- A novel water-dispersible and magnetically recyclable nickel nanoparticles for the one-pot reduction-Schiff base condensation of nitroarenes in pure water
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In this work, a heterogeneous nanocatalyst called Ni-Fe3O4@Pectin~PPA ~ Piconal was first synthesized, which was investigated as a bifunctional catalyst containing nickel functional groups. On the other hand, this Ni-Fe3O4@Pectin~PPA ~ Piconal catalyst in aqueous solvents shows a very effective performance at ambient temperature for the nitroarene reduction reaction with sodium borohydride, for which NaBH4 is considered as a reducing agent. This is a novelty magnetic catalyst that was approved by various methods, including Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), Dynamic light scattering (DLS), Transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Inductively coupled plasma (ICP), Energy-dispersive X-ray spectroscopy (EDX), and Field emission scanning electron microscopy (FESEM) analyses. From the satisfactory results obtained from the reduction of nitrogen, this catalytic system is used for a one-pot protocol containing a reduction-Schiff base concentration of diverse nitroarenes. It was corroborated with the heterogeneous catalytic experiments on the one-pot tandem synthesis of imines from nitroarenes and aldehydes. Finally, the novel Ni-Fe3O4@Pectin~PPA ~ Piconal catalyst could function as a more economically desirable and environmentally amicable in the catalysis field. The favorable products are acquired in good to high performance in the attendance of Ni-Fe3O4@Pectin~PPA ~ Piconal as a bifunctional catalyst. This catalyst can be recycled up to six steps without losing a sharp drop.
- Ghamari Kargar, Pouya,Ravanjamjah, Asiye,Bagherzade, Ghodsieh
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p. 1916 - 1933
(2021/07/10)
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- Influence of substituents on the structure of Schiff bases Cu(II) complexes
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The relationship between molecular conformation and substituent effects of salicylaldehyde Schiff-base Cu(II) complexes was explored. For this study, eight samples of the complexes Cu(Sal-X)2 (X = OMe, Me, H, F, Cl, Br, CF3 and CN) w
- Xiao, Yan,Cao, Chenzhong
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- Simple synthesis of the novel Cu-MOF catalysts for the selective alcohol oxidation and the oxidative cross-coupling of amines and alcohols
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A novel porous metal–organic framework {Cu2(bbda)0.5(Hbbda)1.5(OAc)1.5.8H2O} (UoB-5) was synthesized under ultrasound irradiation by employing a new Schiff base ligand H2bbda (4,4'(1,4-phenylene bis (azanylylidene)) bis (methanylylidene))dibenzoic acid) and was fully characterized. The microporous nature of UoB-5 was confirmed by gas-sorption measurements. This framework acted as a highly effective heterogeneous catalyst for the alcohol oxidation reaction with tert-butyl hydroperoxide (t-BuOOH) as an oxidant. The presence of coordinatively unsaturated metal sites in UoB-5 could be the reason for high performance in this reaction. Furthermore, using the long linker with the free -NC group and uncoordinated -N atom on the wall of the pores created UoB-5 an excellent candidate for the catalytic activities without activation of the framework. It was confirmed with the heterogeneous catalytic experiments on the one-pot tandem synthesis of imines from benzyl alcohols and anilines. Eventually, the new Cu-MOF (UoB-5) could be an alternative catalyst as a more economically favorable and environmentally friendly in the catalysis field.
