- Cp*Co(iii)-catalyzed annulation of azines by C-H/N-N bond activation for the synthesis of isoquinolines
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Herein, an efficient, atom economic and external oxidant free approach has been disclosed for the synthesis of isoquinolines. Azines were employed for annulation reactions with alkynes via sequential C-H/N-N bond activation using an air-stable cobalt catalyst. The method takes advantage of the incorporation of both the nitrogen atoms of azines into the desired isoquinoline products, offering the highest atom economy. In addition, the developed protocol works under external oxidant as well as silver salt free conditions. Furthermore, the established methodology features a relatively broad substrate scope with high product yields and scalability up to the gram level.
- Deshmukh, Dewal S.,Yadav, Prashant A.,Bhanage, Bhalchandra M.
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supporting information
p. 3489 - 3496
(2019/04/14)
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- Rapid and Atom Economic Synthesis of Isoquinolines and Isoquinolinones by C–H/N–N Activation Using a Homogeneous Recyclable Ruthenium Catalyst in PEG Media
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Herein, we report an atom-efficient, rapid, green, and sustainable approach to synthesize isoquinolines and isoquinolinones using a homogeneous recyclable ruthenium catalyst in PEG Media assisted by microwave energy. Dibenzoylhydrazine was used for C–H/N–N activation reactions for the first time in combination with ketazine as oxidizing directing groups for annulation reactions with internal alkynes. The developed protocol is environmentally benign due to significantly shortened times with an easy extraction method, higher atom economy, external oxidant and silver or antimony salt free conditions, applicability to a gram scale synthesis, use of biodegradable solvent and wide substrate scope with higher product yields. Moreover, it is worth noting that the established methodology allowed reuse of the catalytic system for up to five successive runs with minimal loss in activity.
- Deshmukh, Dewal S.,Gangwar, Neha,Bhanage, Bhalchandra M.
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supporting information
p. 2919 - 2927
(2019/05/10)
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- Rh-catalyzed sequential oxidative C-H and N-N bond activation: Conversion of azines into isoquinolines with air at room temperature
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A rhodium-catalyzed sequential oxidative C-H annulation reaction between ketazines and internal alkynes has been developed via C-H and N-N bond activation with air as an external oxidant, which led to an efficient approach toward isoquinolines with high atom efficiency at rt. Utilizing the distinctive reactivity of this catalysis, both N-atoms of the azines could be efficiently incorporated to the desired isoquinolines under very robust and mild reaction conditions.
- Han, Wenjia,Zhang, Guoying,Li, Guangxing,Huang, Hanmin
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supporting information
p. 3532 - 3535
(2014/07/21)
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- Base and solvent mediated decomposition of tosylhydrazones: Highly selective synthesis of N-alkyl substituted hydrazones, dialkylidenehydrazines, and oximes
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Base and solvent mediated decomposition of tosylhydrazones was studied. It was found that reaction of tosylhydrazones in CH3NO2 in the presence of 1 equiv of K2CO3 in 90 °C gave N-alkylated products in 52-96% yield. However, when the same reaction was carried out in mixed solvent of CH3NO2 and dioxane in the presence of 3 equiv of NaOH at 110 °C, dialkylidenehydrazines were obtained in moderate to high yield. If the reaction was carried out in mixed solvent of CH3NO2 and DMSO in the presence of 10 equiv of NaOH at 110 °C, CH3NO2 can act as the precursor of hydroxylamine and corresponding oximes were formed in up to 92% yield.
- Sha, Qiang,Wei, Yunyang
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supporting information
p. 3829 - 3835
(2013/07/05)
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- Copper-catalyzed N-N bond formation by homocoupling of ketoximes via n-o bond cleavage: Facile, mild, and efficient synthesis of azines
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A facile, mild, and efficient copper-catalyzed homocoupling of ketoximes involving N-O bond cleavage in the presence of sodium bisulfite (NaHSO has been developed. This reaction shows good functional group tolerance and affords a broad scope of azines in high yields.
- Zhao, Mi-Na,Liang, Hao,Ren, Zhi-Hui,Guan, Zheng-Hui
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experimental part
p. 1501 - 1506
(2012/06/18)
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- Synthesis of functionalized diaryl alkancs from azines
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Substituted diaryl alkanes arc synthesized from bcnzalazines and acctophenone/propiophenone azines via Friedel Craft's reaction with substituted mono- and poly-nuclear aromatic hydrocarbons. Diaryl methanes/ethanes and propanes are obtained by reaction with benzalazine, N,N'-bis (I-phenyl) azine and N, N'-bis (I-propyl) azine, respectively.
- Manih, Rudolf M.,Myrboh, Bekington
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experimental part
p. 146 - 151
(2009/12/01)
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- Formation and Reactivity of ?-Radical Cation Intermediates in the C-C Coupling Reaction of Phenyldiazomethanes by One-Electron Oxidation
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One-electron oxidation of phenyldiazomethanes afforded cis-stilbene predominantly.The reaction was independent of the oxidation methods, e.g., electrolysis, copper(II), triarylaminium salts, or photosensitized one-electron oxidtions.The C-C coupling reaction was retarded by introducing α-substituents on phenyldiazomethanes.The ESR spectra of diazoalkane radical cations could be obtained during the electrolysis at low temperature and the resulting spectra revealed their unique electronic structure as ?-radicals for most cases.When a bulky tert-butyl group was substituted, the corresponding ?-radical cation was observed, but the C-C coupling reaction did not occur.The novel HOMO-LUMO switching by one-electron removal from the HOMO ?-orbital of diazomethane is explained by the interaction of phenyl group with the C-N-N ?-radical moiety.The C-C coupling reaction proceeds via facile cycloaddition between the diazomethane and ?-radical cation, and the preferential formation of cis-olefins is based on the secondary orbital interaction between the two phenyl groups.The structure and the stability of radical cation intermediates are rationalized on the basis of ab initio calculations.
- Ishiguro, Katsuya,Ikeda, Masatoshi,Sawaki, Yasuhiko
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p. 3057 - 3066
(2007/10/02)
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- Diazomethane Radical Cations as a Dipolarophile in the Dimeric Olefin Formation from Diazo-compounds
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A novel cycloaddition mechanism involving diazomethane radical cations is proposed for the dimeric olefin formation by the one-electron oxidation of the diazo-compounds.The preference of cis-stilbene formation from phenyldiazomethane is understood by a secondary orbital interaction of phenyl groups on the cycloaddition step.
- Ishiguro, Katsuya,Sawaki, Yasuhiko,Iwamura, Hiizu
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p. 1853 - 1856
(2007/10/02)
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