- Synthesis of 1: H -indazoles by an electrochemical radical Csp2-H/N-H cyclization of arylhydrazones
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The development of efficient and sustainable C-N bond-forming reactions to N-heterocyclic frameworks has been a long-standing interest in organic synthesis. In this work, we develop an electrochemical radical Csp2-H/N-H cyclization of arylhydrazones to 1H-indazoles. The electrochemical anodic oxidation approach was adopted to synthesize a variety of 1H-indazole derivatives in moderate to good yields. HFIP was not only employed as a solvent or the proton donor, but also can promote the formation of N free radicals. This synthetic methodology is operationally simple, and less expensive electrodes would be suitable for this chemistry. This journal is
- Alhumade, Hesham,Lei, Aiwen,Li, Dongting,Wan, Hao,Xia, Huadan,Yang, Liwen,Yi, Hong
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supporting information
p. 665 - 668
(2022/01/22)
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- Synergistic effects in Fe nanoparticles doped with ppm levels of (Pd + Ni). A new catalyst for sustainable nitro group reductions
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A remarkable synergistic effect has been uncovered between ppm levels of Pd and Ni embedded within iron nanoparticles that leads to mild and selective catalytic reductions of nitro-containing aromatics and heteroaromatics in water at room temperature. NaBH4 serves as the source of inexpensive hydride. Broad substrate scope is documented, along with several other features including: low catalyst loading, low residual metal in the products, and recycling of the catalyst and reaction medium, highlight the green nature of this new technology.
- Pang, Haobo,Gallou, Fabrice,Sohn, Hyuntae,Camacho-Bunquin, Jeffrey,Delferro, Massimiliano,Lipshutz, Bruce H.
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supporting information
p. 130 - 135
(2018/01/12)
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- Divergent Synthesis of 1H-Indazoles and 1H-Pyrazoles from Hydrazones via Iodine-Mediated Intramolecular Aryl and sp3 C–H Amination
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A divergent intramolecular C–H amination of hydrazones has been developed employing molecular iodine (I2) as the sole oxidant. The required hydrazone substrates were readily obtained by condensation of hydrazines with the corresponding ketones.
- Wei, Wei,Wang, Zhen,Yang, Xikang,Yu, Wenquan,Chang, Junbiao
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p. 3378 - 3387
(2017/10/09)
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- Synthesis of indazoles and azaindazoles by intramolecular aerobic oxidative C-N coupling under transition-metal-free conditions
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A transition-metal-free oxidative C-N coupling method has been developed for the synthesis of 1H-azaindazoles and 1H-indazoles from easily accessible hydrazones. The procedure uses TEMPO, a basic additive, and dioxygen gas as the terminal oxidant. This reaction demonstrates better reactivity, functional group tolerance, and broader scope than comparable metal catalyzed reactions. A transition-metal-free oxidative C-N coupling method has been developed for the synthesis of 1H-azaindazoles and 1H-indazoles from easily accessible hydrazones (see scheme). The procedure uses TEMPO, a basic additive, and dioxygen gas as the terminal oxidant. This reaction demonstrates better reactivity, functional group tolerance, and broader scope than comparable metal catalyzed reactions. TEMPO=2,2,6,6-tetramethyl-1-piperidinyloxy.
- Hu, Jiantao,Xu, Huacheng,Nie, Pengju,Xie, Xiaobo,Nie, Zongxiu,Rao, Yu
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supporting information
p. 3932 - 3938
(2014/04/17)
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- Hydrogen Bonding in Phenylhydrazone Derivatives of Benzophenone: Crystal and Molecular Structures of Benzophenone (2-Nitrophenyl)hydrazone, containing an Intramolecular NO2...NH...? Bifurcated Hydrogen Bond, and Benzophenone (4-Nitrophenyl)hydrazone, cont
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Crystal structures have been determined of the two title compounds.The (2-nitrophenyl)hydrazone (2) is monoclinic, space group P21/a, Z = 4, with a = 12.074(5), b = 12.771(8), c = 11.998(8) Angstroem, β = 118.0 deg.The (4-nitrophenyl)hydrazone
- Drew, Michael G. B.,Willey, Gerald R.
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p. 215 - 220
(2007/10/02)
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- THE ARENEDIAZONIUM ION AS A DIPOLAROPHILE
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Azomethine ylides (methyl 3-oxido-2--acrylate, 3-methyl-2,4-diphenyloxazolium-5-olate), thiocarbonyl ylides (thiofluorenone S-methylide, thiobenzophenone S-methylide) as well as diazomethane undergo 1,3-dipolar cycloadditions to the NN-bond of 4-nitrobenzenediazonium salt.
- Bronberger, Franz,Huisgen, Rolf
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