- Ghamari Kargar, Pouya,Aryanejad, Sima,Bagherzade, Ghodsieh
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- Synthesis, spectroscopic characterization and computational studies of Schiff base complexes of tin(IV) chloride
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Reaction of anhydrous tin(IV) chloride with mono functional bidentate Schiff bases (sbnH), in 1:2 molar ratios, gives complexes of the type, [(sbn)2SnCl2] (1-4) (where, n=1-4; sb=2-(((4-chlorophenyl)imino)methyl
- Jaiswal, Nitesh,Kushwaha, Ajeet Kumar,Singh, Avadhesh Pratap,Dubey, Raj Kumar
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- Effect of substituents on the UV spectra of supermolecular system: Silver nanoparticles with bi-aryl Schiff bases containing hydroxyl
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Effect of substituents on the ultraviolet (UV) spectra of supermolecular system involving silver nanoparticles (AgNPs) and Schiff bases was investigated. AgNPs and 49 samples of model compounds (MC), bi-aryl Schiff bases containing hydroxyl (XBAY, involving 4-OHArCH?NArY, 2-OHArCH?NArY, XArCH?NAr-4′-OH, and XArCH?NAr-2′-OH), were synthesized. The size of AgNPs was characterized by transmission electron microscopy (TEM), and the UV absorption spectra of AgNPs, XBAYs, and MC-AgNPs mixed solutions were measured, respectively. The results show that (1) the size of AgNPs is larger in MC-AgNPs solutions than that in AgNPs solution due to the distribution of MC molecules on the surface of AgNPs; (2) the UV absorption wavelength of XBAYs changes in the action of AgNPs and their wavelength shift exists limitation between XBAY and MC-AgNPs solutions; and (3) the wavelength shift limit of MC-AgNPs (λWSL) is influenced by the substituents X and Y and the position of hydroxyl OH. The wavenumber ΔνWSL of λWSL can be quantified by employing the excited-state substituent constant σexCC and Hammett constant σ of substituents X and Y. Comparing with the 4-OH, the 4′-OH makes the ΔνWSL a red shift, whereas the 2′-OH, comparing with the 2-OH, makes the ΔνWSL a blue shift.
- Cao, Chao-Tun,Cheng, Shimao,Zhang, Jingyuan,Cao, Chenzhong
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- Copper-Catalyzed Asymmetric Annulation Reactions of Carbenes with 2-Iminyl- or 2-Acyl-Substituted Phenols: Convenient Access to Enantioenriched 2,3-Dihydrobenzofurans
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We have developed a method for the highly diastereo- and enantioselective construction of 2,3-dihydrobenzofurans bearing tetrasubstituted carbon stereocenters by means of annulation reactions between carbenes and 2-iminyl- or 2-acyl-substituted phenols through catalysis by readily accessible copper(I)/bisoxazoline catalysts under mild conditions. These reactions feature a unique mechanism in which the copper catalyst serves a dual function: first it reacts with the diazo compound to generate a metal carbene, and second, upon formation of an oxonium ylide, it acts as a Lewis acid to activate the imine or ketone for diastereo- and enantioselective cyclization.
- Liang, Xin-Shen,Li, Rui-Dong,Wang, Xiao-Chen
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supporting information
p. 13885 - 13889
(2019/08/26)
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- Substituent effects on the absorption and vibrational spectra of some 2-hydroxy Schiff bases: DFT/TDDFT, natural bond orbital and experimental study
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The electronic structure of salicylideneaniline (SA) and some of its derivatives are investigated both experimentally and theoretically. The equilibrium geometric structures of the studied compounds are determined at the B3LYP/6-311++Glevel of theory. A set of 12 substituted SA derivatives is considered in the present work. The choice of these substituents aims to create a push-pull system on the SA basic structure which would shade light onto its photo physics. The electronic absorption spectra of SA are recorded in the UV-VIS region, in both polar and nonpolar solvents. Assignments of the observed electronic transitions are facilitated via time-dependent density functional theory (TDDFT) computations at the same level of theory. Electronic configurations contributing to each excited state are identified and the relevant MOs are characterized. The extent of delocalization and intramolecular charge transfer are estimated and discussed in terms of natural bond orbitals (NBO) analysis and second order perturbation interactions between donor and acceptor MOs. Solvent effects on the electronic absorption spectra are discussed in terms of the difference in polarizabilities of the ground and excited states. FTIR spectra of SA and its derivatives are measured in KBr platelets. Detailed vibrational assignments are given based on the calculated potential energy distributions. "IR marker bands" that characterize the SA framework are identified. The effect of substituents, the nature of the characteristic "marker bands", and intensity quenching of some bands are discussed.
