- Origin and switch of different colors: Thermo-isomerism and crystal structure of (1E,2E)-bis[1-(4-nitrophenyl)ethylidene] hydrazine
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A new symmetric branched 4-nitrophenyl hydrazine compound has been prepared in one-step procedure by direct condensation of aromatic ketone with hydrazine in MeOH. The synthesized compound, red isomer, was characterized by IR, 1H and 13/s
- Tighadouini, Said,Radi, Smaail,Toupet, Loic,Sirajuddin, Muhammad,Hadda, Taibi Ben,Akkurt, Mehmet,Warad, Ismail,Mabkhot, Yahia N,Ali, Saqib
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Read Online
- 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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- 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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- 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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- 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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- Catalytic olefination of carbonyl compounds. Effect of the structure of the carbonyl compound on the reaction
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The mechanism of the novel reaction of catalytic olefination of carbonyl compounds was studied. The reaction involves the transformation of hydrazones of aromatic aldehydes and ketones into the corresponding dichloroalkenes and symmetrical azines by the treatment with carbon tetrachloride in the presence of CuCl as a catalyst. The stability of intermediate diazoalkanes is the main factor determining the direction of the reaction. In the case of sufficiently stable diazoalkanes, other products can be formed under the reaction conditions along with the products of catalytic olefination.
- Korotchenko,Shastin,Nenaidenko,Balenkova
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p. 492 - 497
(2007/10/03)
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- Solid-state reactivity of the hydrazine-hydroquinone complex
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The solid-state reactivities of the hydrazine-hydroquinone 1:1 complex and of hydrazine hydrochloride with solid aldehydes, ketones, carboxylic acids, thiohydantoin and 4-nitrophenyl isothiocyanate were investigated. Only the hydrazine complex provides quantitative additions, condensations, ring openings and ring closures. The solid-state mechanisms were investigated by atomic force microscopy (AFM) and the far-reaching anisotropic molecular movements are correlated with the crystal packing, both on the hydrazine complex surface and on the surface of two benzaldehydes. The hydrazine moves into the aldehyde crystals for chemical reaction without melting. Characteristic surface features are created by the common phase rebuilding and phase transformation on both the hydrazine-donating and -accepting crystals. Copyright
- Kaupp, Gerd,Schmeyers, Jens
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p. 388 - 394
(2007/10/03)
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