- Isolation and structural characterization of the elusive 1:1 adduct of hydrazine and carbon dioxide
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A solid hydrazine was isolated as a crystalline powder by reacting aqueous hydrazine with supercritical CO2. Its structure determined by single crystal X-ray diffraction shows a zwitterionic form of NH3 +NHCO2-. The solid hydrazine is remarkably stable but is as reactive as liquid hydrazine even in the absence of solvents.
- Lee, Byeongno,Kang, Seung Hee,Kang, Donghyeon,Lee, Kyu Hyung,Cho, Jaeheung,Nam, Wonwoo,Han, Oc Hee,Hur, Nam Hwi
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- Salieylaldehyde azines as fluorophores of aggregation-induced emission enhancement characteristics
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A series of salicylaldehyde azine derivatives were found to exhibit interesting aggregation-induced emission enhancement (AIEE) characteristics. In good solvent, all these compounds displayed very weak fluorescence, while strong emission was observed when they were placed in poor solvent. Moreover, the AIEE color of these compounds varied from green to red depending on the substituents on azines. Their in situ formation also promises potential applications in fluorescence sensing of hydrazine.
- Tang, Weixin,Xiang, Yu,Tong, Aijun
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- Ruthenium(ii)-catalysed 1,2-selective hydroboration of aldazines
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Herein, an efficient and simple catalytic method for the selective and partial reduction of aldazines using ruthenium catalyst [Ru(p-cymene)Cl2]2 (1) has been accomplished. Under mild conditions, aldazines undergo the addition of pinacolborane in the presence of a ruthenium catalyst, which delivered N-boryl-N-benzyl hydrazone products. Notably, the reaction is highly selective, and results in exclusive mono-hydroboration and desymmetrization of symmetrical aldazines. Mechanistic studies indicate the involvement of in situ formed intermediate [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] (1a) in this selective hydroboration.
- Gunanathan, Chidambaram,Pradhan, Subham,Thiyagarajan, Subramanian
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supporting information
p. 7147 - 7151
(2021/08/30)
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- Non-Pincer-Type Arene Ru(II) Catalysts for the Direct Synthesis of Azines from Alcohols and Hydrazine under Aerobic Conditions
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We report a tandem approach to synthesize symmetrical azines from alcohols and hydrazine hydrate catalyzed by synthesized arene Ru(II) complexes of aroylthiourea ligand. Notably, the catalytic efficiencies of six- and four-membered N,S-chelate ruthenium c
- Saranya, Sundar,Ramesh, Rengan,Sémeril, David
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p. 3194 - 3201
(2020/09/15)
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- Glucose:urea:NH4Cl low melting mixture for the synthesis of symmetric azines
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Alternate reaction media have become very important due to the problems created by the highly volatile nature of the solvents. The deep eutectic mixture is a kind of an alternate reaction medium which has emerged in recent years. Low melting mixtures were introduced by making the deep eutectic mixture more cost-effective and renewable by introducing carbohydrates into it. The properties of low melting mixtures include easiness to prepare, usage of low-cost components, biodegradability, solubility in water, easy separation from organic compounds, etc. The low melting mixtures such as glucose:urea:NH4Cl, glucose:ChCl, glucose:urea:ChCl, glycerol:urea:NH4Cl, and ethylene glycol:urea:NH4Cl were used in different ratios for the reactions. The properties such as viscosity, density, acidity, glass transition temperature, and thermal stability were studied. An unusual method for the synthesis of symmetrical azines is introduced wherein benzaldehyde and hydroxylamine are reacted in the presence of glucose:urea:NH4Cl. The method of synthesis needs only less reaction time, temperature and the product was easily separated. The products were confirmed using GC-MS and NMR techniques. The recyclability of glucose:urea:NH4Cl was studied.
- Theresa, Letcy V.,Shaibuna,Sreekumar
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p. 3148 - 3160
(2019/09/03)
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- Ligand Redox-Controlled Tandem Synthesis of Azines from Aromatic Alcohols and Hydrazine in Air: One-Pot Synthesis of Phthalazine
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A controlled tandem synthetic route to azines from various alcohols and hydrazine hydrate by the use of a Ni(II) complex of 2,6-bis(phenylazo)pyridine as a catalyst is reported. In marked contrast to the previous report, the reaction is operative using an earth-abundant metal catalyst, milder reaction conditions, and aerobic conditions, which though are desirable but unprecedented in the literature. The catalytic reaction has a vast substrate scope including a single-step synthesis of phthalazine from 1,2-benzenedimethanol and hydrazine hydrate via intramolecular coupling. Mechanistic investigation suggests that the coordinated ligand redox controls the reaction by the use of a reversible azo (N=N)/ hydrazo (NH - NH) redox couple where the metal center is used primarily as a template.