- Elroby,Aboud,Aziz,Hilal
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p. 414 - 427
(2015/08/06)
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- Solvent-free synthesis, spectral correlations and antimicrobial activities of some aryl imines
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A series of aryl imines have been synthesized by Fly-ash: H 2SO4 catalyzed microwave assisted process under solvent-free conditions. The yields of the imines have been found to be more than 87%. The purity of all imines has been checked using their physical constants and spectral data as published earlier in literature. The UV λmaxCN(nm), infrared νCN(cm-1), NMR δ(ppm) of CH and CN spectral data have been correlated with Hammett substituent constants and F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the above spectral data has been studied. The antimicrobial activities of All synthesised imines have been studied using Bauer-Kirby method.
- Suresh,Kamalakkannan,Ranganathan,Arulkumaran,Sundararajan,Sakthinathan,Vijayakumar,Sathiyamoorthi,Mala,Vanangamudi,Thirumurthy,Mayavel,Thirunarayanan
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p. 239 - 248
(2013/02/22)
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- A quick route for the synthesis of 3-Aryl-3,4-dihydro-2H-benz[e]-1,3- oxazin-2-ones
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N-(2-Hydroxy)-benzyl-arylamines (1) gave substantially pure 3-aryl-3,4-dihydro-2H-benz[e]-1,3-oxazin-2-one 2 on cyclization with carbonyldiimidazole in DMSO in 20-30 min at 20-25 °C in excellent yields.
- Shukla, Davender Kumar,Rani, Manju,Khan, Arif Ali
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p. 4537 - 4540
(2013/06/27)
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- Synthesis and distinct urease enzyme inhibitory activities of metal complexes of Schiff-base ligands: Kinetic and thermodynamic parameters evaluation from TG-DTA analysis
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Transition metal [Co, Ni, Cu and Zn(II) acetates] complexes of salicylaldehyde derived Schiff bases, 2-{(E)-[(4-chlorophenyl)imino]methyl} phenol (CIMP) and 2-{(E)-[(4-bromophenyl)imino]methyl}phenol (BIMP) were synthesized and characterized by various analytical and spectroscopic studies. The Schiff base ligands and their metal complexes were also screened for their urease, α-chymotrypsin, acetylcholinesterse and butyrylcholinesterase inhibition activities. The ligands were found active against α-chymotrypsin with IC50 ± S.E.M. = 305.0 ± 3.2 and 330.6 ± 1.6 μM respectively. The copper complexes of both the ligands were found active in inhibiting urease enzyme with IC50 ± S.E.M. = 10.7 ± 0.2 and 5.0 ± 0.1 μM respectively, as compared to standard inhibitor. Structure activity relationship (SAR) was evaluated using autodock programme. It was found that the active complexes block the entrance cavity to the enzyme. All the complexes were evaluated for their thermal degradation studies using TG-DTA analytical methods in static air. Thermodynamic and kinetic parameters were evaluated from the TG/DTA curves using Horowitz-Metzger method.
- Ikram, Muhammad,Rehman, Sadia,Faridoon,Baker, Robert J.,Rehman, Hanif Ur,Khan, Ajmal,Choudhary, Muhammad Iqbal,-Rehman, Saeed-Ur
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- Synthesis and biological activity of some 3-aryl-3,4-dihydro-2h-benz[e]-1, 3-oxazines/6-bromo-3-aryl-3,4-dihydro-2h-benz[e]-1,3-oxazines
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N-(2-Hydroxy)-benzyl-arylamine (1) gives substantially pure 3-aryl-3,4-dihydro-2H-benz[e]-1,3-oxazines/6-bromo-3-aryl-3,4-dihydro-2H-benz[e] -1,3-oxazines (2) on cyclization with formaldehyde in methanol within 0.5-1.0 h at 65-68 C in excellent yields. Th
- Shukla, Davender Kumar,Rani, Manju,Khan, Arif Ali,Tiwari, Kavita,Gupta, Rajinder K.
