- 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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- Cs2CO3-mediated decomposition of N-tosylhydrazones for the synthesis of azines under mild conditions
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Abstract: A facile, environmentally and efficient Cs2CO3-mediated decomposition of N-tosylhydrazones reaction has been developed for the synthesis of functionalized azines under mild conditions. This method offers broad substrate scope, occurs as additive-free, without strong base conditions, utilizes readily available reactants, and forms products in good to high yields. Graphical Abstract: [Figure not available: see fulltext.]
- Luo, Zai-Gang,Liu, Peng,Fang, Yu-Yu,Xu, Xue-Mei,Feng, Cheng-Tao,Li, Zhong,Zhang, Xiao-Mei,He, Jie
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p. 1139 - 1148
(2017/02/10)
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- Monohydrocyanation of symmetrical azines using potassium hexacyanoferrate(II) as an environmentally friendly cyanide source
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The monohydrocyanation of symmetrical azines to synthesize α-hydrazinonitriles using potassium hexacyanoferrate(II) as cyanide source and benzoyl chloride as a promoter under catalyst-free conditions is described. The advantages of this protocol are the environmentally friendly cyanide source, high yield, and simple work-up procedure. Georg Thieme Verlag Stuttgart New York.
- Hu, Xiaochun,Li, Hongbo,Yang, Jingya,Li, Zheng
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supporting information
p. 1786 - 1790
(2014/08/05)
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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 sulfones by iron-catalyzed decomposition of sulfonylhydrazones
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The Fe-catalyzed decomposition of sulfonylhydrazones gives rise to sulfones. The reaction is quite general and allows the preparation of sulfones from a variety of aryl, alkyl, and α,β-unsaturated aldehydes and ketones. Crossover experiments reveal that the reaction is an intermolecular process, which may proceed by nucleophilic attack of the sulfinate anion on an iron carbene complex. Carbonyl compounds can be easily transformed into sulfones by Fe-catalyzed decomposition of the corresponding sulfonylhydrazones. The process most likely proceeds through an iron carbene complex and opens the door for the design of othernovel Fe-catalyzed reductive couplings. Copyright
- Barluenga, Jose,Tomas-Gamasa, Maria,Aznar, Fernando,Valdes, Carlos
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scheme or table
p. 1520 - 1526
(2011/04/25)
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- The electrochemical reduction of 1,4-dichloroazoethanes: Reductive elimination of chloride to form aryl azines
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A series of 1,4-dichloroazoethanes (1-X/Y, X and Y = 4-NO2, 4-CN, 4-CH3 or 4-H) were studied in N,N-dimethylformamide using cyclic voltammetry, constant potential sweep voltammetry (CPSW) and constant potential electrolysis. The voltammograms of 1-X/Y exhibit an irreversible two-electron wave corresponding to dissociative electron transfer (DET) reduction of the carbon-chlorine bond resulting in formation of the azines 2-X/Y in quantitative yield. Additional redox waves correspond to the reversible reduction of the azines to the 2-X/Y?- radical anion and 2-X/Y2-dianion consecutively, with the exception of 1-NO 2/NO2 where both NO2 groups are reduced simultaneously in a two-electron reversible wave. Thermodynamic and kinetic parameters were determined from CPSW: the standard reduction potentials (E o) vary between-0.7 and-1.3V versus SCE as a function of electron-withdrawing substituent; the heterogeneous rate constants (khet) are consistent with a slow heterogeneous electron transfer with values ranging from 10-3 to 10-5 cms-1; the transfer coefficients (α) for 1-NO2/NO2 and 1-NO2/H are greater than 0.5, indicative of a stepwise DET mechanism for the C-Cl bond cleavage while the remaining 1-X/Y compounds have α values between 0.35 and 0.5, and the intrinsic barriers are all significantly lower than predicted for a concerted DET, thereby also suggesting a stepwise DET mechanism.
- Sauro, Vittorio A.,Magri, David C.,Pitters, Jason L.,Workentin, Mark S.
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scheme or table
p. 5584 - 5591
(2010/09/06)
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- RHODIUM ION CATALYZED DECOMPOSITION OF ARYLDIAZOALKANES
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Aryldiazomethanes are converted by rhodium(II)acetate and iodorhodium(III) tetraphenylporphyrin to cis- rather than trans-1,2-diarylethylenes.Secondary aryldiazoalkanes react with rhodium(II) acetate to give azines.
- Shankar, B.K. Ravi,Shechter, Harold
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p. 2277 - 2280
(2007/10/02)
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- Reaction of t-Butyl β-Methyl-β-arylglycidic Esters with Hydrazine
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A series of t-butyl β-methyl-β-arylglycidic esters have been prepared by the Darzens condensation.In contrast to ethyl β-phenylglycidic esters which have been reported to yield the products corresponding to hydroxy 4-pyrozolidin-3-one, treatment of t-butyl β-methyl-β-phenylglycidic esters with hydrazine hydrate yields the products corresponding to the acetophenone azines.The products have been characterized on the basis of their elemental analyses and IR, PMR and mass spectral data.
- Sethi, Kanta,Kirmani, M. Z.
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p. 421 - 422
(2007/10/02)
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