- Chakraborty, Mou,Sengupta, Debabrata,Saha, Tanushri,Goswami, Sreebrata
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supporting information
p. 7771 - 7778
(2018/06/11)
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- Unusual synthesis of azines and their oxidative degradation to carboxylic acid using iodobenzene diacetate
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Reaction of 3-hydrazonobutan-2-one oxime with aromatic aldehydes resulted in the formation of 1,2-bis(arylidene)hydrazine commonly referred as azine as an unexpected product, instead of expected product 3-(aryl)methylenehydrazonobutan-2-one oxime, which were subsequently oxidized to corresponding aromatic acids with an ecofriendly oxidizing agent iodobenzene diacetate. Azines and carboxylic acids were characterized by IR and NMR (1H, 13C, HMBC, and HMQC) studies.
- Sumran, Garima,Aggarwal, Ranjana,Hooda, Mona,Sanz, Dionisia,Claramunt, Rosa M.
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supporting information
p. 439 - 446
(2018/02/06)
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- Aldazines in the Castagnoli-Cushman Reaction
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Aldazines were employed in the Castagnoli-Cushman reaction of homophthalic anhydride for the first time. The reaction proved to be distinctly diastereoselective when conducted at room temperature in acetonitrile, yielding predominantly the kinetic cis -co
- Mikheyev, Alexander,Kantin, Grigory,Krasavin, Mikhail
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p. 2076 - 2086
(2018/03/29)
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- A Copper-Benzotriazole-Based Coordination Polymer Catalyzes the Efficient One-Pot Synthesis of (N′-Substituted)-hydrazo-4-aryl-1,4-dihydropyridines from Azines
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A series of new (N′-substituted)-hydrazo-4-aryl-1,4-dihydropyridines was successfully synthesized via a facile one-pot catalytic pathway utilizing azines and propiolate esters as starting materials and a one-dimensional copper benzotriazole-based coordination polymer as catalyst. In the absence of catalyst, the corresponding 5-substituted 4,5-dihydropyrazoles were formed in moderate to high yields. Fine-tuning of the catalysts allowed us to gain more insights regarding the plausible reaction mechanism. (Figure presented.).
- Kallitsakis, Michael,Loukopoulos, Edward,Abdul-Sada, Alaa,Tizzard, Graham J.,Coles, Simon J.,Kostakis, George E.,Lykakis, Ioannis N.
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supporting information
p. 138 - 145
(2017/01/14)
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- Selective Reduction of Azines to Benzyl Hydrazones with Sodium Borohydride Catalyzed by Mesoporous Silica-Supported Silver Nanoparticles: A Catalytic Route towards Pyrazole Synthesis
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The catalytic activity of supported silver nanoparticles on mesoporous silica was studied, for the selective reduction of azines into benzyl hydrazones using sodium borohydride as mild reducing agent. Different sizes of silver nanoparticles supported on mesoporous silica (Ag/HMS) were successfully prepared by two methods, i.e., wet impregnation followed by reduction with hydrogen at 350 °C and in situ deposition/reduction with a mixture of amines (ethanolamine and ethylenediamine). The Ag/HMS (amines) catalyst was found to promote the selective 1,2-reduction of aryl-substituted azines, compared to the corresponding 1,4-reduction that occurs in general reduction processes. This catalytic transfer hydrogenation process found to be clean, fast and quantitative (>99% yields and selectivity) towards benzyl hydrazone synthesis under mild conditions. Of great importance is that under the present catalytic conditions reducible functional groups remain intact. Formal kinetics, support the in situ formation of silver hydride species being responsible for the reduction process. The presence of protic polar methanol enhanced the catalytic activity of Ag/HMS. Based on the recycling studies the catalytic system Ag/HMS-NaBH4 was found to catalyze the selective reduction of azines nine times without significant loss of its activity. Finally, a one-pot reaction between the in situ produced benzyl hydrazones and a series of nitrostyrenes readily provided the regioselective synthesis of 1,3,5-subtituted pyrazoles, highlighting a useful synthetic application of the catalytic protocol. (Figure presented.).