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p. 5921 - 5924
(2013/07/26)
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- An efficient route for the synthesis of 3-(4-bromophenyl)-2-phenyl-3,4- dihydro-2 H-benzo[ e ][,32,]oxazaphosphinine, its P-chalcogenides and metal complexes
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2-[(4-bromophenylamino)-methyl]-phenol (1) gave substantially pure 3-(4-bromophenyl)-2-phenyl-3,4-dihydro-2H-benzo[e][1,3,2]- oxazaphosphinine (2) on cyclization with phenyldichlorophosphine in toluene at 0 °C. Reaction of 2 with H2O2 in dichloromethane gave selectively 3. P-chalcogenides (4 and 5) were prepared by reacting 2 with elemental S and Se powder in toluene, whereas the tungsten pentacarbonyl complex 6 was prepared by reacting 2 with [W(CO)5(CH3CN)] in tetrahydrofuran at 25°C. Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures.
- Shukla, Davender Kumar,Rani, Manju,Khan, Arif Ali
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p. 1088 - 1094
(2013/09/02)
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- Exploration of α-aminophosphonate N-derivatives as novel, potent and selective inhibitors of protein tyrosine phosphatases
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Seventeen α-aminophosphonates are synthesized. Their compositions and structures are established by EA, UV, FT-IR, 1H NMR, 13C NMR, 31P NMR and ESI-MS. Compounds 1-4 are confirmed by X-ray crystallography. PTP inhibition shows compounds 1-5, 12, 15 are moderate competitive inhibitors with some selectivity. The most potent inhibitor is compound 5 with the lowest IC50 value about 6.64 μM against PTP1B, about 2-fold and 25-fold stronger than against TCPTP and PTP-MEG2 while it doesn't inhibit SHP-1 and SHP-2. The binding constant of 5 to PTP1B is 2.23 × 105 M-1 and binding ratio approximates 1:1. Cell viability and apoptosis assays indicate 5 is cell permeable with lower cytotoxicity. The results indicate α-aminophosphonates are possibly developed to effective and selective inhibitors of PTPs.
- Wang, Qingming,Zhu, Miaoli,Zhu, Ruiting,Lu, Liping,Yuan, Caixia,Xing, Shu,Fu, Xueqi,Mei, Yuhua,Hang, Qingwei
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experimental part
p. 354 - 364
(2012/04/23)
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- The substituent effects on the 13C chemical shifts of the azomethine carbon atom of N-(substituted phenyl)salicylaldimines
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Hammett correlations between the 13C-NMR chemical shifts of the azomethine carbon atom and the corresponding substituent constants were established for thirteen Schiff bases. The successful correlation of the chemical shifts with the electrophilic substituent constants σ+ indicate a significant resonance interaction of the substituents on the aniline ring with the azomethine carbon atom in the examined series of imines. The demand for electrons in the investigated compounds was compared to that of the N-benzylideneanilines and N-(substituted phenyl)pyridinealdimines. The manner of transmission of the substituent effects is discussed and they were separated into resonance and inductive effects. The inductive effects prevail over the resonance effects.
- Drmanic, Sasa Z.,Marinkovic, Aleksandar D.,Nikolic, Jasmina B.,Jovanovic, Bratislav Z.
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p. 993 - 1001
(2012/10/29)
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- GREEN SYNTHESIS OF ARYL ALDIMINES USING ETHYL LACTATE
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The present invention relates to a method for preparing aryl aldimines. In particular, the present invention relates to methods of preparing aryl aldimines that uses environmentally friendly solvent systems.
