33064-19-6Relevant articles and documents
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.
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
, 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