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
The reaction of hydroxylamine with aryl trifluoromethyl-β-diketones: Synthesis of 5-hydroxy-5-trifluoromethyl-Δ2-isoxazolines and their dehydration to 5-trifluoromethylisoxazoles
作者:Vinod Kumar、Ranjana Aggarwal、Shiv P. Singh
DOI:10.1016/j.jfluchem.2006.03.009
日期:2006.7
Reaction of hydroxylamine hydrochloride with aryl trifluoromethyl-β-diketones affords 5-hydroxy-5-trifluoromethyl-Δ2-isoxazolines rather than the reported 3-trifluoromethylisoxazoles. The structural assignment is based on the analysis of their NMR (1H, 13C and 19F) spectral data and of their dehydration products, 5-trifluoromethylisoxazoles.
The present invention is concerned with isoxazole-pyridine derivatives of formula I
wherein X, R
1
to R
6
are as described herein. The compounds are active on the GABA A α5 receptor binding site and useful for the treatment of cognitive disorders, such as Alzheimer's disease.
本发明涉及式I的异恶唑-吡啶衍生物
其中X,R1至R6如本文所述。这些化合物对GABA A α5受体结合位点具有活性,并可用于治疗认知障碍,如阿尔茨海默病。
A new and concise method for the synthesis of 5-trifluoromethylisoxazoles
作者:Xiao-Qing Tang、Chang-Ming Hu
DOI:10.1016/0022-1139(95)03252-9
日期:1995.8
A highly effective synthesis of a series of 5-trifluoromethylisoxazoles 4 from pentafluoroethyl iodide (1) and various alkynes 2 by a two-step sequence is described.
描述了通过两步顺序由五氟乙基碘(1)和各种炔烃2高效合成一系列5-三氟甲基异恶唑4的方法。
Synthesis of 5-(Fluoroalkyl)isoxazole Building Blocks by Regioselective Reactions of Functionalized Halogenoximes
作者:Bohdan A. Chalyk、Kateryna V. Hrebeniuk、Yulia V. Fil、Konstantin S. Gavrilenko、Alexander B. Rozhenko、Bohdan V. Vashchenko、Oleksandr V. Borysov、Angelina V. Biitseva、Pavlo S. Lebed、Iulia Bakanovych、Yurii S. Moroz、Oleksandr O. Grygorenko
DOI:10.1021/acs.joc.9b02264
日期:2019.12.20
halogenoximes and propargylic alcohol. An alternative approach based on nucleophilic substitution in 5-bromomethyl derivatives was found to be more convenient for the preparation of 5-fluoromethylisoxazoles. Reaction of isoxazole-5-carbaldehydes with the Ruppert-Prakash reagent was used for the preparation of (β,β,β-trifluoro-α-hydroxyethyl)isoxazoles. Utility of described approaches was shown by multigram preparation