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-
Page/Page column 4-5
(2011/08/22)
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- Catalytic asymmetric mannich-ketalization reaction: Highly enantioselective synthesis of aminobenzopyrans
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"Chemical Equation Present" Domino catalysis: We have developed the first enantioselective domino Mannich-ketalization reaction of o-hydroxy benzaldimines with electron-rich alkenes (see scheme). The new reaction sequence provides an easy and direct acces
- Rueping, Magnus,Lin, Ming-Yuan
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supporting information; experimental part
p. 4169 - 4172
(2010/07/05)
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- Catalytic asymmetric inverse-electron-demand (IED) [4+2] cycloaddition of salicylaldimines: Preparation of optically active 4-aminobenzopyran derivatives
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The catalytic asymmetric inverse-electron-demand (IED) [4+2] cycloaddition of various salicylaldehyde-derived N-arylimines with electron-rich alkenes in the presence of chiral BINOL-derived phosphoric acid catalysts has been studied with the aim of obtaining optically active 4-aminobenzopyran derivatives. Dienophiles such as 2,3-dihydro-2H-furan, benzyl N-vinylcarbamate and 2-vinylindole have been employed. Copyright
- Bernardi, Luca,Comes-Franchini, Mauro,Fochi, Mariafrancesca,Leo, Virginia,Mazzanti, Andrea,Ricci, Alfredo
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supporting information; experimental part
p. 3399 - 3406
(2011/02/23)
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- Synthesis, crystal structure and electronic properties of bis(N-2-bromophenyl-salicydenaminato)copper(II) complex
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A new series of complexes of the type bis(N-substituted-salicydenaminato)copper(II) (1-9), have been synthesized and characterized by IR, UV-Vis and elemental analysis methods. The molecular structure of bis(N-2-bromophenyl-salicydenaminato)copper(II) (6)
- Vafazadeh, Rasoul,Hayeri, Vahid,Willis, Anthony C.
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experimental part
p. 1810 - 1814
(2010/07/04)
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- Synthesis and antifungal activity of some new 1, 2-benzisoxazole
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Various 3H-N-substituted phenyl / thiazolyl 1,2-benzisoxazole have been synthesized by the reaction of schiffs base with DMSO-I2 in presence of H2SO4 and characterized by IR,NMR spectral studies and elemental analysis. These compounds showed significant activities against plant pathogenic fungi viz. Alterneria burnsii and Macrophomina phasiolina.
- Sareen,Khatri,Shinde,Chugh,Sareen
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experimental part
p. 33 - 34
(2011/06/21)
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- Ethyl lactate as a tunable solvent for the synthesis of aryl aldimines
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Ethyl L-lactate can be tuned with a cosolvent to create polarity conditions ideal for synthesizing aryl aldimines that crystallize directly out of solution within minutes under ambient conditions in excellent yields and requiring no further purification.
- Bennett, Jacqueline S.,Charles, Kaitlyn L.,Miner, Matthew R.,Heuberger, Caitlin F.,Spina, Elijah J.,Bartels, Michael F.,Foreman, Taylor
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body text
p. 166 - 168
(2010/04/22)
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- Indium-mediated deoxygenation of nitrones, N-oxides and deoxygenative reductive coupling of nitrones to vicinal diamines
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We reported transformation of nitrones selectively either to aldamines or vicinal diamines and deoxygenation of N-oxides using Indium at ambient temperature in good yields.
- Jeevanandam, Arumugasamy,Cartwright, Charles,Ling, Yong-Chien
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p. 3153 - 3160
(2007/10/03)
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- Photochromic materials for reversible switching of second order nonlinear optical properties
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This paper reports on materials whose second order nonlinear optical (NLO) properties can be switched by light. We synthesized and studied the properties of a series of substituted N-salicylidene anilines which are noncentrosymmetric and photochromic crys
- Poineau, Frederic,Nakatani, Keitaro,Delaire, Jacques A.
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- Synthesis, IR Spectra, and Structure of Chelate Compounds of Oxotungsten(VI) with o-Hydroxyazomethines; Crystal Structures of the Oxotrichloro(salicylal-4-R-phenyliminato)tungsten(VI) Complexes (R=Me, Br, and OMe)
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Syntheses and IR spectroscopic investigations of seven compounds of the[WOCl3(L)] type with different R substituents in position 4 of the ligand L [R=Me (I), Br (II), OMe (III), OH (IV), H (V), COOEt (VI), and NO2 (VII)] and of the [WOCl(OMe)2(L)] complex, where R=Br (VIII) are carriedout. The suggestion that compounds I-VII have a mer-octahedral structure made on the bases of IR spectroscopy is supported by the results of anX-ray diffraction study of complexes I-III.