- Charistoudi, Evangelia,Kallitsakis, Michael G.,Charisteidis, Ioannis,Triantafyllidis, Kostas S.,Lykakis, Ioannis N.
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supporting information
p. 2949 - 2960
(2017/09/08)
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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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- An expeditious synthetic approach towards the synthesis of Bis-Schiff bases (aldazines) using ultrasound
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Aldazines (Bis-Schiff bases) 1-24 were synthesized using aromatic aldehydes (heterocyclic and benzaldehydes) and hydrazine hydrate under reflux using conventional heating and/or via ultrasound irradiation using BiCl3 as catalyst. Ultrasonication conditions with cat. BiCl3 proved to be an effective, environmentally friendly synthetic procedure. This methodology is robust in the presence of electron donating and electron withdrawing groups affording desired products with high yields (>95%) in just a couple of minutes vs. hours using conventional heating.
- Khan, Khalid M.,Jamil, Waqas,Ambreen, Nida,Taha, Muhammad,Perveen, Shahnaz,Morales, Guillermo A.
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p. 1200 - 1205
(2014/02/14)
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- A novel approach to 2-chloro-2-fluorostyrenes
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A new general catalytic olefination reaction (COR) of aromatic and heteroaromatic aldehydes and ketones was applied to synthesise 2-chloro-2-fluorostyrenes. The two-stage procedure includes the transformation of carbonyl compounds into hydrazones followed by treatment with CFCl3 mediated by copper catalysis. Trichlorofluoromethane was used as a chlorofluoromethylene transfer reagent. The reaction proceeds stereoselectively and the target alkenes were obtained in high yield. A proposed mechanism for the reaction is discussed. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Nenajdenko, Valentine G.,Shastin, Alexey V.,Korotchenko, Vasily N.,Varseev, Georgy N.,Balenkova, Elisabeth S.
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p. 302 - 308
(2007/10/03)
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- One-pot oxidation of azomethine compounds into arenecarboxylic acids
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Aromatic azomethine compounds, such as aldazines 1, aldoximes 7 and tosylhydrazones 8 oxidized with 30% hydrogen peroxide in the presence of poly(bis-1,2-phenylene) diselenide (6) as catalyst produce arenecarboxylic acids 2 mostly in high to excellent yields. The presented one-pot procedure has a synthetic value.
- Giurg,Said,Syper,Mlochowski
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p. 3151 - 3159
(2007/10/03)
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- A novel approach to fluoro-containing alkenes
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A new and general one-pot transformation of aromatic aldehydes to fluorinated olefins containing -CH=C(Cl)CF3 or -CH=C(F)CClF2 moieties is described. Freons CCl3CF3 and CCl2FCClF2 were used as trifluoromethyl and difluoromethyl C2-building blocks respectively. A proposed mechanism for the reaction is discussed.
- Korotchenko, Vasily N,Shastin, Alexey V,Nenajdenko, Valentine G,Balenkova, Elisabeth S
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p. 7519 - 7527
(2007/10/03)
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- CHLOROSULFONATION OF DIARYL AZINES
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Benzaldehyde- and o-, m-, p-anisaldehyde azines; thiophene-2-carboxaldehyde, and biphenyl-4-carboxaldehyde azines (1-8) reacted with excess chlorosulfonic acid to give the disulphonyl chlorides (1a-8a).These were condensed with amines and hydrazine to give 27 derivatives, (Table I) for biocidal evaluation.The orientation of sulfonation is discussed in relation to the stereoelectronic factors and the spectral data.Attempted chlorosulfonation of furan-2-carboxaldehyde azine (9) gave an impure product which could not be clearly characterized as the morpholidate derivative.
- Cremlyn, Richard J.,Swinbourne, Frederick J.,Graham, Stephen,Cavaleiro, Jose A. S.,Domingues, Fernando J.,Dias, Maribel
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- Charge-tansfer complexes of substituted aromatic azines and ?-acceptors
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Charge-transfer complexes of symmetrically substituted aromatic azines with tetracyanoethylene (TCNE) and 1,4-benzoquinones in methylene chloride have been investigated spectrophotometrically.The spectral data, molar extinction coefficients and transition energies of the complexes formed as well as the ionization potentials of the electron donors are reported.Both BENSI-HILDEBRAND and JOB methods have been applied in determination of association and apparent formation constants respectively.Substituent effect on charge-transfer equilibria of the substituted azines has been discussed.
- Mourad, Aboul-Fetouh E.
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p. 933 - 938
(2007/10/02)
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