- Mechanistic studies on the reduction of 2-bromo-1-phenylethylidenemalononitrile by NADH models BNAH and AcrH2
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Reduction of 2-bromo-1-phenylethylidenemalononitrile (BPM) by coenzyme NADH models BNPAH and AcrH2 to give 2-phenyl-1, 1-cyclopropanedicarbonitrile (PCN) and 1-phenylethylidenemalononitrile (PM), respectively, was rationalized in terms of a dir
- Liu, You-Cheng,Li, Bin,Guo, Qing-Xiang
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- Enhanced Catalytic Performance of Quasi-HKUST-1 for the Tandem Imine Formation
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Copper-based metal-organic framework (Cu3(BTC)2(H2O)3]n?nH2OMeOH (HKUST-1) has been subjected to thermolysis under air atmosphere at different temperatures ranging from 100 to 300 °C. This treatment produces the partial removal of ligands, the generation of structural defects and additional porosity in a controlled way. The resulting defective materials denoted according to the literature as quasi-MOFs, were subsequently employed as heterogeneous catalysts in the one pot synthesis of N-benzylideneaniline from aniline and benzyl alcohol in open air as terminal oxidant at 70 °C under base- and dehydrating agent-free conditions. The Q-HKUST catalysts calcined at 240 °C (QH-240) was the most efficient in the series, promoting imine synthesis. Data from Knoevenagel condensation of malononitrile shows that in QH-240 the distances of Cu ions in HKUST-1 cavities are preserved, increasing the Knoevenagel activity, but a strong rearrangement takes place at 300 °C or above. The unsaturated copper active sites with simultaneous presence of micro- and mesopores in QH-240 are responsible for this excellent catalytic performance. The effective parameters on catalytic activity of QH-240 including deligandation temperature, the amount of catalyst, the ratio of reactants, and reaction temperature as well as the stability and recyclability of the catalyst were also investigated. The possible mechanism used by QH-240 follows alcohol aerobic oxidation and subsequent anaerobic condensation of aldehyde intermediate with aniline.
- Bagheri, Minoo,Melillo, Arianna,Ferrer, Belen,Masoomi, Mohammad Yaser,Garcia, Hermenegildo
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p. 14273 - 14281
(2021/09/13)
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- One-pot oxidant-free dehydrogenation-Knoevenagel tandem reaction catalyzed by a recyclable magnetic base-metal bifunctional catalyst
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A new base-metal bifunctional catalyst NH-Pd(0)@MNP was prepared via a facile procedure and fully characterized. The as-prepared catalyst was used as an efficient relay catalyst for the one-pot oxidant-free dehydrogenation-Knoevenagel condensation tandem reaction from benzyl alcohol in H2O under mild conditions and generated benzalmalononitriles with yield up to 96%. Meanwhile, the catalyst could be easily recovered from the reaction system by an external magnetic field, and is reusable with little loss of activity up to 6 runs (5%).
- Yuan, Xiaofeng,Wan, Zijuan,Ning, Jinfeng,Zhang, Qiang,Luo, Jun
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- Reversible Multicolor Photochromism of Dihydroazulene Crystals
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The photochemical conversion of 1,8a-dihydroazulene-1,1-dicarbonitrile (DHA) to vinylheptafulvene (VHF) is a positive T-type photoswitch that is well understood in solution, but has not been explored in the solid state. Upon excitation with UV light, DHA
- Liepuoniute, Ieva,Commins, Patrick,Karothu, Durga Prasad,Schramm, Stefan,Hara, Hideyuki,Naumov, Pan?e
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p. 373 - 378
(2019/01/04)
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- Tungstate-loaded triazine-based magnetic poly(Bis-imidazolium ionic liquid): An effective bi-functional catalyst for tandem selective oxidation/Knoevenagel condensation in water
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A novel bi-functional polymeric catalyst was synthesized by immobilization of tungstate anions onto the nitrogen rich poly(ionic liquid)/magnetic nanocomposite. The resulting catalyst has two types of catalytic sites: (i) immobilized WO4 anions with bis-imidazolium ionic liquid cation for selective oxidation of alcohols and (ii) basic amine groups for Knoevenagel condensation between produced aldehyde and malononitrile. Due to the polymeric nature of the catalyst, large amounts of tungstate and basic nitrogen groups were presented on the solid surface which led to a decrease in the applied catalyst mass for catalytic reaction. High catalytic activity and excellent selectivity of catalyst in water medium make this protocol a green way for production of fine chemicals.
