- Transition-Metal-Free [3 + 2] Cycloaddition of Nitroolefins and Diazoacetonitrile: A Facile Access to Multisubstituted Cyanopyrazoles
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A transition-metal-free [3 + 2] cycloaddition reaction between nitroolefins and diazoacetonitrile (N2CHCN) is described. This protocol exhibits several merits including simple starting materials, mild reaction conditions, broad substrate scope, good yields, and regioselectivities. The one-pot three-component reaction of nitroolefins with diazoacetonitrile (N2CHCN) and alkyl halides is also developed, thus delivering a series of multisubstituted cyanopyrazoles in good to high yields.
- Chen, Zhen,Zhang, Yue,Nie, Jing,Ma, Jun-An
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supporting information
p. 2120 - 2124
(2018/04/14)
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- Reactions of vinyl sulfone with α-diazo-β-ketosulfone and Bestmann-Ohira reagent for the regioselective synthesis of highly functionalized pyrazoles
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The 1,3-dipolar cycloaddition of diazomethylsulfone anion, generated in situ from α-diazo-β-ketosulfone, with vinyl sulfone proceeds in a regioselective manner to provide sulfonylpyrazoles. Similar reaction of diazomethylphosphonate anion, derived from Bestmann-Ohira reagent, with vinyl sulfone leads to phosphonylpyrazoles. The sulfonyl group of vinyl sulfone undergoes chemoselective elimination in these reactions.
- Kumar, Rahul,Nair, Deepa,Namboothiri, Irishi N.N.
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p. 1794 - 1799
(2014/03/21)
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- Synthesis of 3-cyanopyrazoles from 3-trifluoromethyl-pyrazoles via direct ammonolysis reaction
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A simple and green method to prepare 3-cyanopyrazoles in aqueous ammonia from easy-obtained 3-trifluoromethyl-pyrazoles was explored. Most substrates got acceptable yields. The hydrogen position of N1-H on cyanopyrazoles was assigned by X-ray crystal structure analysis.
- Yan, Tao,Chen, Yanhong,Wang, Jia,Xie, Yuyuan,Yang, Chunhao
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experimental part
p. 431 - 439
(2012/03/09)
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- NEW METHODS AND REAGENTS IN ORGANIC SYNTHESIS. 41. LITHIUM TRIMETHYLSILYLDIAZOMETHANE. A NEW SYNTHON FOR THE PREPARATION OF PYRAZOLES FROM α,β-UNSATURATED NITRILES
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Lithium trimethylsilyldiazomethane reacts smoothly with various α,β-unsaturated nitriles to give 3(or 5)-trimethylsilylpyrazoles in good yields.
- Aoyama, Toyohiko,Inoue, Sumie,Shioiri, Takayuki
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p. 433 - 436
(2007/10/02)
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