- Sergienko, V. S.,Abramenko, V. L.,Ilyukhin, A. B.,Kovalenko, Yu. V.
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p. 1095 - 1102
(2008/10/08)
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- Synthesis and Characterisation of Binuclear Silicon-Aluminium and Arsenic-Aluminium Complexes with Schiff Bases
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Trimethylsilyl acetate or phenylarsonic acid on reaction with aluminium isopropoxide yields two new series of complexes of the types, (CH3)3Si-O-Al(OPri)2 and .The isopropoxy groups in these derivatives further undergo facile reactions with bidentate Schiff bases giving coloured complexes of the types (CH3)3Si-O-Al(SB-H)2 and respectively, where SB-H is deprotonated form of the Schiff base.The Si-Al type of compounds are monomeric in nature and nonelectrolytes in DMF and DMSO, where the As-Al type of derivatives are insoluble in most of the organic solvents and appear to be polymeric in nature.A few compounds have been found to be quite effective as potential pesticides.
- Chaturvedi, Vibhav,Tandon, J. P.
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p. 422 - 424
(2007/10/02)
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- REACTIONS OF DICHLOROBIS(CYCLOPENTADIENYL)ZIRCONIUM(IV) WITH BIDENTATE SCHIFF BASES DERIVED FROM SALICYLALDEHYDE AND 4-SUBSTITUTED ANILINES
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Dichloro bis(cyclopentadienyl)zirconium(IV), Cp2ZrCl2, reacts with bidentate Schiff bases such as salicylidene-4-anisidine, salicylidene-4-phenetidine, salicylidene-4-chloroaniline, salicylidene-4-bromoaniline, salicylidene-4-iodoaniline and salicylidene-4-nitroaniline in a 1:1 molar ratio in refluxing tetrahydrofuran in the presence of triethylamine to yield Cp2Zr(SB)Cl, where (SB)- is the anion of the corresponding Schiff base, SBH.The new derivatives have been characterized on the basis of elemental analysis, molecular weight determination, conductance measurement and spectral (IR, 1H NMR) and electronic studies.
- Sharma, A. K.,Khera, B.,Kaushik, N. K.
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p. 123 - 130
(2007/10/02)
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- (Chloro)(N-arylsalicylaldiminato)bis(indenyl)titanium(IV) Compounds
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Titanium(IV) complexes of the type (C9H7)2Ti(SB)Cl have been synthesised by the reaction of bis(indenyl)titanium(IV) dichloride and bidentate schiff base (SBH) in a 1:1 molar ratio in refluxing tetrahydrofuran in the presence of triethylamine.The new complexes have been characterised on the basis of their elemental analyses, conductance measurements and spectral (IR, 1H NMR and electronic) studies.
- Sharma, Anand,Khera, Brij,Kaushik, Narender K.
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p. 816 - 817
(2007/10/02)
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- Bis(indenyl)zirkonium(IV) Complexes of Monofunctional Bidentate Salicylidimines
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A series of (C9H7)2Zr(SB)Cl complexes where SB(-) is the anion of bidentate Schiff base derived from salicylaldehyde and 4-substituted anilines, viz. salicylidene-4-anisidine, salicylidene-4-phenetidine, salicylidene-4-chloroaniline, salicylidene-4-bromoaniline, salicylidine-4-iodoaniline and salicylidine-4-nitroaniline, have been synthesized by the reaction of bis(indenyl)zirconium(IV)dichloride and Schiff base (SBH) in 1:1 molar ratio in refluxing THF in the presence of triethylamine.The new derivatives have been characterized on the basis of their elemental analyses, conductance measurements and spectral (IR, 1H-NMR, UV-VIS) studies. - keywords: Bis(indenyl)zirconium(IV) complexes; Schiff base; Conductance; IR; 1H-NMR; UV-VIS
- Sharma, A. K.,Khera, B.,Kaushik, N. K.
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p. 907 - 914
(2007/10/02)
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