- Zohreh, Nasrin,Tavakolizadeh, Maryam,Hosseini, Seyed Hassan,Pourjavadi, Ali,Bennett, Craig
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p. 342 - 350
(2017/02/19)
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- Fluorous bispidine: A bifunctional reagent for copper-catalyzed oxidation and knoevenagel condensation reactions in water
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Fluorous bispidine-type ligands have been developed to facilitate its recovery and reusability and to demonstrate its bifunctional property as a ligand and base in copper-catalyzed aerobic oxidation, the Knoevenagel condensation and tandem oxidation/Knoevenagel condensation in water under mild conditions. Application of the fluorous ligand was also extended to the surfactant-free copper-catalyzed allylic and benzylic sp3 C-H oxidation reaction in water. The fluorous ligands could be recovered using F-SPE with recovery ranging from 91-97% and could be reused five times with little loss of activity.
- Ang, Wei Jie,Chng, Yong Sheng,Lam, Yulin
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p. 81415 - 81428
(2015/10/06)
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- Determination of thermodynamic affinities of various polar olefins as hydride, hydrogen atom, and electron acceptors in acetonitrile
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A series of 69 polar olefins with various typical structures (X) were synthesized and the thermodynamic affinities (defined in terms of the molar enthalpy changes or the standard redox potentials in this work) of the polar olefins obtaining hydride anions, hydrogen atoms, and electrons, the thermodynamic affinities of the radical anions of the polar olefins (X ?-) obtaining protons and hydrogen atoms, and the thermodynamic affinities of the hydrogen adducts of the polar olefins (XH?) obtaining electrons in acetonitrile were determined using titration calorimetry and electrochemical methods. The pure Ci - 'C π-bond heterolytic and homolytic dissociation energies of the polar olefins (X) in acetonitrile and the pure Ci - 'C π-bond homolytic dissociation energies of the radical anions of the polar olefins (X?-) in acetonitrile were estimated. The remote substituent effects on the six thermodynamic affinities of the polar olefins and their related reaction intermediates were examined using the Hammett linear free-energy relationships; the results show that the Hammett linear free-energy relationships all hold in the six chemical and electrochemical processes. The information disclosed in this work could not only supply a gap of the chemical thermodynamics of olefins as one class of very important organic unsaturated compounds but also strongly promote the fast development of the chemistry and applications of olefins.
- Cao, Ying,Zhang, Song-Chen,Zhang, Min,Shen, Guang-Bin,Zhu, Xiao-Qing
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p. 7154 - 7168
(2013/08/23)
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- Reaction between 2-phenyl-1,1-dicyanoallyl anion and N-methyl-2,2-dimethylpropionitrilium and N1,N2,N 2-trimethyl-2,2-dimethylpropionylamidinium trifluoromethanesulfonates
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The reaction of 2-phenyl-1,1-dicyanoallyl anion with N-methyl-2,2-dimethylpropionitrilium ion (2) in acetonitrile solution resulted in formation of [3-(N-methylamino)-4,4-dimethyl-1-phenyl-2-pentenylidene]propanedinitrile (6), which at elevated temperatur
- Kolsaker, Per,Karlsen, Hege,Romming, Christian
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p. 623 - 632
(2007/10/03)
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- Study of Mechanism of Reduction of 2-Bromo-1-(p-X-phenyl)ethylidenemalonitrile by 1-Benzyl-1,4-dihydronicotinamide and 10-Methyl-9,10-dihydroacridine
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The reduction of 2-bromo-1-(p-X-phenyl)ethylidenemalonitrile (X-BPM: X=H, F, Cl, Br, CN) by NADH models BNAH and AcrH2 has been investigated.Based on product analysis, kinetic isotope effect, and free energy relationship, a direct hydride transfer and an
- Liu, You-Cheng,Li, Bin,Guo, Qing-Xiang
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p. 9671 - 9680
(2007/10/02)
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- SYNTHESIS AND CHEMICAL REACTIVITY OF 4,4-DISUBSTITUTED PYRANAMINES
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The synthesis of a variety of 4,4-disubstituted 4H-pyranamines from alkylarylpropenenitriles and benzoylacetonitrile is reported.The reaction requirements demanded a different approach from the general synthesis of 2-amino-4H-pyrans.Electronic and steric
- Martin-Leon, Nazario,Segura, Jose L.,Seoane, Carlos,Soto, Jose L.
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p. 2434 - 2452
(2007/10/02)
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