20147-63-1Relevant academic research and scientific papers
Primary Vinyl Ethers as Acetylene Surrogate: A Flexible Tool for Deuterium-Labeled Pyrazole Synthesis
Ananikov, Valentine P.,Lebedev, Andrey N.,Ledovskaya, Maria S.,Polynski, Mikhail V.,Voronin, Vladimir V.
, (2020/07/24)
A novel synthetic path to 1,3-disubstituted pyrazoles and their deuterated derivatives was developed. It is based on the reaction of vinyl ethers with hydrazonoyl chlorides in the presence of triethylamine. The reaction mechanism, clarified by the joint experimental and computational study, involves 1,3-dipolar cycloaddition of the in situ generated nitrile imines to vinyl ethers and subsequent cleavage of alcohol from the formed alkoxypyrazoline. The results highlight the possibility of using vinyl ethers as acetylene surrogate and provide a novel access to pyrazoles, 4,5-dideuteropyrazoles and their regioselectively labeled derivatives, 5-deuteropyrazoles.
[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.
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.
The Cycloaddition of N,N-Diethyl-1,3-butadienylamine with Some Diarylnitrilimines
Oido, Tatsuo,Tanimoto, Shigeo,Ikehira, Hideyuki,Okano, Masaya
, p. 1203 - 1205 (2007/10/02)
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.
