An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes
作者:Pankaj V. Khairnar、Tsai-Hui Lung、Yi-Jung Lin、Chi-Yi Wu、Srinivasa Rao Koppolu、Athukuri Edukondalu、Praneeth Karanam、Wenwei Lin
DOI:10.1021/acs.orglett.9b01395
日期:2019.6.7
α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further
作者:Kirill N. Zelenin、Valery V. Alekseyev、Alja R. Tygysheva、Stanislav I. Yakimovitch
DOI:10.1016/0040-4020(95)00672-u
日期:1995.10
The use of β-diketones with strong electron-withdrawing substituents in reaction with hydrazine and its monosubstituted derivatives leads to the stable intermediates of pyrazole synthesis — 5-hydroxy-4.5-dihydropyrazoles or their open chain isomers.
A mild and efficient protocol for the synthesis of fluorinated pyrazoles has been developed via gold(I)-catalyzed tandem aminofluorination of alkynes in the presence of Selectfluor. This method offers a broad substrate scope.
Scope and Limitations in the Regioselective Synthesis of 1,3,5-Trisubstituted Pyrazoles from b-Amino Enones and Hydrazine Derivatives. 13C-Chemical Shift Prediction Rules for 1,3,5-Trisubstituted Pyrazoles
作者:Alfonso González-Ortega、M. Luisa Sádaba、Angel Alberola、Luis Calvo Bleye、M. Carmen Sañudo
DOI:10.3987/com-00-9102
日期:——
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作者:K. N. Zelenin、A. R. Tugusheva、S. I. Yakimovich、V. V. Alekseev、E. V. Zerova