthesis of pyrazoles by the cyclization of hydrazones and 1,2-diols was described. In the presence of ferric nitrate, the reaction occurs under neat conditions and makes the use of potassium persulfate to oxidize the diol to α-hydroxy carbaldehyde for the reaction with hydrazones to produce 1,3- and 1,3,5-substituted pyrazoles selectively. The overall regioselective transformation occurs in one-pot under ligand-free, mild conditions even in the presence of air.
Solvent-dependent copper-catalyzed synthesis of pyrazoles under aerobic conditions
Pünner, Florian,Sohtome, Yoshihiro,Sodeoka, Mikiko
supporting information, p. 14093 - 14096 (2016/12/09)
We present a copper-catalyzed oxidative cyclization of β,γ-unsaturated hydrazones, utilizing molecular oxygen as a stoichiometric oxidant. The methodology provides distinct classes of pyrazoles simply by changing the reaction solvent. Tris-substituted pyr
Practical synthesis of pyrazoles via a copper-catalyzed relay oxidation strategy
Tang, Xiaodong,Huang, Liangbin,Yang, Jidan,Xu, Yanli,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 14793 - 14796 (2014/12/11)
Various 1,3- and 1,3,4-substituted pyrazoles are smoothly formed via copper-catalyzed cascade reactions of oxime acetates, amines and aldehydes. This relay oxidative process involves copper-promoted N-O bond cleavage and C-C/C-N/N-N bond formations to furnish pyrazolines, and sequential Cu-O2 system-involved oxidative dehydrogenation of pyrazolines to afford pyrazoles. This transformation provides a novel and versatile approach for the synthesis of pyrazoles, with an inexpensive copper catalyst and green oxidants. It is atom- and step-economical, and possesses a good functional group tolerance, as well as operational simplicity. This journal is
Fe-catalyzed one-pot synthesis of 1,3-Di- and 1,3,5-trisubstituted pyrazoles from hydrazones and vicinal diols
Panda, Niranjan,Jena, Ashis Kumar
, p. 9401 - 9406,6 (2012/12/11)
An iron-catalyzed route for the regioselective synthesis of 1,3- and 1,3,5-substituted pyrazoles from the reaction of diarylhydrazones and vicinal diols has been developed. This method was found to be practical with wide substrate scope.
Fe-catalyzed one-pot synthesis of 1,3-Di- and 1,3,5-trisubstituted pyrazoles from hydrazones and vicinal diols
Panda, Niranjan,Jena, Ashis Kumar
, p. 9401 - 9406 (2013/01/15)
An iron-catalyzed route for the regioselective synthesis of 1,3- and 1,3,5-substituted pyrazoles from the reaction of diarylhydrazones and vicinal diols has been developed. This method was found to be practical with wide substrate scope.
Regioselective microwave-assisted synthesis of substituted pyrazoles from ethynyl ketones
Bagley, Mark C.,Lubinu, M. Caterina,Mason, Christopher
, p. 704 - 708 (2007/12/27)
Reaction of α,β-ethynyl ketones and hydrazine derivatives gives 1,3- and 1,5-disubstituted pyrazoles in good yield. Microwave irradiation in concentrated hydrochloric acid-methanol (1.5% v/v), with concurrent cooling at sub-ambient temperatures or at 120°
