Facile synthesis of pyrazoles by iron-catalyzed regioselective cyclization of hydrazone and 1,2-diol under ligand-free conditions
作者:Niranjan Panda、Subhadra Ojha
DOI:10.1016/j.jorganchem.2018.02.043
日期:2018.4
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
Fe-Catalyzed One-Pot Synthesis of 1,3-Di- and 1,3,5-Trisubstituted Pyrazoles from Hydrazones and Vicinal Diols
作者:Niranjan Panda、Ashis Kumar Jena
DOI:10.1021/jo301770k
日期:2012.10.19
An iron-catalyzed route for the regioselectivesynthesis of 1,3- and 1,3,5-substituted pyrazolesfrom the reaction of diarylhydrazones and vicinal diols has been developed. This method was found to be practical with wide substrate scope.
Primary Vinyl Ethers as Acetylene Surrogate: A Flexible Tool for Deuterium-Labeled Pyrazole Synthesis
作者:Maria S. Ledovskaya、Vladimir V. Voronin、Mikhail V. Polynski、Andrey N. Lebedev、Valentine P. Ananikov
DOI:10.1002/ejoc.202000674
日期:2020.8.9
A novel synthetic path to 1,3‐disubstituted pyrazoles, 4,5‐dideuteropyrazoles and 5‐deuteropyrazoles based on the interaction of the readily available vinyl ethers and in situ generated nitrile imines was developed. The joint experimental and computational study clarified the mechanism of the process and allowed us to propose a convenient access to regioselectively deuterated pyrazoles.
The cycloaddition of N,N-diethyl-1,3-butadienylamine with some diarylnitrilimines was investigated. 1,3-diaryl-4-vinylpyrazoles, (1,3-diaryl-2-pyrazolin-5-yl)acetaldehydes, 1,3-diaryl-4-(1,3-diaryl-2-pyrazolin-5-yl)pyrazoles, and 1,3-diarylpyrazoles were obtained.
Copper-catalyzed reactions of α,β-unsaturated <i>N</i>-tosylhydrazones with diaryliodonium salts to construct <i>N</i>-arylpyrazoles and diaryl sulfones
作者:Lian-Mei Chen、Chuang Zhou、Jing Li、Jun Li、Xiao-Qiang Guo、Tai-Ran Kang
DOI:10.1039/d2ob01338j
日期:——
Herein, an economical copper-catalyzed reaction of α,β-unsaturated N-tosylhydrazones with diaryliodoniumsalts to construct both N-arylpyrazoles and diaryl sulfones has been developed. Both the p-toluenesulfonyl anion and the 3-arylpyrazole intermediates were formed in situ from N-tosylhydrazones. Subsequently, the former reacted rapidly with diaryliodoniumsalts to give diaryl sulfones and aryl iodide